alternate filings

[bridger berdel]

I'm not a collector, I swear. I just can't pass up an old tool for ridiculously small money, especially if it looks like it will clean up OK. Or if it looks like it might have useful parts. Or if it just looks cool. And I like saws. And sharpening. And gadgets. Stuff with cool old hardware and moving parts. So as a result I have a drawer full of saw sharpening stuff, sets and jointers and filing guides. A few of them are complete and working, and when that happens they tend to move on out and become a part of some working kit. A couple of weeks back I was churning the parts to see if any complete tools might emerge when I realized that I had two filing guides of similar design, one missing the top half, the other missing the bottom half. Or maybe that's what they are, so I stuck them together. They aren't an exact match but I think the resulting gadget would actually work, though it will require a saw vise to be made that can hold a full length saw in one set and has a flat top lip. I think I can do that. And a couple of days ago I found a pretty nice disston backsaw for a couple dollars at a thrift store. It needed a pretty serious de-rusting and the wood was beyond repair, but I like making handles....

So now im thinking about tooth patterns for a fine tooth backsaw. I have this same saw in rip and crosscut, so I can play a bit with this one. I'm wondering what it would be like to have this saw filed 0° rake, 0° fleam and about 20° sloped gullets. I'm guessing it would be a lot like an aggressive crosscut tooth pattern, but never having had such a beast in my hands I can do no better than guess at this point.

Anyone here gone down the sloped gullet rabbit hole and can comment?

[David Weaver]

I've filed a crosscut saw like that in the past. It's still a rip saw. I can't remember if I did it exactly like that, but I ended up with a grabby saw - the zero rake means the sloped gullet does not impart any fleam on the cut, and the fact is you still have a ton of little zero rake points at...well...zero rake. They're like a brake.

In day to day sawing, I can't see any advantage to sloped gullets. the bigger issue with filing saws is learning to file a crosscut saw so that it's in a sweet spot with wood. If it's too aggressive, it leaves a coarse cut. if it's too fine, it rasps and you have to bear down on it. It's my opinion that they are more of a marketing display, something for the various saw filers to tout.

The smaller the teeth, the less practical need there is for much fleam to score the cut. I tend to err on the side of a more aggressive cut so as not to have a rasping set of saw teeth, and was never really impressed with sloped gullets vs. just getting the aspects of a flat filing correct.

that said, if you sharpen a saw better when you've got the saw tilted, then do it by all means. It does give you the ability to cut with the file facing a favorable way on the saw plate (for example, lessening screeching on saws with big teeth....however, you can literally do the same if you have major corrective work to do by just leaning the handle of the saw down about five degrees until the final passes, and you will not get screeching).

[Tom M King]

I like sloped gullets on a handsaw I use for cutting Cypress siding, but Cypress is a lot softer, and different than the typical wood people use for making furniture. I knew a couple of old guys, now gone, that put slope on every saw they filed, but it was just because of the angle they held the file. I don't think you will be completely happy with a saw filed with that geometry. Sharp will work with weird geometry, better than dull with the ideal geometry in any cut, in any wood. Hand saws were all people had to work with for a lot longer than people have had power tools. They found out what works, and it would be hard to come up with a geometry different than what they used, that would work better, or at least be useable longer.