Filing a Great American Saw

A forum about crosscut saw filing

Filing a Great American Saw

Postby PATCsawyer » November 23rd, 2014, 2:11 pm

I picked up a Great American saw on Ebay recently and thought I’d try my luck filing it. Though I’ve filed a lot of peg and raker saws, the GA was new to me and there wasn’t much discussion on how to file it beyond the “Disston Handbook for Lumberman” and a few postings on this site.

My Ebay saw arrived dull, bent and rusty – typical of saws on the ‘bay. After a cleaning and straightening, I jointed it as I would any crosscut saw, taking the teeth down until I got a good flat spot on each one. I dropped the gullets ten full file strokes with a ¼”chainsaw file and then trued up the gullet edge with a crosscut saw file.

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This seemed to be an important first step since in order to cut clean, the outside of each gullet tooth has to be square to the face. I filed straight across the teeth to put a 90° strike across each tooth. I would use these striations as a guide for my next step, which was to point up the teeth. Starting with the inside edge of the outside teeth, I filed an angle approximating the one shown in the Disston guide. This was easy to do with a teardrop-shaped crosscut saw file, but would have been impossible with the mill bastards I usually use for saw filing. After getting a good angle on that inside tooth, I switched to the outside edge, taking GREAT PAINS to hold my file flat against the full length of the gullet. Note – THESE TEETH ARE TINY – compared to a typical crosscut saw and one can easily overfile with a single stroke. A few soft strokes established a good angle and I carefully filed this outside edge watching closely how my angled file strokes cut into the striations of my earlier squaring job. I filed until just the tip of the outside tooth edge was clean/smooth. I then returned to the inside angle and finished pointing up the tooth.

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I measured my included angle for these teeth and they were averaging 21°-23° along the spine of the tooth. My filing on the center tooth was closer to 30°, the difference seemed to be a function of how the saw was originally stamped out, which left the outside teeth smaller and steeper than the center tooth. It took great careful effort not to file “past the dot” and as I neared that point on each tooth, I stopped so that I could have a slight bit of metal to back hone before final pointing. With each tooth now finished, I hammer set each one to 0.012” using a coned hammer. The tiny teeth were too close together to safely whack with my usual Atkins hammer, and experiments with tack hammers were futile. The coned hammer just fit and I somehow managed not to crush any outboard teeth in the process. I also found it easier to set the teeth if I held my anvil perpendicular to the centerline of the teeth. Though not the “ideal” anvil placement, it worked for me, and the actual difference between a flat anvil and an angled anvil is probably lost in the weeds.

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Filed and set and off to the saw log. Though not as fast as my peg and raker saws, this little blade started easily and pulled smoothly in both directions. Of course there were no noodles but the chips poured out of the kerf, and no matter how hard I tried to catch an edge, I couldn’t do it -- it was a very forgiving saw to stroke. Note that my saw log was a dry, hard, oak. In softer, small diameter wood, I think this saw would fly.

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Re: Filing a Great American Saw

Postby bwilbur » December 5th, 2014, 4:56 pm

Thanks for sharing this. I just picked up a Great American tooth saw and there does not appear to be many shared experiences on the web for filing one of these. I was planning to use a tack hammer but I see that didn't work for you. Was it too light? Also, could you share a pic or details about the cone hammer?

Many thanks,
Brian
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Re: Filing a Great American Saw

Postby Dale Torma » May 30th, 2016, 2:38 pm

Here are some pics from a 1912 filing manual
image.jpg
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Re: Filing a Great American Saw

Postby Dale Torma » May 30th, 2016, 2:39 pm

The text mainly deals with circular and band saws, but has these pictures of filing a great American saw
image.jpg
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Re: Filing a Great American Saw

Postby Dale Torma » May 30th, 2016, 2:41 pm

Filing 2 teeth at a time
image.jpg
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Re: Filing a Great American Saw

Postby Dale Torma » May 30th, 2016, 2:45 pm

Filing the gullet, it seems one file does all the filing on this saw
image.jpg

I can't seem to attach more than 1 picture per post.
The little book does not have any pictures of a peg and raker saw and was written by a mechanical engineer
That's it for great American pics from this book.
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Re: Filing a Great American Saw

Postby PATCsawyer » May 30th, 2016, 4:47 pm

The pictures show all teeth to be of a similar size, unlike the squatty center tooth of my saw. I have another one of these in the wings -- an Atkins 334 -- and I will reprofile all the teeth as I file them.
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Re: Filing a Great American Saw

Postby Dale Torma » June 2nd, 2016, 9:11 am

I would think the center tooth would have to have the same rake angles, fore and aft, therefore would have to be twice the width at the base, of the outside "half teeth"
I think the drawings in the book may represent an artists interpretation, so your teeth, as they are, may be correct.
The two outside teeth I would say constitute " one tooth"
Just my 2cents

Maybe there is a factory instruction booklet for such saws somewhere.
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Re: Filing a Great American Saw

Postby Dale Torma » June 2nd, 2016, 9:17 am

The little booklet also shows a picture of an M tooth saw, and converting some of the teeth to clearing teeth, or rakers. I'll see if I can find the pics. There must be an issue with sawdust clearing with some of these saws. I was surprised the book did not have raker type saws included in the text.
The book is very disorganized, and some of the drawings are many pages away from the referring text.
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Re: Filing a Great American Saw

Postby PATCsawyer » June 2nd, 2016, 2:09 pm

I was going by the two sets of teeth on each end. My saw had obviously been refiled many times and in the jointing process, had been filed down further at the center than at the ends (typical of old saws). The end teeth were of equal width and had much longer teeth. Big difference is that the teeth on either side of the gullets were not filed like the picture, but we're only filed on one side (inside the V). Some had a retrograde filing that I cannot fix without a huge amount of jointing.
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