A saw handle isn't exactly Rome.
Member
A saw handle isn't exactly Rome.
Contributor
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.
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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.
Member
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."
Last edited by george wilson; 01-16-2015 at 12:41 PM.
Member
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.Originally Posted by 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".
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."
If the thunder don't get you, the lightning will.
Member
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.
Last edited by Rob Streeper; 01-16-2015 at 1:46 PM.
Member
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.
Last edited by george wilson; 01-16-2015 at 1:46 PM.
Member
Talk about esoterica...You caught me before I could edit my post to read "The saw tooth leveling guru",an even more esoteric guruship.
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.
Last edited by Rob Streeper; 01-16-2015 at 1:42 PM.
Member
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.
Last edited by Bruce Page; 01-16-2015 at 3:50 PM.
Contributor
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.
Member
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.
If the thunder don't get you, the lightning will.
Member
Here's a link to a story about the Argentine lignum vitae beer vat (10,000gal) I mentioned above. https://thedogsofbeer.wordpress.com/...lo-santo-wood/
Moderator
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.
Dave Anderson
Chester, NH
Member
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://machinedesign.com/news/unders...s-autofrettage
http://www.ewp.rpi.edu/hartford/user...es/Hojjati.pdf
http://www.stsy.sjtu.edu.cn/uploadfi...%20tube%20.pdf
No pictures here because they won't upload and it's a big hassle for me to reduce them.
Here's the data table in PDF format so you can have a closer look.
D-8 Hammering Experiment hardness measurements 011915a.pdf
Contributor
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.
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