Crosscut Hand Saw Rehab

[Derek Cohen]

Hi Phil - thanks for the tip here. I actually did try a paper pattern first but found it difficult to keep the file right on the line. And, yes, there is one small area of pitting on the tooth line but it's not even near where the teeth broke off...strange, right??

Tate, I imagine that many starting down the sharpening-from-scratch road believe that the teeth need to conform exactly to the lines on the paper, and if they do not then all the teeth will end up misaligned.

Just get the teeth as close as you can (to the line on the paper), and do not worry about the spacing at this stage. It is early days. As you continue to file, you can (and will) move the position of the tooth by taking a little more off the front or the back of a tooth. There is quite a bit of filing to do when you begin with a toothless or near-toothless plate, so there is quite a bit of time to move the teeth into the desired spacing. We are talking under a mm here much of the time, so the tooth count, per se, does not itself change.

This method takes more time, which means more patience for the amateur (like myself). But you will get there. No fancy equipment needed, unless you are making many saw plates regularly.

Regards from Perth

Derek

[Tom M King]

I have no idea how many hundreds of times I've sharpened a handsaw, but know exactly the number of times I've even thought about completely retoothing one-0.

[Derek Cohen]

Mostly agree Tom. The exceptions are when significantly changing the rake of teeth, or when rehabbing old saws. Once set up, I tend to keep this going.

Regards from Perth

Derek

[Stewie Simpson]

To make a change to the front rake angle of the saw teeth is not a legitimate reason on why you would bother to re-tooth a handsaw. To suggest otherwise is totally misleading.

Stewie;

[Phil Mueller]

Stewie, I have a miter saw with way too much rake...like 20 degrees... and would like to decrease it without re-toothing (which is what I thought I would need to do). To decrease rake, would I just need to heavily joint first (maybe 1/3-1/2 the tooth height), and then refile with the new rake angle?

[Derek Cohen]

To make a change to the front rake angle of the saw teeth is not a legitimate reason on why you would bother to re-tooth a handsaw. To suggest otherwise is totally misleading.

Stewie;

Stewie, and others, how would you deal with a plate which has 14 degree rake (rip), and you wish to change it to 5 degrees of rake? Would you just file the front of the teeth, or would you file them down (not altogether but at least half way) and retooth?

Regards from Perth

Derek

[brian zawatsky]

To make a change to the front rake angle of the saw teeth is not a legitimate reason on why you would bother to re-tooth a handsaw. To suggest otherwise is totally misleading.

Stewie;

Care to explain this? 1 or 2 degrees, ok. But any more than that and a very aggressive jointing is needed (like down to nubs) or you will change the saw’s pitch.

[Pete Taran]

All,

Here is the explanation. I think there is a lot of confusion about rake and saw filing angles and how they work. The most important thing to understand is that the file is 60 degrees as it's an equilateral triangle, so the only thing any filer need be concerned with is how the face of the file that defines the rake angle is held.

Check out the diagram I sketched up which is attached. There is one toothline superimposed over another. One has my preferred rip rake of 4 degrees, the other the traditional crosscut rake of 15 degrees. If you study it closely, you will see a few things. First, the heights of the teeth are different and are dependent on the rake angle. The highest tooth possible is a 30 degree peg tooth. The shortest tooth possible is the 90 degree or zero degree rake tooth.

It is not necessary to remove half of the teeth to change rakes. I do this conversion all the time and as Stewart suggests, would be a waste of saw steel and blade height to recut teeth for a rake angle change.

In the diagram shown, you need only be mindful of what metal you need to remove to get the effect you are after. I point that out in the diagram. If you stop when you hit the tip of the tooth, you will notice there is a small area that is not fully formed because of the previous tooth angle. You can continue to file deeper to completely remove all traces of the old tooth, or not worry about it since it's on the back side of the tooth and doesn't impact the cut in any way. I typically leave it, especially considering that more space for saw dust is better than less. Additionally, the most important real estate on a saw is how much width is left in the blade. Over jointing and filing just uses your saw up faster.

Hope this helps.

FilingMysteriesRevealed.jpg

[brian zawatsky]

Thanks Pete, that makes a lot of sense. Don’t know why I never looked at it that way. Every time I made a major rake angle adjustment I jointed the saw way back (~1/2 tooth height) thinking it was necessary to keep the same tooth pitch. Also the aesthetics of the hump in the back of the saw tooth bother the heck out of me, probably as a function of my OCD haha!

[Phil Mueller]

Thank you Pete. The diagram helps a lot to understand this. Your tag says it all: Filingmysteriesrevealed.

[Tate Harmann]

Well, I went to work on this saw just now and I think it turned out OK. Not perfect - but it cuts wood and that's what counts, right? Thanks to everyone for their help on this. Would I want to do this every day? No. Would I do it again to restore a saw? Of course I would!

The new file cut like butter and I used some different wood pieces to serve as the jaws this time (these are some walnut pieces I normally use as winding sticks):

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Here's how she looked after a few passes:
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The right side of this pic are the 2 inches of "starter" teeth gradually forming the aggressive teeth on the rest of the saw:
0203191424a.jpg

And all finished with some test cuts:
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[Tate Harmann]

A test rip and cross cut in red oak:
0203191436a.jpg0203191438.jpg

When I saw setting the saw I noticed some small flat spots still on the teeth so I may make another pass on it. I may also relax the rake angle on these teeth as I think that zero degrees is way to aggressive haha.

Again, not perfect, but cuts great!

[Tom M King]

If it's just a couple of little flat spots, they can wait until the next time the saw needs sharpening, and it will make a difference that approaches zero.

[Derek Cohen]

Thanks for the explanation, Pete.

I suggested as extreme an example as I could think of. Going the other way - relaxing the rake - is pretty straightforward. The usual cases where I have retoothed have been rehabs of vintage backsaws. Generally the teeth are a mess - wildly irregular or too large and too few.

Regards from Perth

Derek

[Tate Harmann]

Thanks for the explanation, Pete.

I suggested as extreme an example as I could think of. Going the other way - relaxing the rake - is pretty straightforward. The usual cases where I have retoothed have been rehabs of vintage backsaws. Generally the teeth are a mess - wildly irregular or too large and too few.

Regards from Perth

Derek

Hi Derek,
The reason I retoothed this one was on account of this was how it looked:

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