saw plates old VS new

[Zahid Naqvi]

I am very frugal when it comes to woodworking tools, purely functional when it comes to tool choices with no regard for brand names. That is why almost all of my tools are rehabbed old tools and some tuned up new tools. Hand saws are one thing I have not played around with much, other than learning how to hand sharpen them. I have one of those new Stanley back saws that comes with a very high end black plastic handle ;). The theory was the plate has got to be good enough and if I can put a nice wooden handle on it, it should serve my needs. Well I have had it for a few years now and it's been through a few sharpenings too. In general I have no issues. It's definitely "not" at the level of LV/LN or Wenzlof, but probably about 75% there. I had the opportunity to test a LV tenon saw courtesy of a local WWers and I could see that the saw was of top quality. Still the "jigged up" Stanley is good enough for me.

That brings me to my question. With my propensity to be frugal is it a better choice to hunt down old saws and look for something with a good plate or go buy a new one from the local borg. I probably will replace the handle in both cases (for some reason I prefer a thicker grip than stock even though I do not have big hands). Is there anything special in the older saw plates which it missing from the newer ones?

[Jonathan McCullough]

The older- and older-style saws have nice thick, heavy backs, so they seem to track with a bit more momentum and authority. The borg saws' backs are just enough to keep the thin sawplate straight, but they're so flimsy you can bend them with your hands. Some of the borg saws also have teeth that are kind of serrated and set about every 1/2 inch in a curious wave instead of properly filed and individually set teeth. Anyone's guess about the steel. Could be okay but I think there's probably a good chance of a lot of chrome, tungsten, vanadium to toughen them up for a life of abuse from Joe Nosepick ("this hack saw is for metal right? And deer bones?"). No idea on how much carbon or whether it's properly tempered--they're never blue so you can't tell, and I haven't been able to find a mass spectrometer or hardness tester at a garage sale yet. If they sharpen well and do what you ask I suppose it doesn't matter, but it's kind of nice to start out knowing you've got what's generally accepted as being the best tool that's constructed with what are known to be the best materials. As for the handles, I wouldn't mind plastic with foam grippy stuff as long as it were ergonomic. But we're wood workers, and well proportioned classic saw handles made from the right woods are striking, useful, comfortable, and something we can do ourselves--or at least admire if our interests are solely the use of such saws.

[Nixon Roger]

Another "frugal" guy here. I have a couple of Wenzloffs and several Disston #4's. If you like old tools and fixing them, you will love old saws. My Disstons aren't as pretty as my Wenzloffs and I can't sharpen like Mike & his boys but I enjoy them a lot.

[Johnny Kleso]

All of my users (main users) I have 20-30 back saws :) are Tyzack and Turner back saws I bought at eBay for less than $60 each of the 8", 10", 12" and 14" that where sold at WoodCraft during the 70s Thhe company is about or was about 100 years old and high quality..

As for CC and rip saws buy a nice Sears ovver a old beat up bent and rusty Diston..
Find the nice old saws on eBay that are not as colllectable you can find some really nice saws for not to much if you put in the time..

[Nixon Roger]

I found this rusty Disston at a flea market for $2.

http://lh3.ggpht.com/_QRUXtO_KnZ0/Szug0CuPZVI/AAAAAAAAAnQ/W-VP2-n_n1I/s800/IMG_0025.JPG

After about an hour it looked like this:

http://lh4.ggpht.com/_QRUXtO_KnZ0/Szug1W-f7OI/AAAAAAAAAnY/Yj6gzidkrjc/s800/IMG_0027.JPG

Nice Disston #12 with nib. What does Sears have that is comparable?

[Johnny Kleso]

Sears at one time sold Atkins saws oof a high quality...
I cant find any right now at eBay but the point is I would not spend my time on an old pitted saw just because it WAS a quality saw at one time..

IMHO I would buy a Sandvik saw like this that sold at eBay for $12.50
Sandvik makes the highest quality spring steel (saw steel)
190270190272190271

[Johnny Kleso]

Zahid,
Here is a pic of the 1950's Diston saws I started out with
190276

Then you can not see so well the four Tyzack back saws at bottom..
I have bought about 100 saws over the last 10 years and have scraped, cleaned, filed and set then as well as refinsh handles..
When it comes to saws you want a bright shiny smooth and slick surface..
There is almost no difference in quality of steel and just a little in taper ground blades..
I worked at my last job mantaining the machines of a saw blade maker..
If you looking for saws to cut wood and not collect a Sandvik or older Sears saw in very good conndition is the way to go..

190277

[Jim Koepke]

That brings me to my question. With my propensity to be frugal is it a better choice to hunt down old saws and look for something with a good plate or go buy a new one from the local borg.

The last borg saw I bought was for my son almost 20 years ago.

It is not that great of a saw, but allowed my son to cut up pieces of wood. I still have the saw and it is at the bottom of the pile.

I have a few Disston back saws. Some were my dad's that he bought in the 50s or 60s. They work OK, but they do not seem to hold an edge as well as the older saws that I have picked up at antique stores and yard sales. My current favorite is a Disston that I think is about 16" and filed for cross cut. It cost me $6 in an antique shop.

Today I had to cut off some legs from a table in the greenhouse that had been attacked by carpenter ants. (If only they were union and I could get them to do carpentry to my design.) I used one of my beaters, an old Simonds "Warranted Superior" with about 5 ppi. Even without any thing to hold the double 2X4 legs still but my other hand the cuts all came out almost as square as if they were done on a bench with a hook. These were kind of wiggly and up in the air about 4'. I was impressed by how well that old saw does its work.


Some of the borg saws also have teeth that are kind of serrated and set about every 1/2 inch in a curious wave instead of properly filed and individually set teeth.

That is one of the new ideas in commercial saws. Instead of variable pitch or rake, they are going with variable set. :rolleyes:

jtk

[David Weaver]

The FTJ tool sale was up this morning with some nice saws. I got a nice groves rip saw for $35.

I would say old saws are nicer. they won't crosscut as fast as a new saw with japanese teeth, but they sure do feel a lot better, and they are easy to refresh (and can be made to do a finer finish).

Unless you are really lucky, though, if you buy all old saws, you will end up with ones that you aren't too excited about.

But I would still buy old saws. they have a ring, tension and taper that new saws don't have. (we are talking about frugal buyer's saws).

I would find decent D8s or #7s, whatever your flavor is (whichever handle style you like), and plan to spend $10 at a flea market or $40 or a little more online if you're going to get from a seller who is honest.

What do you need? Panel or carpenters saws, rip or crosscut? Or do you need a whole kit of stuff that will do everything short of resawing wide boards?

[john brenton]

That's some serious big tooth/little tooth going on right there. Looks like the kind of sharpening job I would do. I was kicking myself for not picking up a pair of old new stock, top of the line Sandvik saws. I saw them online for cheap but decided not to because of the handle...but then I saw one in person and the handle was very comfortable.



IMHO I would buy a Sandvik saw like this that sold at eBay for $12.50
Sandvik makes the highest quality spring steel (saw steel)
190270190272190271

[george wilson]

I would always opt for a good brand old saw. Even from the 50's is too late. The turn of the century or earlier will have better spring steel in them. We had a bunch of Garlick saws in Wmsbg. Before I became toolmaker,they used to buy them without handles and make handles for them. They were soft as butter. And,they were ground incredibly rough!!! No using their shiny plates to check for squareness!! There were several in the Cabinet Shop. I would not use them.

[Rob Streeper]

I recently acquired an Ames 2-S hardness tester. This tester measures superficial hardness on the Rockwell N and T scales. It is specifically designed for measuring the hardness of thin materials. In the process of using this tester on a number of saws I own, both old and new, I found some very interesting results. Here's the data and statistics.
303979

The first table is for various samples of 1995 steel, commonly used by boutique saw makers. The second is data derived from testing of the products of three boutique saw makers. The third table is data from testing of a number of older Disston saws that I own. The last table presents the results of the statistical analysis of the data in tables 1 to 3.

The conclusions I draw are:

1) 1095 steel is a consistent product. Despite the fact that the test materials were purchased from different sources over a period of several years the hardness values for the products were all very similar with a remarkably low standard deviation of 0.34 Rc points. Plus these tight results show you that both my technique and my hardness tester are working well.

2) Of the custom makers, only one is using the equivalent of 1095 steel. The other two makers represented in my collection are using softer material. Maker 3 is using very soft metal, 40% softer than 1095, - likely because it's cheaper and/or easier to work with. Maker 2 is using something that is about 7% softer. The highly significant t values (t < 0.05) for these measurements indicate a high degree of confidence that the measurements are not due to chance.
Maker 2's saws work just fine for me, but I'm not using them for production work.

3) Disston's products varied in hardness over the years. The Disston saws in my collection were manufactured in the period spanning from post WW1 to post WW2. The variability is not too surprising because the concepts of industrial quality control were in their infancy in the early 20th century. Disston also used steel that is harder by just under 4%, or about 2 Rc points, than is 1095 but the difference is on the edge of statistical significance (t = 0.04).

Further, modern custom saws made with raw 1095 steel are not as hard as are older Disston saws. If the plate hardness is important and if Disston optimized his products we've actually taken a step backward in our unquestioning use of 1095.

[george wilson]

Are you really sure of the readings for the old Disston D8's and #4 in your chart? at 58 Rockwell C scale(I know you said your tester did N scale and T scale,but your results for 1095 steel are very close to the very consistent 52 RC I got from the 1095 I bought) ? It would not be possible to file saws that hard,and they would be so brittle as to snap off very,very easily,IF they were C scale numbers.

Are you aware that there are 3 different N and T scales? And,they are for specific types of steels,cast irons,and other materials? For example,there is a 15N,30N and a 45N scale. Differing T scales too.

I haven't worked with the N and T scales,so I really don't know what I'm looking at here.

[Rob Streeper]

Hi George,

Yes, I know about the different scales. The tester came with two calibration blocks and the readings were dead on despite the fact that the documents in the box indicated that it was produced in 1969.
I measured the hardness of each saw plate by removing the handle and testing the bright steel there after solvent cleaning. I made no special effort to polish the steel. On the Disstonian institute discussion of saw steel there are some hardness testing results but the values reported were for test points were near the teeth. It is also written there that the hardness measured was higher under the handles. I suspect that the roughness that is naturally to be expected in the region of the teeth caused the measured hardness readings to be low. Another possibility of course would be that the steel in the area of the teeth is softer, but why do that? I know that Disston hammer tensioned and tempered their plates but I've never read anything detailed about their procedures.

Cheers,
Rob

[Rob Streeper]

Please post responses to this thread: http://www.sawmillcreek.org/showthread.php?226091-Hardness-testing-of-saw-plates
Another member suggested I start an independent posting for this subject.
Thanks,
Rob

[Rob Streeper]

Okay, here is some more data. In a nutshell I took two pieces of 1095 0.035" thick and did some testing on them. The hardness of the first piece was measured in it's factory state - bluing and all. The other larger piece was divided into two roughly equal sections. One section was hammered on an anvil. Then both sections were ground just enough to remove the bluing. Then I did N45 testing on all three, fifty tests on each specimen for a total of 150 measurements. Here is the data and the first set of derived stat's. I've posted a full analysis of these results here at post #103: http://www.woodworkforums.com/showthread.php?t=182165&page=7

304235
304236

[David Weaver]

One would assume that the hardness difference is superficial, or the 1095 would lose its spring at 60 hardness.

Presuming you have coil at the thickness of carpenter saw plates, it would be instructive if you could find someone with a C tester to strike the same hammered areas you've tested with a superficial tester and converted to C values.

Hammering will likely have the same effect on a device created for superficial testing as would case hardening, and any rolling or hammering that was done to tension saw plates would've been done to increase tension, but not to increase through and through hardness, or the saw plates would've lost their spring and snapped.

[Rob Streeper]

304304304305304306304307304308304309304310
Same samples of 0.035" thick 1095 analyzed above on the N45 scale tester were analyzed here on the 150kgf Rockwell C scale tester. The results for each testing method are within the standard deviations.

[george wilson]

Since the available spring steel,I am told by a very reliable source,is now coming from India,and subject to varying quality and hardness,it might not be really meaningful to attempt to put down figures for the hardness of spring steel.

I am glad I'm as old as I am,since the World is suffering from a decline in many things I value. Things like good files,good spring steel,good mahogany to name a few.

[Patrick McCarthy]

"is not coming from India" . . . . .George, did you mean " is NOW coming . . " ??

[george wilson]

Sorry,typo. Wife was using a recipe on the computer and I was rushed. So the answer is Oh yes indee-de.

[Rob Streeper]

Since the available spring steel,I am told by a very reliable source,is now coming from India,and subject to varying quality and hardness,it might not be really meaningful to attempt to put down figures for the hardness of spring steel.

I am glad I'm as old as I am,since the World is suffering from a decline in many things I value. Things like good files,good spring steel,good mahogany to name a few.

George,

I wouldn't be surprised to learn that. The steel from different lots does seem remarkably consistent. I know ISO QC procedures are widely adhered to but it is surprising that there's not a little more spread. Sorry if I irritated you - that was never my intention. Controversial results always stir strong emotions, that's why I went to the efforts that I did so that I could make as good a case as my means allow.

Thanks,
Rob

[Joel Moskowitz]

While there might be some 1095 coming from india, i assume that what you mean by "spring steel" stuff comes from all over and in many qualities. there is even a1095 rolling mill in NJ. sandvick is a big supplier too. i dont thin i have even seen samples of 1095 that would lead me to suspect india. so don't give up hope.

[Rob Streeper]

While there might be some 1095 coming from india, i assume that what you mean by "spring steel" stuff comes from all over and in many qualities. there is even a1095 rolling mill in NJ. sandvick is a big supplier too. i dont thin i have even seen samples of 1095 that would lead me to suspect india. so don't give up hope.

Hi Jim,

I've been sourcing Lyon brand steel from Zoro tools. Relatively recently they started selling it in a very wide range of sizes in smaller quantities.

Rob

[Tony Zaffuto]

Some comments: ISO stipulates documentation developed by the company seeking certification, must follow a standardized order, but not the methodology used. Further, the quality of the underlying company is only as good as the registrar that audits the company to determine compliance to the standard. A company can be ISO registered and not have any procedure in place that describes use of hardness testing, let alone specifying hardness scales, or selection of proper equipment to the material to be tested.

As far as hardness testing, variability in readings can happen and again is determined by the consistency of the operator's methods as well as the equipment itself (not to mention proper use).

I am not a QC tech/QC manager/Director of Quality or any other title associated with the quality department in the manufacturing plant I own, though we do have a dedicated quality lab, with 4 employees administering our quality program and directives (in excess of 70% of our sales output goes into new cars).

[Kees Heiden]

I just did a simple test. I have a small piece of 1095 steel, 0.6 mm thick. One side I hammered with a 600 gram hammer on an anvil. The other side was left as it was. Then I took a file and filed small triangles in the sides of the piece, 20 file strokes per attempt.

First, the feel. The first strokes on the hammered side feel a little bit harder, but I don't know if that feeling would be reproducable in a blind test. Further down I am not able to feel any difference.
Then measuring the depth of the triangles. I can't really measure any difference. Some times the hammered side goes a little deeper, sometimes the other side.

Conclusion: I am not really able to feel much difference between hammered and unhammered springsteel. And the file dives into the steel just as fast.

[David Weaver]

Conclusion: I am not really able to feel much difference between hammered and unhammered springsteel. And the file dives into the steel just as fast.

That being because Rob is using a tester that tests surface hardness, apparently. If you were using 1095 and increased the hardness five points, you would be able to tell when filing.

Thanks for doing that test for us, it confirms my earlier comments.

[Kees Heiden]

In the last test Rob is using a real Rc tester.

My quick little test obviously doesn't really proof much. It proofs mostly that I don't have very sensitive fingers.

[David Weaver]

Controversial results always stir strong emotions, that's why I went to the efforts that I did so that I could make as good a case as my means allow.


Let's examine why that is. Here's a quote from your first post:

Further, modern custom saws made with raw 1095 steel are not as hard as are older Disston saws. If the plate hardness is important and if Disston optimized his products we've actually taken a step backward in our unquestioning use of 1095.

The entirety of the "controversy" is over that incorrect quote and the data that you've suggested that proves it. You have tested old saw plates under the handle, but not at the tooth line. Subsequently you admitted those saws can be filed, which proves (whether you like it or not), that they are softer than the 58 values you show in your table (substantially so unless you can only file a few teeth before ruining a file), and you stated that you wouldn't damage your saws by striking the tooth line.

The tooth line is where the hardness matters.

What you have done is akin to striking a chisel at a tang or a plane iron at the wrong end, then proving that there's little variability between your strikes at the wrong end and then declared something about plane irons based on those statistics.

I have offered to help you find some vintage saws that you can strike at the tooth line, and I have not heard anything back from you. Your conclusion will change because people have studied this before, including the old tools list individual who struck saws with a C tester under the supervision of an engineer who uses the same device.

You have not reconciled with the fact that your conclusions is either wrong (if the data strikes are not accurate due to a limitation with your tooling testing surface hardness) or misleading (suggesting that a saw that might be overhard under the handle but not at the tooth line provides relevant data for your conclusion if you choose to take the higher value under the handle).

I am challenging you to get it right, as you state that you have done the best you can, but that is not true. Doing the best you could would be guarding the quality of the data that you're sampling in the first place, and taking strikes under the handle of a saw is not your best effort.

Since it is already well known that vintage saws are not harder than 1095 that is shipped in the 50 hardness range, I will continue to challenge you until you either understand why the data isn't useful and your conclusion is misleading (and certainly casts aspersions on folks like ron bontz and others who make fine saws - none of whom I have ever bought a saw from nor do I have any relationship to) and admit that it is, or you do something to get a more relevant reading, and then incorporate that into drawing a conclusion.

[Rob Streeper]

Some comments: ISO stipulates documentation developed by the company seeking certification, must follow a standardized order, but not the methodology used. Further, the quality of the underlying company is only as good as the registrar that audits the company to determine compliance to the standard. A company can be ISO registered and not have any procedure in place that describes use of hardness testing, let alone specifying hardness scales, or selection of proper equipment to the material to be tested.

As far as hardness testing, variability in readings can happen and again is determined by the consistency of the operator's methods as well as the equipment itself (not to mention proper use).

I am not a QC tech/QC manager/Director of Quality or any other title associated with the quality department in the manufacturing plant I own, though we do have a dedicated quality lab, with 4 employees administering our quality program and directives (in excess of 70% of our sales output goes into new cars).

Hi Tony,
Yeah, I know about the issues with Quality Systems. I once heard someone say that, if a company made life preservers out of bricks, the only thing that the quality system would do would do is ensure that the bricks were all of uniform size and weight.
Hardness testing is fraught with complications, that's why the NIST best practices guidances suggest the testing procedures that they do. That variability and uncertainty is precisely the reason that I have used my efforts to produce what I have posted here and on the Woodwork Forums.
Disston's 52 has been discussed a lot but tested very little. There is a little information available on the web but I haven't found anything with the rigor of my study. I know my work here has limitations but I argue that some information is better than virtually none.
I've taken a lot of heat over my refusal to reveal the identity of Maker 3 but I think my reasoning is sound. I'm not out to damage anybody's reputation but I do feel that the saw making community can do better and I do feel that the saw consuming community needs to be warned to be careful. This problem is not by the way the only problem I have found in custom saws, a couple more have come to light.
My feeling is that a manufacturer has a duty to meet customer quality expectations no matter how small the manufacturer might be. Hidden defects are a big problem and nobody will find them without doing some testing.
One other poster said that he had observed inhomogeneities in a particular roll of saw blade steel he had. I think that information should come as a warning to everybody who makes saws for sale at the very least. If there's a problem with the raw material stream we should all be testing somehow be it with files alone or real hardness testers like I have used. Otherwise the buyers of these saws may decide that we don't really care about them.

Cheers,
Rob

[David Weaver]

In the last test Rob is using a real Rc tester.

My quick little test obviously doesn't really proof much. It proofs mostly that I don't have very sensitive fingers.

Ahh, I missed that comment at the end. I'm not sure what it proves because I don't know if you hammer like rob hammers, or if your steel would still be easily fileable at any moderately increased hardness.

[David Weaver]

For comparison, the data that was provided in an "old tools" list around 1999 or 2000 from a C tester under the supervision of a professional (for anyone perplexed by the stanley results, note the irons are the laminated versions and not later versions):




Plane irons HRC
Record #7 T14 Tungsten steel, laminated 63.2
Stanley #4 SW laminated 62.6
Stanley #5 SW laminated 62.3
(Rev. Hock says 62 for his blades)
(LN states 60-62)

Saws
No.7 Disston Philada 48.5
D8 Disston Philada 44.0
No.12 Disston Philada 48.5
#4 Backsaw Disston Philada 48.9
Bow saw blade, no mark, 24 x 1 in. 52.0
(3 for $1.50, drive by...)
(LN Ind. dovetail saw suppose to be 52)

Chisels
Marple Blue Chip 58.8
TH Witherby Warranted bevel edge 62.4
Stanley #720 60.8

#66 beader blades
orig. Stanley reeding 54.5
LN router blade 62.0

#45 blades 62.1-63.2
#46 blades 63.5-63.7

EC Atkins No.5 scraper blade 51.4

(and a link to that whole archived discussion)

http://swingleydev.com/archive/get.php?message_id=63868&submit_thread=1

[Rob Streeper]

Let's examine why that is. Here's a quote from your first post:


The entirety of the "controversy" is over that incorrect quote and the data that you've suggested that proves it. You have tested old saw plates under the handle, but not at the tooth line. Subsequently you admitted those saws can be filed, which proves (whether you like it or not), that they are softer than the 58 values you show in your table (substantially so unless you can only file a few teeth before ruining a file), and you stated that you wouldn't damage your saws by striking the tooth line.

The tooth line is where the hardness matters.

What you have done is akin to striking a chisel at a tang or a plane iron at the wrong end, then proving that there's little variability between your strikes at the wrong end and then declared something about plane irons based on those statistics.

I have offered to help you find some vintage saws that you can strike at the tooth line, and I have not heard anything back from you. Your conclusion will change because people have studied this before, including the old tools list individual who struck saws with a C tester under the supervision of an engineer who uses the same device.

You have not reconciled with the fact that your conclusions is either wrong (if the data strikes are not accurate due to a limitation with your tooling testing surface hardness) or misleading (suggesting that a saw that might be overhard under the handle but not at the tooth line provides relevant data for your conclusion if you choose to take the higher value under the handle).

I am challenging you to get it right, as you state that you have done the best you can, but that is not true. Doing the best you could would be guarding the quality of the data that you're sampling in the first place, and taking strikes under the handle of a saw is not your best effort.

Since it is already well known that vintage saws are not harder than 1095 that is shipped in the 50 hardness range, I will continue to challenge you until you either understand why the data isn't useful and your conclusion is misleading (and certainly casts aspersions on folks like ron bontz and others who make fine saws - none of whom I have ever bought a saw from nor do I have any relationship to) and admit that it is, or you do something to get a more relevant reading, and then incorporate that into drawing a conclusion.[/COLOR]

David,

I don't want to get into another battle with you. In my testing I've reported more data points than any other source that anybody here or on the Woodwork Forums ever has before. The reason that I haven't contacted you about taking the samples is that I'm not sure what your intentions are and I don't at this time want to give you my address. This is because you have been so vociferous in you denunciations of my data and I think somewhat unfair to me. If you continue talking to me reasonably, and I don't mean that you must agree with me, I may take you up on your offer.
I acknowledged the limitations of testing under the handles and in fact I was the first to point it out to the community - don't I at least get a little credit for having done so? In addition, I started the conversation about saw plate hardness despite the fact that I knew that there would be differences in opinion. There is really very little data on saw plate hardness available. More work needs to be done.
I just had another thought. I have a Disston No. 4 backsaw that likely was made some time in the WWII era. Were the blades of the backsaws hammer tensioned? Does anybody know? If not I could do C and N scale testing on that saw and report it. What do you think? The only data I have seen on a backsaw is presented at the Disstonian Institute in the discussion of saw steel and that saw was made in the 1800's and was reported to be very brittle.

Cheers,
Rob

[Rob Streeper]

David,

Let's discuss the tooth line issue for a minute. I agree that the teeth are 'where the rubber meets the road'. However there are some problems with testing very close to the teeth.

It's reported that Disston punched teeth and that will work harden at least part of the steel around the teeth. Setting also work hardens the teeth and the areas adjacent to them. I have no idea how far the work hardening extends but perhaps we'll get lucky and an expert will weigh in here.
A second problem with testing at the tooth line is that the metal is warped some due to the punching but also due to the setting. Warped surfaces will spring under the tester point and the readings will be incorrect. Warping causes the readings to come back falsely soft.
Another issue is the surface finish of the steel being tested. If you look at the surfaces of hardness testing blocks you'll see that they are very finely dressed. The reason they are dressed is that surface roughness will also throw the readings off. Rough surfaces also give back soft readings.
Ideally, we need to test a saw lacking set, something like a Disston 77, that has as close to a new finish as is possible. Unfortunately testing such a saw will ruin it's collector value.

We also don't have an appreciation for specifically where the Disston blades were work hardened. Was it an inch from the teeth, two inches, or just along the back of the plate? Does anybody know? I've read that they were worked along the back but the D-7 saw I have was tested in about the middle of the plate, albeit under the handle. I was able to test there because the handle extends so far down the back of the plate. The readings were still high.
The alternative is to take a saw that is in good shape, lacking corrosion, bends or any scratching and test it but I don't have an old Disston in that kind of condition.

I'll do some more on my Disston's and sample down the plate as far as I can and report the results while staying under the handles.

Cheers,
Rob

[Rob Streeper]

Ahh, I missed that comment at the end. I'm not sure what it proves because I don't know if you hammer like rob hammers, or if your steel would still be easily fileable at any moderately increased hardness.

David and Kees,

I purposely kept my hammering fairly light. If you look at the pictures I took of the back side of the test specimen of 1095 I posted on Woodwork Forums you can see quite clearly that the surface wasn't dented. However the distortion did extend all of the way through the plate, I wanted to show that and that's why I photographed the back side of the test sample. Heavier impact is a future study.

[David Weaver]

David,

I don't want to get into another battle with you. In my testing I've reported more data points than any other source that anybody here or on the Woodwork Forums ever has before. The reason that I haven't contacted you about taking the samples is that I'm not sure what your intentions are and I don't at this time want to give you my address. This is because you have been so vociferous in you denunciations of my data and I think somewhat unfair to me. If you continue talking to me reasonably, and I don't mean that you must agree with me, I may take you up on your offer.
I acknowledged the limitations of testing under the handles and in fact I was the first to point it out to the community - don't I at least get a little credit for having done so? In addition, I started the conversation about saw plate hardness despite the fact that I knew that there would be differences in opinion. There is really very little data on saw plate hardness available. More work needs to be done.
I just had another thought. I have a Disston No. 4 backsaw that likely was made some time in the WWII era. Were the blades of the backsaws hammer tensioned? Does anybody know? If not I could do C and N scale testing on that saw and report it. What do you think? The only data I have seen on a backsaw is presented at the Disstonian Institute in the discussion of saw steel and that saw was made in the 1800's and was reported to be very brittle.

Cheers,
Rob

My intentions are simply to get you saw plates that you could strike in a relevant area (halfway up the plate? An inch above the tooth line?). I'd have no interest in any of this if striking under the handle gave you relevant or meaningful data, but it doesn't. You are fascinated with statistics for empirical data sets, and I assume that you use a software package in your work, and thus the familiarity. Your example about bricks is suitable here, You're effectively measuring the straps on a lifejacket to see if it floats. When I have asked you questions about following why the hardness under the handle doesn't create a meaningful dataset, you have responded with comments about the empirical statistics, which completely misses the point. I am formally educated in statistics, that's not where the problem with your results and your conclusion are (they are in the collection and conclusion drawn from the data, not in the use of the data after it's collected).

I literally only have interest in you getting meaningful numbers and not making misleading statements. We have at least two people who have measured saws with C testers in professional labs, and both get similar results and they are not similar to yours. Your brick comment comes in again when that is the result.

Disston backsaws are similar hardness to their large saws. I have filed many, and most are not defective like the one in the disstonian institute page. I have encountered only one like that (a jackson branded saw made by disston that isn't very hard but breaks when the teeth are set anyway). The saws of vintage age that I have found to be softer are very old english saws - like 200 years old (though that may not be universally true) - and some later low price examples (a barber and genn saw I have is soft, but not unusably so).

My offer still stands to provide you (or coordinate people providing to you) sawplates that you can strike to get relevant data. I gathered early on that you are resistant to getting meaningful data because it will change your conclusion, especially now that you are this invested in defending the information you provided (which aside from the strikes under the handles of vintage saws seems to be reasonable). But the offer stands. Your study will have no credibility in regard to that conclusion until you correct it.

(the part about it being possibly dangerous for me to have your mailing address is humorous)

[Rob Streeper]

My intentions are simply to get you saw plates that you could strike in a relevant area (halfway up the plate? An inch above the tooth line?). I'd have no interest in any of this if striking under the handle gave you relevant or meaningful data, but it doesn't. You are fascinated with statistics for empirical data sets, and I assume that you use a software package in your work, and thus the familiarity. Your example about bricks is suitable here, You're effectively measuring the straps on a lifejacket to see if it floats. When I have asked you questions about following why the hardness under the handle doesn't create a meaningful dataset, you have responded with comments about the empirical statistics, which completely misses the point. I am formally educated in statistics, that's not where the problem with your results and your conclusion are (they are in the collection and conclusion drawn from the data, not in the use of the data after it's collected).

I literally only have interest in you getting meaningful numbers and not making misleading statements. We have at least two people who have measured saws with C testers in professional labs, and both get similar results and they are not similar to yours. Your brick comment comes in again when that is the result.

Disston backsaws are similar hardness to their large saws. I have filed many, and most are not defective like the one in the disstonian institute page. I have encountered only one like that (a jackson branded saw made by disston that isn't very hard but breaks when the teeth are set anyway). The saws of vintage age that I have found to be softer are very old english saws - like 200 years old (though that may not be universally true) - and some later low price examples (a barber and genn saw I have is soft, but not unusably so).

My offer still stands to provide you (or coordinate people providing to you) sawplates that you can strike to get relevant data. I gathered early on that you are resistant to getting meaningful data because it will change your conclusion, especially now that you are this invested in defending the information you provided (which aside from the strikes under the handles of vintage saws seems to be reasonable). But the offer stands. Your study will have no credibility in regard to that conclusion until you correct it.

(the part about it being possibly dangerous for me to have your mailing address is humorous)

Let me reassure myself for a while and I'll reconsider your offer.

To a degree you're right when you point out my reliance on empiricism. I am employing the tools and techniques I have to try to understand an issue that appears to be much discussed but which has really not been subjected to much in the way of systematic inquiry. I'll keep posting my results, warts and all, because I think it's necessary to supplement the scant information available on this subject.

[David Weaver]

Let me reassure myself for a while and I'll reconsider your offer.

To a degree you're right when you point out my reliance on empiricism. I am employing the tools and techniques I have to try to understand an issue that appears to be much discussed but which has really not been subjected to much in the way of systematic inquiry. I'll keep posting my results, warts and all, because I think it's necessary to supplement the scant information available on this subject.

The fact that there's little data makes it even more important that it's accurate.

if the old saws are indeed harder (in a usefully measured area), then that is a fairly big deal. If they are not and the data suggests they are because it's from irrelevant areas on saws, or because the sample size is too small, that's a very large problem.

We have two data sets other than yours. George provides a range from his strikes. It's still data even if he didn't supply it in a spreadsheet. The data also on the old tools list is in line with what george provided (and they are not related items, so there is independence in measurement). That poses a real problem.

I don't think you should stop providing data, I just think it needs to be corrected so that what is collected in line with the conclusions that are drawn from it. If your means are limited, or striking your own saws at the teeth is a real problem, let me know once you're comfortable, and I'll buy one of the "opportunity lots" on ebay, label the plates and take off their handles (I could probably use the saw nuts, anyway) and send the plates in a flattened mailing tube. It will be much easier to send a half dozen or so without the handles, anyway. I believe I have two from my own stock that could be used for this, though I may have thrown the plates away in the past. I'll have to check - even if i don't, it is easy to come by more top line saws that have problems that make them duds for a user, but perfect candidates for your data collection.

[Rob Streeper]

The fact that there's little data makes it even more important that it's accurate.

if the old saws are indeed harder (in a usefully measured area), then that is a fairly big deal. If they are not and the data suggests they are because it's from irrelevant areas on saws, or because the sample size is too small, that's a very large problem.

We have two data sets other than yours. George provides a range from his strikes. It's still data even if he didn't supply it in a spreadsheet. The data also on the old tools list is in line with what george provided (and they are not related items, so there is independence in measurement). That poses a real problem.

I don't think you should stop providing data, I just think it needs to be corrected so that what is collected in line with the conclusions that are drawn from it. If your means are limited, or striking your own saws at the teeth is a real problem, let me know once you're comfortable, and I'll buy one of the "opportunity lots" on ebay, label the plates and take off their handles (I could probably use the saw nuts, anyway) and send the plates in a flattened mailing tube. It will be much easier to send a half dozen or so without the handles, anyway. I believe I have two from my own stock that could be used for this, though I may have thrown the plates away in the past. I'll have to check - even if i don't, it is easy to come by more top line saws that have problems that make them duds for a user, but perfect candidates for your data collection.

David,

Sounds fine to me. I've thought of a way to receive them. I don't know you yet and I feel the need to be careful.

I had a laser pointer incident recently. The responding police officer told the person who pointed the laser that, if the laser had been pointed at him, the holder of the laser pointer would have been shot. Never hurts to be careful you know?

As to your proposal, here is a picture of the surface of a hardness standard. I realize that finding a cheap old Disston with this kind of finish is going to be difficult if not impossible but we want something as close to this as is reasonable. I can of course grind and lap the surface of a blade but that will result in the readings being lower than the true hardness of the blade.

304343

If and when you find something send me a PM and post the pictures here so all can comment on the design of the testing strategy. Once we have a consensus I'll PM you an address. Then I'll do the testing as agreed and report the results here. In the meantime I'll tweak up my B/C tester to increase the linearity and work out some of the intercept offset I have now. Perhaps you could get somebody else from the forum to do some parallel testing on the same plates and then send them to me, or send them to me first and I'll send them to the next tester?

[David Weaver]

Why do it? Because if the saws are too hard to file, workmen would've been ruining very expensive files back then. Saw shops would probably also refuse to file overhard saws. If you sent a 58 hardness saw to a saw shop (58 at the teeth) with any considerable amount of wear (supposing it wouldn't have broken teeth from trying to set it at that hardness), they wouldn't sharpen it for you, or they'd charge you for files used. An easy remedy is to find old saws that were not pitted and joint off the teeth with a bastard file. If there is any scale at the surface (but no pitting) that could easily be stoned off for a spot to test.

I think if the disstonian institute saws were rusty or pitted near the toothline, they would've noted that. Most saws that have not seen pitting do not have roughness near the teeth.

[Rob Streeper]

Why do it? Because if the saws are too hard to file, workmen would've been ruining very expensive files back then. Saw shops would probably also refuse to file overhard saws. If you sent a 58 hardness saw to a saw shop (58 at the teeth) with any considerable amount of wear (supposing it wouldn't have broken teeth from trying to set it at that hardness), they wouldn't sharpen it for you, or they'd charge you for files used. An easy remedy is to find old saws that were not pitted and joint off the teeth with a bastard file. If there is any scale at the surface (but no pitting) that could easily be stoned off for a spot to test.

I think if the disstonian institute saws were rusty or pitted near the toothline, they would've noted that. Most saws that have not seen pitting do not have roughness near the teeth.

Here's a lot of Disston's for sale. A couple look pretty decent at first glance. http://www.ebay.com/itm/L1322-VINTAGE-HAND-SAW-LOT-OF-TOOLS-WOODWORKING-Disston-Etc-/381117154823?pt=LH_DefaultDomain_0&hash=item58bc5a4607

[Kees Heiden]

I am a bit far away for logistic help but I can easilly paypal 20 dollars for the cause. I am curious too. When you two have got a deal, then send me a pm.

[David Weaver]

Yes, that looks like a decent set. It will take a little stoning or sanding to get a clean spot on a couple of them, but that's not terrible, and many of those are D8s, so they are first line saws.

I don't know that I've noticed much difference in hardness on second line saws (admittedly I haven't filed many), but the second line saws that look good are often lacking in tapering and tensioning, making for sort of a flat fat floppy saw plate.

There's no great rush, so if someone decides they really want that lot of saws for $100, I'm not going there, but we will get something relatively soon that will work.

I wonder if any of the folks who read this forum and flip tools would be willing to pony up a few damaged (but not pitted rust) plates if I pitched in a few bucks. They could send them to you, then.

[Rob Streeper]

Yes, that looks like a decent set. It will take a little stoning or sanding to get a clean spot on a couple of them, but that's not terrible, and many of those are D8s, so they are first line saws.

I don't know that I've noticed much difference in hardness on second line saws (admittedly I haven't filed many), but the second line saws that look good are often lacking in tapering and tensioning, making for sort of a flat fat floppy saw plate.

There's no great rush, so if someone decides they really want that lot of saws for $100, I'm not going there, but we will get something relatively soon that will work.

I wonder if any of the folks who read this forum and flip tools would be willing to pony up a few damaged (but not pitted rust) plates if I pitched in a few bucks. They could send them to you, then.

That would work fine. I really do suggest that we try to find somebody to do some C scale testing in parallel with mine and if possible and appropriate based on plate thickness some N scale testing would also be interesting.

[David Weaver]

That would work fine. I really do suggest that we try to find somebody to do some C scale testing in parallel with mine and if possible and appropriate based on plate thickness some N scale testing would also be interesting.

I think if the discussions go on long enough, someone will come forward, though we're only going to be able to do it on the big saws with enough plate thickness (that's OK). My friend changed jobs and I lost my ability to hand things to him to take to the lab at his work. I never even thought about having saws tested back then, we were interested only in chisels and plane irons, but interested enough even to strike japanese chisels.

[Rob Streeper]

I think if the discussions go on long enough, someone will come forward, though we're only going to be able to do it on the big saws with enough plate thickness (that's OK). My friend changed jobs and I lost my ability to hand things to him to take to the lab at his work. I never even thought about having saws tested back then, we were interested only in chisels and plane irons, but interested enough even to strike japanese chisels.

It would be nice if we could. I've got a Beverly #3 shear that cuts saw plates like they're made of paper. I could cut up the blades and re-mail pieces to a number of different people to test.

[John Stankus]

I checked with my buddies in engineering and have access to a Newage ME-2RDB Rockwell hardness tester. This is the sister instrument to the Versitron that George used (same test, a little less automated).

Just so everyone understands how Rockwell hardness testing works, I'll run through my understanding of the process.

Rockwell hardness testing works by measuring indentation of a material by an indenter which depends on the scale and can be a hardened ball or a diamond.
The indenter is preloaded with a specific force on the sample and is allowed to come to equilibrium. Then a test load is applied that idents the material under test. The load then returns to the preload value. The difference between the zero point with the initial preload and the depth after returning to the preload value is inversely proportional to the hardness. (harder will have less penetration).

There are some measurement issues with this depending on thickness and how close to an edge you may get. Since the indentation deforms the material, the convention is that you need a sample at least 10 times as thick as the indentation. This means that for thin material it must be harder than a particular value for the test to be accurate regarding the scale. It may be acceptable for direct comparisons between materials of the same thickness, but relating to bulk scale can be problematic. One reference I saw gave the thought experiment of measuring the hardness of a cigarette paper (hey it was an older reference), you would see mostly the hardness of the anvil in the instrument. This may be where some of the issues with the discussion of Rob's data lies. Some of the fancier (i.e. Versitron) machines can interconvert between scales and use appropriate loading based on thickness. If the loading is excessive for the thickness it might be measuring the composite of the sample and the anvil. The other issue is measuring near the edge, since the material may deform and flow under load. There are some conventions as to how far from the edge is appropriate.(I need to look those back up)

As someone who teaches how to make measurements (granted in a chemical setting rather than mechanical) we also need to be careful about our sampling strategy. Are we picking a representative sample that is typical and relevant. I understand the desire to do the testing under a handle where it may not be seen, but I imagine that the blades were probably held by that area when heat treating, so the thermal history may be different than along the tooth line.

I guess the one question I have is what is the range of plate thicknesses are we talking about?

I will try to make some arrangements to go and check out the instrument, and perhaps I'll grab a selection of plane blades to test to make sure I know what I am doing without worrying about thickness. And then I'll have a better feel for what I can test.

John

[Tony Zaffuto]

My suggestion would be comparison testing against a known standard, with the standard shipped from one tester to the next, along with the samples. As far as differences in hardness, along the saw plate, what will affect readings will be what has been done to the saw plate after shearing from coil stock, for example, was the plate taper ground? Was the plate sanded by one of the "boutique" saw makers to approximate taper grinding of old? Is everyone here aware of tolerance ranges acceptable for hardness readings? (in my industry-powdered metal, apparent hardness on the Rc scale is +/- 5 points; I cannot answer tolerance range for particle hardness tolerances, though the numbers should be readily available in say, a volume of "Machinery Handbook").

I have no desire to get involved in any testing unless variables are identified in advance and minimized. Additionally, what is the point of the tests?

[george wilson]

I wonder what the point is too. I have done it for so long that I can give a pretty accurate guess at the RC of a saw by filing with a new,fine cut quality file. I got good at picking out the most durable antique bitted plane irons also,from many years of using them on a daily basis.

I understand 1070 spring steel is available from India,at 52 RC,while the 1095 is more like 48 RC. Why this is,I don't know. Hardness by itself is not the end all and be all,though. 1070 steel at the higher hardness will not have the carbon content to have particularly good wear resistance. The best combination would be 1095 at the formerly usual 52 RC.

The same sort of thing applies to chisels. Vanadium content steel chisels can be hard,but some do not like them.

So,all these tests may or may not have real relevance. What is needed also is the chemical analysis of the steel involved. It would not necessarily be of value,with the mix of spring steels now on the market,for a custom maker to even guarantee the hardness of his saws. I would not care for the 52 RC 1070 steel,for example. But,that might be what you were getting. The country of origin would also have to be guaranteed. Then,who would prove it?

Some good spring steel can still be had from Austria if you pay the higher price for it. If I wanted to get back into saw making,I'd opt for the Austrian product. Or,an American product if available. I haven't bought spring steel for a long time,since we had to buy a high minimum purchase in the first place,we had a good stock pile. I had to buy the .042" steel 12 1/2" wide to get enough width to make proper Kenyon style crosscut and rip saws. We paid a cut off fee for every gauge also. I couldn't get 12 1/2" wide .042 spring steel in the available small packages of 6" wide blue shim material.

John,My Versitron hardness tester was a manual one,not the latest model by any means. I would pull the handle forward to indent the diamond into the steel,then let up on the handle till the needle stabilized at the RC number the steel represented.

Being in a museum,I had access to Federal surplus equipment. I got this valuable tester for $50.00 because they did not know what it was,and were too lazy to research it. It was the best surplus bargain I ever made.

On the other hand,they would try to sell WELDED bandsaw blades for just about retail,when you didn't even know their length,or in many cases,exactly what the blades were made of:Welded on HSS teeth,for example. They let a couple of 10' tall stacks of white pine shelving wood sit outside until it,over the years,turned into tired little heaps of brown rot. They would put things outside if they didn't get the price they wanted in a certain length of time,and just let them rust away to nothing. Would they REDUCE the price? NO. They'd rather let the stuff rot.

[David Weaver]

I've got two plates that can be struck. One is a 1900 or so (perhaps a little before) d8 that has been sharpened its share.

The other is a #7 (shown with no handle, I have the handle and thus know what it is) that is dark, but both are fresh enough to be struck for sure.. The 7 has not been sharpened too much, but it's an old saw that I purchased years ago for $20 on ebay. It was the very first saw I sharpened almost a decade ago (before I knew what I was supposed to do) and the teeth would need major reshaping just for me to sell it for a pittance, and I've go no interest in that. It is perfect for this purpose, because it's been filed (I don't think the bottom one has by me, but it's clear it has by plenty of other people, and it's got no broken teeth).

304359

I don't know what the point is too much other than getting relevant readings at the teeth of the saw. I think we'll be able to do that with this exercise, with proven era saws (not too late, not too early) and with no financial risk.

I can joint the teeth off of these plates before I send them.

[Larry Frank]

WOW...there is a whole lot going on here. If I were going to do a study like being suggested, I would do some things first.


One would be to make absolutely certain that everyone who is interested is comfortable with where the testing is going to be done. To figure this out, one needs to be pretty certain about exactly how the saws were produced and the thermo-mechanical processing of the saws. You want something as close as possible to the teeth and yet not be in the area where there may be uneven work hardening from the straightening or tooth setting or anything else. (in reality, does it really make any difference what the hardness is except on the actual tooth of the saw.)
As mentioned, you need to make certain that the surface condition of all the samples is the same.
I would want a chemical analysis of each saw being tested. Yes, I know that they are supposedly 1095 but the range in chemistry for this grade is quite large...Carbon 0.90 to 1.04%, Mn 0.30 to 0.50%, the level of silicon is not specified. This range of chemistry could make a difference in hardness. The ability to run accurate chemical analysis 50-100 years ago was not all that good which means that the steel maker was doing the best he could but there was a lot of variation of chemistry.
If you test newer saw blades, do you even know what the grade of steel is? If I was looking to make saw blades today, I would take advantage of some different grades of steel to get better properties.


To do this right, there is a large investment needed in time and resources. It is not a simple thing. Is all of this worth it other than a point of interest. As I reread this thread and the other one, I find myself coming back to what George Wilson and others said is that they could tell a good blade by the way it filed. Not very scientific but probably the most useful comment in the entire thread.

[george wilson]

Not very scientific,true,but the human brain is still the most sophisticated computer out there. Provided it has a proclivity for the work involved,and gets enough practice and exposure to develop good sensory judgements. That was a mouth full!! The proclivity part is very important. I have seen craftsmen with huge amounts of years under their belts who were still not particularly good. Some never could learn to design well in a lifetime or two. Even if he had a very refined English accent (a commodity too highly thought of amongst the curatorial types in the museum.)

And,then there is another vital ingredient: The passion to do something with your talents. But,that is getting into a whole other field. I have seen some young people with tremendous potential who just did nothing but get into trouble,do drugs,sell drugs,steal things,and likely who would have ended up in jail once they were on their own. Or some others I TRAINED (fortunately not too many),who drifted into mundane jobs just for the security of them,forgetting about talent I saw that they had. But,the smartest one I ever trained did that. Ending up as a civil servant,interviewing people for jobs. Waste,waste,waste. I hate to see such waste.

[Rob Streeper]

Well, let the debate begin.

At first thought I would suggest that the plates be cleaned if not polished on both sides by an agreed method. This can be all or most of the surface or in patches. Chemical, mechanical or abrasive cleaning or no cleaning at all? I suggest this be done by one person, somebody who has expertise in preparing materials of this type for the testing we envisage. Areas unsuitable for testing should be determined and clearly marked so that they are not tested.
Then I suggest that we agree on selections of regions to be tested - heel to toe at three or four distances from the tooth line for starters.
Whatever the matrix size and dimension I then suggest that the plates be ruled with some kind of non defoming marking system, perhaps a paint marker.
Depending on how many participate in the testing we should decide on how many replicates each tester should do at each testing region across the saw plates.
A test block or two to be sent along with the saws is a good idea.
Each tester should perform an agreed number of replicate measurements of both the test block(s) and each coordinate of the plate assigned for their testing.
Somebody needs to collect the data from all of the testers, compile, analyze and report it. It would be best if at least two independent people could do this step to minimize the chances for Excel errors and so on.
Then the results should be posted here.
What do you think? Too complicated, too simple or have I overlooked some things?

[David Weaver]

I'd say you strike them first, I'd be glad to tape spots about an inch above the tooth line.

I can sand the surfaces clean (no burnishing will occur, no hardening, etc).

Just these first two saws would get your started without having to buy a junk lot. They are pretty much all I have that's disposable. Ebay may be of help to add another one later.

I don't think we need to know anything about the composition of the vintage saws, both of the ones i'm showing above are first quality models and not second line saws. I've put a file to one, and someone else to the other a LOT, so there's no reason to believe these two are defective.

Preliminary results should dictate whether or not anything additinoal is necessary, especially given that your 1095 strikes have been very consistent and in line with 1095 specs.

[Rob Streeper]

I'd say you strike them first, I'd be glad to tape spots about an inch above the tooth line.

I can sand the surfaces clean (no burnishing will occur, no hardening, etc).

Just these first two saws would get your started without having to buy a junk lot. They are pretty much all I have that's disposable. Ebay may be of help to add another one later.

I don't think we need to know anything about the composition of the vintage saws, both of the ones i'm showing above are first quality models and not second line saws. I've put a file to one, and someone else to the other a LOT, so there's no reason to believe these two are defective.

Preliminary results should dictate whether or not anything additinoal is necessary, especially given that your 1095 strikes have been very consistent and in line with 1095 specs.

I think sanding or lapping is preferable at this point to electrolysis, acid cleaning or other methods. Given that the plates may be taper ground we need to carefully select testing areas too.

[Kees Heiden]

Maybe do tests higher up the plate too? We don't know exactly what Disston did with their saws and a map of hardnesses might give us a clueto how they tensioned the plate.

There is allready chemical analysis of Disston saws on the Disstonian institute website.

[Tony Zaffuto]

Again, what is the point of the test? Is it to demonstrate the variability of hardness in vintage saws? Is it to test the variability of a string of hardness test operators?

If you want to learn the hardness of saw plates, simply find a person who will test the materials for you, using a tester that has been properly maintained and calibrated (ours is done quarterly), along with an operator must be familiar with the correct operation of the tester and depending upon the model of tester, selection of indent and weights (if needed). For the cost of postage and test blocks, a certified quality lab can probably provide you all of the readings you would want, but the question remains, what will be done with them? Is it simply to say "this vintage Atkins saw, with "Silver Streak" steel, had a Rc value of 52 at the sharpened down toothline" and "this Disston #16, with "London Extra Refined" steel had an Rc value of 56 under the handle"?

I agree with a comment George made, in that he could tell the hardness of material when filing, though that came from years of experience. Since George has a hardness tester, maybe he can answer if he tested hardness on each saw before filing?

[David Weaver]

I think sanding or lapping is preferable at this point to electrolysis, acid cleaning or other methods. Given that the plates may be taper ground we need to carefully select testing areas too.

Rob, shoot me a PM with your address and I'll send these two plates to you after I sand them clean at the toothline. I'll send an area clean on both sides in the middle of the plates, too.

Send your work address if you're worried about giving out your home address.

[Rob Streeper]

Again, what is the point of the test? Is it to demonstrate the variability of hardness in vintage saws? Is it to test the variability of a string of hardness test operators?

If you want to learn the hardness of saw plates, simply find a person who will test the materials for you, using a tester that has been properly maintained and calibrated (ours is done quarterly), along with an operator must be familiar with the correct operation of the tester and depending upon the model of tester, selection of indent and weights (if needed). For the cost of postage and test blocks, a certified quality lab can probably provide you all of the readings you would want, but the question remains, what will be done with them? Is it simply to say "this vintage Atkins saw, with "Silver Streak" steel, had a Rc value of 52 at the sharpened down toothline" and "this Disston #16, with "London Extra Refined" steel had an Rc value of 56 under the handle"?

I agree with a comment George made, in that he could tell the hardness of material when filing, though that came from years of experience. Since George has a hardness tester, maybe he can answer if he tested hardness on each saw before filing?

Hi Tony,

Fundamentally I just want to know. By testing across the saw plates we'll produce information to inform the debate we've been having here. Much more importantly we'll have a benchmark, albeit for only two saws, that will help us understand how Disston used to produce saws. It is known that Disston hammered the saws but apparently nobody has a detailed idea of exactly where. Everybody knows that the saws can be filed which demonstrates that the teeth and some of the area around the teeth is in or close to the low 50's range of C scale hardness however nobody knows where the zones of hammered steel are. Are they just along the spine of the plate or do they extend to other regions? I'm willing to map these plates and try to throw some light on this issue.

Cheers,
Rob

[Rob Streeper]

David,

Sand the whole surface. I want to map them from tooth to back. A lot of work but I think the effort is worth it. I suggest using some wet-or dry and a thin hydrocarbon lubricant such as WD40 to help keep the surface uniform. I've found that sanding in this way produces a finer finish. In addition, I think that the teeth should be filed away. The reason is that the anvil of the C tester has a radius of about two inches. If I test close to the tooth line the points of the teeth will bear against the surface of the anvil because of the set and raise the saw plate above the anvil surface producing useless measurements. Let's get this agreed before you ship. PM sent.

I use these in my surface prep. Expensive but they last a long time if used with light oil. For lapping oil I use Rust Oleum spray on rust preventer. Home Depot stores in my area sell this in the spray paint section for some reason. It's not stocked with the other spray lubricants.

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[george wilson]

I do not have access to a hardness tester now. Since I do have a lot of experience by now,I don't feel like blowing a lot of money to buy a new one for my home shop use. I have an accurate electric furnace for when I make punches or harden knives,or whatever. I can harden and temper at accurately controlled temperatures and get the hardness needed for punches and dies for my wife's jewelry business. Beyond that,I'd mostly be making guitars,which need no testing.

Rob is where I was many years ago,when I was new to toolmaking and curious about many things including tool hardness. If he wants to dabble to satisfy his own curiosity,let him do so. Beyond that,I can't see him making Earth shaking new discoveries. The work already has been done even if charts and graphs were not drawn.

Charts and graphs in the end prove nothing. They,like computers,only reflect what has been put into them.Producers of nearly everything from tooth paste to medicine can make graphs to prove their product is best.

Being able to file a Disston saw proves nothing,especially that they are in the low 50's RC. They are more into the 40-48(at most) range( a nod to David). I'm sure exceptions can be found,but the ones I tested were in the 40-45 range. I guess I should have written a book or done a dissertation about it.:) It didn't seem that important at the time. Nor does it now.

[David Weaver]

David,

Sand the whole surface. I want to map them from tooth to back. A lot of work but I think the effort is worth it. In addition, I think that the teeth should be filed away. The reason is that the anvil of the C tester has a radius of about two inches. If I test close to the tooth line the points of the teeth will bear against the surface of the anvil and raise the saw plate above the anvil surface and thus produce useless measurements. Let's get this agreed before you ship. PM sent.

I'll sand them so that they're at least free of rust. They may be a little dark in spots, but they will be clean and full hardness. I'll joint the teeth off, too, I was going to do that just because there's no reason to have them other than initially to confirm that the plates don't have broken teeth (which could suggest a defect).

[Rob Streeper]

I'll sand them so that they're at least free of rust. They may be a little dark in spots, but they will be clean and full hardness. I'll joint the teeth off, too, I was going to do that just because there's no reason to have them other than initially to confirm that the plates don't have broken teeth (which could suggest a defect).

Check my post on the preceding page, I've added more suggestions.

[george wilson]

David,if Rob is so curious,let him sand the saws off.You've already been generous enough offering to spend your money buying and mailing them.

Wow,5 pages so far. Or,to be more accurate,64 posts. Reminds me of Shakespeare's play "Much ado about nothing".

[David Weaver]

Check my post on the preceding page, I've added more suggestions.

I'll sand them free of rust, but if you want them to be bright, you'll need to do that. I always sand with silicon carbide and WD40.

They'll certainly be fine for hardness testing. If you want to map them, you can use a white paint marker or score them with a carbide scribe.

[Rob Streeper]

I'll sand them free of rust, but if you want them to be bright, you'll need to do that. I always sand with silicon carbide and WD40.

They'll certainly be fine for hardness testing. If you want to map them, you can use a white paint marker or score them with a carbide scribe.

I'm okay with your proposal, would anybody else care to comment before we begin?

[David Weaver]

I'd be pleased if another couple of clean plates (perhaps with a kink or something, you could easily shear that out) that were disston and with no broken teeth would pop up.

2 is a good start. A sample of 5 would be better. I just don't have five to throw away.

[Rob Streeper]

I'd be pleased if another couple of clean plates (perhaps with a kink or something, you could easily shear that out) that were disston and with no broken teeth would pop up.

2 is a good start. A sample of 5 would be better. I just don't have five to throw away.

I agree, I'll keep an eye out locally. Garage sale finds here can be very good.

Here is some guidance on surface roughness. This isn't copyright marked so I'll post it in it's entirety. Different testing device but at least it gives an idea of how to prepare the plates.
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[george wilson]

I think this is called "Analysis paralysis."

[David Weaver]

that surface smoothness is no problem. Some darkness is left even at 220 or 400 grit, but I will probably sand them to 220 and a little finer in the spots where I think they should be struck.

My concern about the ebay lots (and why I put up two saws) is that a lot of the saws still have a lot of scale to remove, or are painted, etc. These two that I have will not take much work to be ready for striking.

[george wilson]

David: How the heck do you spell what I just posted?My spell check has stopped working. It is sulking in the corner since I clicked on it wrong.

[John Stankus]

Analysis paralysis (I need a support group for this :) )

[Rob Streeper]

The hard fact is that, as a researcher, you must be prepared to accept the results of carefully conducted experiments even if they do not fit your starting hypothesis or comport with your emotional desires. Rather in the spirit of this fable.


The Scorpion and the Frog

A scorpion and a frog meet on the bank of a stream and the
scorpion asks the frog to carry him across on its back. The
frog asks, "How do I know you won't sting me?" The scorpion
says, "Because if I do, I will die too."

The frog is satisfied, and they set out, but in midstream,
the scorpion stings the frog. The frog feels the onset of
paralysis and starts to sink, knowing they both will drown,
but has just enough time to gasp "Why?"

Replies the scorpion: "Its my nature..."

[george wilson]

I have a 9 pound sledge hammer I keep around here for swatting flies. But,I haven't used it yet.:)

I think you need to remember the part about your emotional desires yourself.

There are so many much better things to tie up your time with. Like,studying how to achieve good saw handle design. Something I have studied carefully because that is my nature.

[Rob Streeper]

I have a 9 pound sledge hammer I keep around here for swatting flies. But,I haven't used it yet.:)

I think you need to remember the part about your emotional desires yourself.

There are so many much better things to tie up your time with. Like,studying how to achieve good saw handle design. Something I have studied carefully because that is my nature.

At the moment I'm copying and thinking. Rome wasn't built in a day. Saws and more generally woodworking are interesting to me and they are areas where I am working to develop skills but they are not my calling.

In the area of my calling I have achieved, what is for me at least, lifetime success. This of course has nothing to do with the subject of this forum. Through many years of study and work and a decade of focused effort I have finally achieved something of significance that also has implications for all of us. I haven't done this alone of course because I stand in a way on the shoulders of those who labored before me. My personal efforts have been made in concert with others, one of singular import. Nonetheless even if no further successes accrue in the area of which I write here I will die contented knowing that my goal in life, i.e. to do something significant, has been achieved.

[george wilson]

A saw handle isn't exactly Rome.

[Pat Barry]

At the end of this effort, what is the result that is hoping to be achieved? Is it to prove that a particular manufacturers steel is inferior quality, or to determine some sort of ideal hardness for a saw plate? Just testing willy nilly, even with all sorts of chemical and metalurigal analysis is really not going to prove anything. In fact, it will just lead to more questions: where did that saw plate come from, did the owner do something to affect its temper, is that plate really indicative of the general set of saws produced or avaialble, etc, etc, etc. The real question should be what is the ideal range of hardness of a saw plate? Lets say you identify this, then what? Are we all to go purchase some exotic hardness tester in order to decide if a flea market purchase is worthwhile? I think this entire effort is fruitless.

[David Weaver]

The saws I'm sending are not "affected" by anything. They've not been overheated, nor are they overhard. I've filed them, and they file similar to any other disston. I believe they will prove that the measurements that have come before are valid for disston saws from their highest quality era (various hardnesses around mid 40s).

I personally have some saws that are softer or harder than the plates I'm sending (I have only had the one very defective straw temper saw - a disston, which made the garbage can a long time ago), but they are not what I'd call average saws from filing many. Other disstons from the same era have filed about the same.

If someone were to suggest that I can't tell the difference between a normal saw and a damaged saw and calls the data from these saws into question, I don't care.

[george wilson]

People keep asking the same question,Pat. He says he just wants to know for himself. So,he sees fit to take up a lot of space in this and his other forum.

Is this leading up to a claim of "I'm the saw hardness guru?" That would be a lower tier guru level to "I'm the saw sharpening guru". :)A little birdie told me it started as an effort to discredit some other custom saw makers. No idea myself what it is all about. That Aussie forum is so blasted complicated,I have no interest in trying to fathom its mysteries.

I say,if he wants to do it,do so and be done with it. Sez me. Then post 3 pages of charts and graphs that we may be enlightened. Or,just say it in one sentence like I already did"The old Disstons were from 40 to 45-48 RC."

[Tony Zaffuto]

People keep asking the same question,Pat. He says he just wants to know for himself. So,he sees fit to take up a lot of space in this and his other forum.

Is this leading up to a claim of "I'm the saw hardness guru?" That would be a lower tier guru level to "I'm the saw sharpening guru". :)A little birdie told me it started as an effort to discredit some other custom saw makers. No idea myself what it is all about. That Aussie forum is so blasted complicated,I have no interest in trying to fathom its mysteries.

I say,if he wants to do it,do so and be done with it. Sez me. Then post 3 pages of charts and graphs that we may be enlightened. Or,just say it in one sentence like I already did"The old Disstons were from 40 to 45-48 RC."

You've said it better than most of us George. It for the reason you've stated, that I have no interest in performing any testing at my plant, as I have yet to see how the data will be meaningful in any way, other than to determine hardness of the specific sample tested. With the modern saw makers, the suppliers of their saw plate material, will willingly supply certificates of conformity to the specification of material purchase, with hardness already tested.

[Rob Streeper]

The saws I'm sending are not "affected" by anything. They've not been overheated, nor are they overhard. I've filed them, and they file similar to any other disston. I believe they will prove that the measurements that have come before are valid for disston saws from their highest quality era (various hardnesses around mid 40s).

I personally have some saws that are softer or harder than the plates I'm sending (I have only had the one very defective straw temper saw - a disston, which made the garbage can a long time ago), but they are not what I'd call average saws from filing many. Other disstons from the same era have filed about the same.

If someone were to suggest that I can't tell the difference between a normal saw and a damaged saw and calls the data from these saws into question, I don't care.

Good, glad to hear that we will have good test subjects.

On the issue of personal experience or common knowledge, if you will permit me I will discuss a example that everyone is familiar with.

Consider cigarettes and tobacco. It has been common knowledge for a long time that people who smoke seem to have various health problems and that they die sooner on average than people who don't smoke.

From the days of my youth I remember when the first health warnings were being formally voiced by the Surgeon General. These warnings, and many others, divided the public. Some decided that their observations and the warnings of scientists, physicians and government officials had substance and they either didn't start smoking or they quit. Others rejected the warnings and continued smoking. I personally have heard many smokers say something along the lines of 'Old uncle Joe smoked 60 years and he was never sick a day in his life.'.

The physicians and statisticians and morticians however were working away in the background compiling mortality statistics on those who smoke and comparing those numbers to figures for people who didn't smoke. Over many decades of effort they have now come to a scientific consensus that smoking is associated with increased mortality and with increased incidence of a number of diseases.

Notice that I wrote 'associated with'. I wrote that because that is a fact. We have never been able to prove, in the scientific sense in which the word 'prove' is used, that smoking causes lung cancer for instance.

A proof in science and particularly medicine is a very rarely encountered level of evidence. Mostly we have a level of confidence that is called, again in the scientific sense of the word, a 'theory'.

A proof of the theory that smoking causes lung cancer would require us to conduct the following experiment. We would have to take a large number of people, likely many thousands, control every thing about their lives including diet, stress levels, and so on and divide them into test groups. These test groups would include controls who didn't smoke and groups that were made to smoke carefully measured amounts for defined times. These groups would need to include both men and women, there would be groups for all of the major races and ethnicities and we would have to start some groups young and some groups after the attainment of adulthood. We would then need to collect data for a normal human life span + 10% or so to account for the long lived such as 'uncle Joe'. Figure maybe a hundred years. In the meantime we would count the bodies as they piled up.
Notwithstanding all of the practical problems of conducting such a study we would also be behaving in a way that was totally unethical and cruel in the most extreme way possible.

Thus I think you can see that there is no way to prove scientifically that smoking causes cancer and more importantly there is no way to prove scientifically that a cancer in any particular person is due to their smoking or not. This is the main reason why the tobacco companies usually win when they are sued by sick smokers. The studies in animals, some of them primates that have physiological characteristics similar to ours, are the best empirical measure that we have that smoking causes disease.

I'm sure that you're asking yourself where I'm going with this so here it is.

Saw plate hardness is something that everybody 'knows' and can feel in filing saws. Nobody however has taken anything but a few measurements on the saws that are held to have the most ideal functional qualities from the golden age of Disston saws. Why do it? Because people are interested and moreover those of us who are bearing the expenses want to know. I feel that the results will give us better, albeit limited, insight into the hardness of these ideal era saws. This information will inform the historical analysis of Disston saws and supplement the extensive information on the net at places such as the Disstonian Institute plus it will serve to inform future saw makers of what at least a couple of Disston saws were like when all of the Disston saws have rusted away or become too valuable to test.

[george wilson]

You caught me before I could edit(clarify) my post to read "The saw tooth leveling guru",(filing teeth the LONG way) an even more esoteric guruship.:)

[Rob Streeper]

You caught me before I could edit my post to read "The saw tooth leveling guru",an even more esoteric guruship.:)

Talk about esoterica...

Here's an anecdote you may find amusing. In my saw making work I often use Argentine lignum vitae or Verawood. It is really hard and difficult to work with, not as bad as Gabon ebony but it definitely ain't walnut. I looking around the web for supplies I happened on a story about a guy who owns a brewry. He decided that he liked ALV and wanted to use it in his beer making business. He somehow found the wood and amazingly found a guy to make the vat for him. The thing was enormous, some thousands of gallons in capacity. Turns out the cooper and his son were the only people doing this kind of work in the country.

I bet the saw tooth leveling guru is a similar rarity.

I have another observation you may be interested in regarding tooth setting. If you wouldn't be bored by it I'll post it so that we can discuss it. Let me know.

[george wilson]

Vera wood is a CLOSE RELATIVE of the real lignum vitae. I don't know why such a heavy wood would be used for a saw handle. Plus,I always had trouble with it subsequently warping some and cracking. They sell it encased in wax,so it isn't dry enough lots of times.

No need to post how to set teeth for me. Others may want to see it,though.

Surprising they would use Vera Wood for a huge vat. I don't know what vera wood costs,but about 20 years ago,at a wood working show,I noticed a piece of lignum vitae about the size of a board foot for $125.00. They used to use it for propeller shaft bearings on large ships.

[Larry Frank]

I agree with some of the recent posts concerning the end result of this. Will all of this help me buy a better saw? When I decide to buy a saw I am more likely to read what George says about the one that cuts best. I have no idea if a hardness of 40 or 45 or 50 cuts better...I just want a sharp saw that cuts straight.

The company that I worked for was based on making decisions based a lot on return on investment. I want to know what the value of all this testing is...how it benefits me and others on the forum. Is it just testing because someone wants to know? Is someone using it as a platform to publish a paper?

In the end, the only thing I want to know is the relationship between hardness and saw performance. On second thought I will just buy what George recommends. I also want a saw that cuts straight in spite of my low level skill.

[Tony Zaffuto]

I agree with some of the recent posts concerning the end result of this. Will all of this help me buy a better saw? When I decide to buy a saw I am more likely to read what George says about the one that cuts best. I have no idea if a hardness of 40 or 45 or 50 cuts better...I just want a sharp saw that cuts straight.

The company that I worked for was based on making decisions based a lot on return on investment. I want to know what the value of all this testing is...how it benefits me and others on the forum. Is it just testing because someone wants to know? Is someone using it as a platform to publish a paper?

In the end, the only thing I want to know is the relationship between hardness and saw performance. On second thought I will just buy what George recommends. I also want a saw that cuts straight in spite of my low level skill.

Here's the kicker Larry: the test results will give no assurances that, for example, the Disston steel tested, that came from a #12, will be the same for the #12 you find at the local flea market. The range of variables that can give differences include the range of years of manufacturing of a specific saw model, the fact that all saws, of the specific model may not have been made from the same coil stock and so forth.

[Rob Streeper]

Here's a link to a story about the Argentine lignum vitae beer vat (10,000gal) I mentioned above. https://thedogsofbeer.wordpress.com/tag/palo-santo-wood/

[Dave Anderson NH]

While I have no person interest in saw hardness testing some people do. Like any thing else on this forum or anywhere else on the internet each individual can make their own choice as to whether or not to read, comment, or participate. I have seen plenty of extremely narrow and technical topics discussed here on the Neanderthal Forum, some to what I personally consider the point of exhaustion. I've seen others become a flash in the pan only to become resurrected and heavily discussed years later when someone struck a chord that animated one or more persons.

My point is simple, if you aren't interested don't denigrate someone who is. We all have our different interests within the focus of the Neander world and all of us lack interest in some of those areas. Whether one or more individuals think a topic is useful or not is immaterial. If there was absolutely no interest in a topic the initial poster (OP) would receive zero responses.

[Rob Streeper]

Here are the results of another experiment. I took a new piece of 1095 steel that will someday become a D-8 replica. I laid out a grid on it, hammered along the spine and a region starting about 1/2" above the teeth. I then hammered the saw along the lines on both sides and took Rockwell C scale measurements. Then I hammered the saw again. The data presented are:

Raw instrument readings in tables 1 and 2 for the blade after hammering once and twice respectively.

Corrected instrument readings after adjusting the data for the calibration curve in tables 3 and 4.

Measurements corrected for the effects of surface roughness caused by the finishing of the plate (added 2.18%) in tables 5 and 6.

The difference in hardness between hammering 1 and hammering 1 in table 7.

The difference between hammering 1 and the hardness of the 1095 stock material in table 8.

The difference between hammering 2 and the hardness of 1095 in table 9

Table 10 shows the lower limits of the hammered zones superimposed in table 9.

The green zones denote the areas that were hammered, the blue zones denote the areas adjacent to the hammered zones that had testing points within 3 or 4 mm of the edge of a hammered zone and the white zones were not hammered. Interestingly practically all zones increased in hardness whether they were hammered or not.
All of these measurements we acquired on the same day on the same steel, the only difference was the number of times hammered.

This is what I think may be happening:

http://www.shotpeener.com/library/pdf/2011009.pdf

http://en.wikipedia.org/wiki/Bauschinger_effect

http://dash.harvard.edu/bitstream/ha...pdf?sequence=1 (http://dash.harvard.edu/bitstream/handle/1/12164712/Davoudi_BauschingerEffect.pdf?sequence=1)

http://machinedesign.com/news/unders...s-autofrettage (http://machinedesign.com/news/understanding-basics-autofrettage)

http://www.ewp.rpi.edu/hartford/user...es/Hojjati.pdf (http://www.ewp.rpi.edu/hartford/users/papers/engr/ernesto/poworp/Project/4.%20Supporting_Material/References/Hojjati.pdf)

http://www.stsy.sjtu.edu.cn/uploadfi...%20tube%20.pdf (http://www.stsy.sjtu.edu.cn/uploadfile/pdf/Effect%20of%20Bauschinger%20effect%20and%20yield%2 0criterion%20on%20residual%20stress%20distribution %20of%20autofrettaged%20tube%20.pdf)


No pictures here because they won't upload and it's a big hassle for me to reduce them.

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Here's the data table in PDF format so you can have a closer look.

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[Pat Barry]

So, it seems that the steel is actually increasing in hardness as a function of hammering. Is that the message? That the testing supports the commonplace knowledge, that is a good thing. If there is more here than that you need to esplain it, there's just too much data and not enough information.

[Rob Streeper]

So, it seems that the steel is actually increasing in hardness as a function of hammering. Is that the message? That the testing supports the commonplace knowledge, that is a good thing. If there is more here than that you need to esplain it, there's just too much data and not enough information.

The steel is hardened, or appears to be hardened, in the areas adjacent to the hammering.

I made an interesting observation during the testing. When running tests on the hammered zones the needle on the tester stopped at a certain point under load (150kg). When the load was relieved the needle swung back up to indicate the hardness. In the non-hammered zones however the needle stopped at a somewhat lower reading than it did in hammered zones indicating that it penetrated the metal further than it did in the hammered zones and then when the load was released it came back to read harder than the hammered areas.

That's why I think the Bauschinger effect is in play here, there's a plastic compression zone (hammered) surrounded by an elastic zone (adjacent) under tension. So maybe, just maybe, Disston did start out with steel at ~52 C scale hardness and the hammering makes it appear that they are harder when in fact they are under Bauschinger / autofrettage tension. Bauschinger discovered this effect in 1881 (http://esaform2008.insa-lyon.fr/proceedings/MS04/p_Le_226.pdf). I wonder if one of Disston's sons read about it?

Nonetheless, I was able to produce hardness measurements approximating those I found on the Disston saws I tested under the handle, including apparent hardening in areas that were not hammered. Further those hardness values suggest the saws can't be file sharpened, but we all know that they can.

Too much data? https://www.youtube.com/watch?v=Q_UsmvtyxEI

[Tony Zaffuto]

What tester are you currently using and can you describe how the material is supported under the anvil?

[Rob Streeper]

What tester are you currently using and can you describe how the material is supported under the anvil? The plate was directly and fully supported by the anvil. I used the 150 mm anvil that came with the tester. The free end of the blade was rested on a support to prevent deviations. The tester is a beam-style analog Rockwell B and C tester. It was calibrated with a three point calibration curve with three replicate measurements at each point. The calibration curve showed an R2 value of 0.9965 indicating a linear response over the range of 27 to 62.

Here's the calibration data.304779
This is what I mean when I say 'linear'.

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[Rob Streeper]

I just noticed a calibration error, Excel likes to grab adjacent cells and it got ahold of a value I didn't specify. Corrected here.304781304782304783

[Stanley Covington]

Backsaws and handsaws are very different tools. It is ridiculously easy to make a decent backsaw. The flatness and straightness of the blade and shape, set and sharpness of the teeth are the critical points. But handsaws are not so forgiving, and are much more difficult to make. No one makes a handsaw nowadays that can hold a candle to the American handsaws pre-1950's. No one taper grinds, and no one hammer tensions. And the handles on Borg saws suck. The old Disston, Atkins, Jenkins, Bishop etc saws were made to satisfy men that used saws all day long, sharpened them themselves, and did not stint to pay several days wages for a good saw. I don't know how much you get paid, but that's a lot of money for a saw nowadays. The old saws are elegant, efficient, and still a bargain. Give them a try.

Stan

[Rob Streeper]

Backsaws and handsaws are very different tools. It is ridiculously easy to make a decent backsaw. The flatness and straightness of the blade and shape, set and sharpness of the teeth are the critical points. But handsaws are not so forgiving, and are much more difficult to make. No one makes a handsaw nowadays that can hold a candle to the American handsaws pre-1950's. No one taper grinds, and no one hammer tensions. And the handles on Borg saws suck. The old Disston, Atkins, Jenkins, Bishop etc saws were made to satisfy men that used saws all day long, sharpened them themselves, and did not stint to pay several days wages for a good saw. I don't know how much you get paid, but that's a lot of money for a saw nowadays. The old saws are elegant, efficient, and still a bargain. Give them a try.

Stan

Hi Stanley,

I agree with what you say about the classic handsaws. For me the first step in creating a handsaw is understanding the technical details of their manufacture. Sadly, much information seems to have been forgotten leaving me with the need to analyze the saws I can to try to reconstruct the techniques used.

Cheers,
Rob

[Rob Streeper]

I received the two saw blades from David. Here they are.

The leftmost blade is slightly bent concave as pictured, the right blade is slightly convex as pictured. The etched sides of both blades appear to be less rough than are the opposite sides.

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Here's the smaller blade with the testing grid.

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And here's the grid on the larger blade.

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Hardness measurements will be taken at the crossing point of each grid intersection with the following format long axis, short axis, Rockwell C scale hardness, Rc or HRC.

[Rob Streeper]

Okay, here's the data. These are first draft - I have not hand checked all of the input values. The corrections applied are as before, the first stage corrects for the offset of the instrument. The second stage adds about 2% to the values to compensate for roughness. These saws appear to be on the softer side, roughly Rc/HRC of 48-49 at the tooth line. Softer toward the spine. No real difference in hardness under the handle. More tomorrow.

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[Rob Streeper]

Here's the calibration data. I'm having to move the instrument to use it so I recalibrate before each use.

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[Rob Streeper]

Here are some more corrections. I've changed the designation D7 to #7 per David's information. I also bolded those values taken in the areas under the handles and done some formatting. I still need to double check all values against my notes.



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[Rob Streeper]

Interesting editorial.

http://bos.sagepub.com/content/71/1/33.full.pdf+html