Folded or machined brass backs?

[Bob Jones 5443]

For a Western dovetail saw, are there important differences between folding the brass back and machining the back with a groove for the blade? Our fellow member Pete Taran writes, "Don't believe the hype surrounding the 'virtues' of the folded brass back." I'm wondering if the folding helps make a more positive connection than a machined groove for holding the blade solidly. What do you all say?

[ken hatch]

For a Western dovetail saw, are there important differences between folding the brass back and machining the back with a groove for the blade? Our fellow member Peter Taran writes, "Don't believe the hype surrounding the 'virtues' of the folded brass back." I'm wondering if the folding helps make a more positive connection than a machined groove for holding the blade solidly. What do you all say?


Bob,

The folded is easier to remove and replace the saw plate. Sometimes a saw plate needs to be straighten or re-tension and that to my knowledge is also easier with a folded back. Best I can tell for normal saw operations there ain't no difference. Of course as always YMMV.

ken

ken

[Tom M King]

Saw smoothly, and it won't matter, even if it does.

[Jim Koepke]

IMO, the filing of the teeth is more important than the way the back is made.

jtk

[David Bassett]

IMO, the filing of the teeth is more important than the way the back is made.

jtk

... and hang angle, handle size, weight, balance, etc.

I'd have to guess, *ALL* *ELSE* *EQUAL*, the perfectly made folded back might be slightly better. But I don't really know. However, I'm pretty sure everything else is never equal and since everyone's preference (and skill level) is different that's probably a good thing.

[Pete Taran]

Here is the thing that might shed some light on why I think milled backs are better. Back in the old days, before Independence Tool, I filed saws as a hobby. Virtually every back saw that came in had the back jacked up. The reason is simple, it got dropped, the back hits first, and gets driven on to the blade which lifts it out of the mortise in the handle. Harvey Peace recognized this and patented a feature to put a bolt though the spine, back and blade to prevent this from happening. The problem is real.

So, when I set about designing a modern dovetail saw, I devised the milled, slotted solid brass back to prevent this. The slot is .375" deep and the blade is seated completely and glued with industrial epoxy. You can drop that saw all day every day and the blade will remain straight. It can't move. Folks that make saws with folded backs extol the virtues of taking the blade out and all that jazz. If the blade never moves, it never needs to be removed. Kind of like a car maker extolling the virtue of a car with an easily removable windshield because they don't supply seat belts. Does not make sense to me.

Finally, I occasionally get an original IT saw in for sharpening. Every *single* one has the blade as straight today as when I made it back in the 90s. None are newer than 22 years at this point. That is a pretty good track record if you ask me.

The reality is it is a lot harder to mill at .020 thick slot in solid bar stock than it is to fold brass to make an old school back.

Hope this provides some insight on why the milled back was created to start with.

[Tom M King]

Even if you needed to take the blade out of one that was epoxied in, it wouldn't be that hard. All you have to do is heat it, much like pulling the heads off golf clubs. Golf club epoxy is engineered to break down about 100 degrees before the epoxy that laid up the shaft. It shouldn't be that critical for a back saw with whatever type of epoxy is used.

I like the epoxy idea, but I don't think I've ever dropped any kind of hand saw, and especially not a backsaw. I've taken good care of my toys since I was a little boy though.

[Ron Bontz]

Interesting. I wrote about this some time back with regards to folded backs vs slotted backs vs moulded etc.. Pros and cons. So take it for what it's worth. Just some thoughts. The Richardson Bros. saw I copied some years back had the pinned back Pete mentioned but had also cracked the handle because of the plate and back shifting when dropped. I was playing around with compressing my saw spines at the time as well as experimenting with folded backs. I decided to pin the compressed slotted spine at both ends instead of just one end. The plate was tight all the way down the spine and could not go anywhere. The down side was that the stainless set screw I used was visible at the toe end, but otherwise it worked very well. Another down side, of course, was the amount of extra time drilling and tapping those set screws in. The epoxy is quicker and works. A saw plate that can shift in the spine is NOT an advantage. It is an inherent flaw in that type of saw back. If some one says they "Like to be able to re tension their saw plate" ask them why they have to do that in the first place. There is no real tension on that saw plate because there is no real mechanical means to prevent it from moving other than the friction force exerted by the minimal compression/ contact area. In other words, as soon as you start cutting with a folded back you have basically lost any real tension and placed compression on the plate heel. The plate is placed under compression toe to heel because it is pinned only at the heel. The compression force of the folded back will keep it straight, providing it is a strong enough "pinch" but there is no real tension at that point. Any mechanical engineer should be able to confirm this.
However, by pinning the plate at the toe end and creating that mechanical connection, once the saw cut passes that pinned point there becomes a tension force on the saw plate due to the forward stroke, resistance of the teeth into the wood, etc., keeping the plate straight by balancing the compression and tension forces. If the sum of the forces does not equal zero, something is going to give. Think of it as a Japanese saw in reverse. :) On any given saw there is a compression force and a tension force acting at the same time. I have this sketched out some where but at the moment I have no clue where on this neuron burning machine it is hiding. There are other pros and cons to these backs, but ultimately to time consuming to discuss here. Want to know more? Call or email me. My opinions and facts are free. My saws are not. :D I will leave this with a picture of that Richardson Brothers saw I made. I never really liked the handle , but it was a copy of the original.
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[Tom M King]

In using different adhesives for building golf clubs, I ran across one I really like. If it's strong enough to hold a golf driver head onto a .335 inch shaft, while hitting a golf ball at 120 mph, it should be plenty strong enough for most things.

As far as I know, it's only available in the little duo-tubes, so best used with a dispensing gun, and mixing nozzles, which has the benefit of allowing you to run a tiny bead right where you want it. It's 3M dp810. It comes in several colors, and clear. The main thing I like about it, is when you heat it to pull a head, it bubbles up, and turns into a crackly, bubbly mass that is real easy to clean off. It also sets up pretty quickly.

Some tour vans use it because of quick set, and ease of cleaning. The pros can test different shafts with a pretty quick turnaround.

Downside is that it's not cheap, but it doesn't take much to glue on a golf club head, and I wouldn't think it would take much in the slot of a backsaw back either. The mixing nozzles are, of course, disposable after one use, but you could do several in one session.

Best place to buy a gun, and nozzles is Golfworks. dp 810 is easily found online. It holds metal iron heads onto metal shafts just fine.

[ken hatch]

Ron, Pete,

Thanks. You both said it much clearer than my fumbling reply. I'm old enough to remember the commercials for Ford trucks where they tried to made having old technology an advantage. Remember the ads for "I-Beam front suspension" just like the "Big Trucks" use that ran for years. Then because they sold the snake-oil so long for years they had to use a cobbled together "I-beam" arm for the trucks. I still will not buy a Ford truck because of the dishonesty of those ads and the company response to them.

BTW, I still not sure if Ford trucks have a modern front suspension or not.

ken

[Warren Mickley]

I have used folded backs for my entire career. We woodworkers have been using folded backs for centuries. It is somewhat humorous to read that someone has now decided that they do not work very well.

[Pete Taran]

Warren,

Interesting perspective. People also used to use beasts of burden for transport instead of automobiles. Some peeled the scabs off people afflicted with deadly disease and ate them to protect themselves instead of getting a vaccine. Still others used land lines to make phone calls instead of using cell phones. These things are all referred to as advancements in technology. It's humorous to me that someone would not recognize that fact.

[Warren Mickley]

If making slotted backs saves labor or enables someone to make saws with less outlay for machinery, I am all for it. If people make spurious claims about how folded back saws do not hold up, I feel the responsibility to say something. I think we would have had slotted saws in the 19th century if there were real problems with folded backs.

[Pete Taran]

Warren,

The claims are real, not spurious. If you look through the letters patent at the inventions to keep saw blades straight in their backs, you would realize that there were many approaches to combating this problem. The most common was the screw through the back like the picture of the Richardson saw shown. At least 3 makers used this approach, Richardson, Peace and Boynton. It helped some but still didn't prevent the back at the toe of the saw being driven down on the blade.

As to having slotted slots in the 19th century, it wasn't possible. Slitting saws and milling machines were not advanced enough to perform this function, and even if they were, no adhesive known could cement the blade into the back. Additionally, the thickness of the saw blades varied slightly. Modern steel is very uniform. There were many factors that relegated this to a 20th Century fix.

There are many, many people that have a Lie Nielsen solid brass slitted saw back. Can anyone on the list point to any issues with their saw plate being kinked, misaligned or otherwise less than perfect? Additionally, Lee Valley uses a similar approach, but instead of metal they form the back around the blade through plastic injection. Same idea, different method. All fix the same problem, the propensity of the saw blade to move around in it's back due to rough handling or abuse.

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[Jim Koepke]

I have used folded backs for my entire career. We woodworkers have been using folded backs for centuries. It is somewhat humorous to read that someone has now decided that they do not work very well.


If making slotted backs saves labor or enables someone to make saws with less outlay for machinery, I am all for it. If people make spurious claims about how folded back saws do not hold up, I feel the responsibility to say something. I think we would have had slotted saws in the 19th century if there were real problems with folded backs.

Warren, Please help me here, after going through this thread once again the post claiming folded back saws do not work well seems to be eluding me. The comment closest to stating a reason why slotted backs may be better is from Pete Taran:


Here is the thing that might shed some light on why I think milled backs are better. Back in the old days, before Independence Tool, I filed saws as a hobby. Virtually every back saw that came in had the back jacked up. The reason is simple, it got dropped, the back hits first, and gets driven on to the blade which lifts it out of the mortise in the handle. Harvey Peace recognized this and patented a feature to put a bolt though the spine, back and blade to prevent this from happening. The problem is real.

He is stating an opinion, "why I think milled backs are better," based on his experience and a patent by a 19th century saw maker.

As far as manufacturers of saws goes there are many reasons why saw backs remained folded instead of slotted. One would be the cost to change. Another would be the old, "this iis the way we have always done this and we aren't going to change now" nature of humans. In my experience some very well paid engineers felt making a change is tantamount to admitting something was wrong with their previous work. Some could not except the concept of a new method or discovery. Many of those companies with such engineers were my employers in the past. Most of them are no longer in business.

The "spurious claims about how folded back saws do not hold up" have also eluded me. Again Pete mentioned the saw blade may become shifted if a folded back saw is dropped, misused or in some cases being thrown across the room. Many tools from centuries past do not hold up to such unfortunate events.

My only brass backed saws are made with slotted backs. All of my folded back saws have steel backs. One of my brass backed saws was a kit. The fit of the blade was made tighter by applying pressure to the area on the sides of the back over the slot before inserting the blade. It holds the blade with spring pressure similar to a folded back. Care is taken not to drop my tools or allow them to be knocked off of my bench. My tools are not thrown in moments of frustration.

The first four replies to the OP were pretty much saying the type of back isn't a big game changer:

(Minor editing)


The folded is easier to remove and replace the saw plate. Sometimes a saw plate needs to be straighten or re-tension and that to my knowledge is also easier with a folded back. Best I can tell for normal saw operations there ain't no difference. Of course as always YMMV.

ken


Saw smoothly, and it won't matter, even if it does.


IMO, the filing of the teeth is more important than the way the back is made.

jtk


... and hang angle, handle size, weight, balance, etc.

I'd have to guess, *ALL* *ELSE* *EQUAL*, the perfectly made folded back might be slightly better. But I don't really know. However, I'm pretty sure everything else is never equal and since everyone's preference (and skill level) is different that's probably a good thing.

My use of old tools isn't based so much on the aesthetics as it is on the lower cost of acquisition when compared to modern tools. In some cases collector fever have driven up the price on particular vintage tools. In that case my choice is to purchase a tool of current manufacture if it is truly needed or desired.

jtk

[Warren Mickley]

One guy says the claims were real and another says there were no claims.

[Jim Koepke]

One guy says the claims were real and another says there were no claims.

One guy is making claims* to the folded backs allowing slippage of the blade when a say falls off of a bench or meets with some other rough handling. Since Pete used the words 'why he thinks' and explained how this became what he thinks, it led me to feel it is more his personal opinion based on experience, something that may be changed if influenced by new information or experience.

Unless a claim of slotted back saws somehow cuting better slipped by me, the only claims Pete made were in his post of 7:58am PDT.

My last post on this was being composed when Pete posted:


The claims are real, not spurious… (edited)

As to having slotted slots in the 19th century, it wasn't possible. Slitting saws and milling machines were not advanced enough to perform this function, and even if they were, no adhesive known could cement the blade into the back. Additionally, the thickness of the saw blades varied slightly. Modern steel is very uniform. There were many factors that relegated this to a 20th Century fix.

There are many, many people that have a Lie Nielsen solid brass slitted saw back. Can anyone on the list point to any issues with their saw plate being kinked, misaligned or otherwise less than perfect? Additionally, Lee Valley uses a similar approach, but instead of metal they form the back around the blade through plastic injection. Same idea, different method. All fix the same problem, the propensity of the saw blade to move around in it's back due to rough handling or abuse.

It wasn't viewed until after my was post was sent.

On the point of a slotted brass back machined to match a blade being held in by modern adhesives being better at keeping a saw blade from slipping… Pete has seems to have a good point.

If anyone tries to claim one lasts longer than the other they have a problem with all the saws that have been around longer than any of the modern saws.

Instead of tilting at windmills why not tell us all what advantages you may see to a folded back?

Let me start, if one wants they could easily change blades for different tooth counts or filing. My Bishop #10 is one example of a maker who saw this possibility:

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For someone who has to carry tools to the job, it might be nice to have 3 or 4 different blades the user could switch out as needed.

jtk

[Eric Rathhaus]

Or it might be more common for tools carried to jobs to receive rougher treatment?

[Jim Koepke]

Or it might be more common for tools carried to jobs to receive rougher treatment?

That is often the reason why my best tools might stay in the shop and my second tier tools are taken on remote jobs.

jtk

[Ron Bontz]

I am not sure if it is allowed, But I found that original writing I had. It took a while. :(
But here is a link to it if it is allowed. Hopefully it makes clear my points. Certainly no offense meant to anyone. Best wishes.
https://www.bontzsawworks.net/home/random-thoughts/


(https://www.bontzsawworks.net/home/random-thoughts/)

[ken hatch]

I am not sure if it is allowed, But I found that original writing I had. It took a while. :(
But here is a link to it if it is allowed. Hopefully it makes clear my points. Certainly no offense meant to anyone. Best wishes.
https://www.bontzsawworks.net/home/random-thoughts/


(https://www.bontzsawworks.net/home/random-thoughts/)

Thanks Ron, I had not read that post before.

ken

[Phil Mueller]

Great write up, Ron. Thank you.