Saw Sharpening….and Fear.

As promised, the saw vise was completed a few weeks ago. It has made life easier. It works well as is, but a few minor modifications might make it better. A couple of strips of leather glued to the inside of the jaws might give them a little more grip, for example, but it is a vast improvement over the former arrangement, which was nothing. Once I had figured out the error of my ways, (read twice, assemble once, check), it went together painlessly. Quality screws made a difference. For the first time ever I bought and used some square drive screws from McFeely’s. What a revelation that was! They went in effortlessly and not a single cam out! Cheap screws are banished from my garage, er, shop forever.

Now it was time to do some saw sharpening. The old saws were brought down off their hanging hooks, the saw vise was attached to the bench, and the saw files were laid out to hand. The saw that needed sharpening the most was my 14″ Disston backsaw. It gets used as a carcase saw, mostly, for making crosscuts on smaller parts in conjunction with a bench hook. It shows up on the bench quite often during a project, so it needs to be at its best. I put it in the vise, clamped it down, reached for the appropriate file, and… slowly felt my confidence draining away. Filing a saw suddenly seemed like a daunting process. Ruining the saw was not an option. A dull saw is next to useless. This was the horns of a dilemma.

I’ve read several articles and watched a few videos on saw sharpening. It didn’t look too difficult. There is a technical/scientific aspect to sharpening a saw. Fleam, rake, slope, pitch, gullet depth, and set are all things to consider when sharpening.

Fleam is a fancy word for the bevel angle on the teeth of a saw. Rip teeth are filed at 90 degrees and are said to have no fleam.  Crosscut teeth are typically filed with a fleam angle between 15 and 20 degrees.

Rake is essentially how far the teeth angle forward (for Western style saws) into the wood. The more rake a saw has the more aggressive the cut. Too  much rake causes an ugly cut. Not enough and the cut takes a long time to complete.

Slope is the angle of the gullet of the teeth that the file makes when sharpening the saw. More slope can provide a sharper tooth and more room for saw dust, but it can cause tearing in the cut.

Pitch is also known as teeth per inch or points per inch. The more tpi, the finer the cut, but the slower the cut, too. Saws are often categorized based on tpi and whether they are crosscut or rip saws.

Gullet depth is important because deeper gullets reduce jamming by accommodating more sawdust. Gullet depth is relative to tpi, however.

Finally, set is when the teeth are offset alternately on the saw which causes the teeth to cut a kerf wider than the actual sawplate. This provides clearance for the sawplate and reduces the likelihood of the saw jamming in the cut.

Depending on which of these elements you tweak effects your saw’s performance. Some arrangements work better for softer woods, some are best for hardwoods. If you work with both, a compromise is generally the way to go unless you have a bunch of saws stockpiled and you can configure them for specific tasks.

Oh, and you can’t forget about consistency, either. Every source available says how important it is to use the same number of strokes on each tooth when filing the saw. The teeth need to be the same height.

So now all of this stuff is rattling around in my head and I can think of a million ways to screw up my old Disston backsaw. Paralysis by analysis is what it’s called. Over thinking. Fretting over making that first stroke with the file.

The file? It occurred to me, at this point, that I was being an idiot. Grade A prime cut blue ribbon idiot with gold oak leaf clusters surrounded by sparklers and sequins. I know how to use a file. Need to sharpen an axe? Give me a file and look out. Need a sharp machete? I’m your guy.  Looking at the saw in the vise brought back memories of tobacco knives (which look like a hatchet),  that were often made from saw blades; you often found them still with the saw teeth on them. I can have one of those razor sharp in under a minute. So what the heck am I worrying about?

So I picked up the file and I put it to the first tooth. The first stroke was light. Too light. The second stroke was heavier, but needed a bit more. The third stroke was about right. The tooth still looked like it needed work. Three more strokes and it looked….good. So I did the next tooth, alternating, of course, on a crosscut saw, and it looked good, too. Once that side was completed, the saw was turned around and the other teeth were sharpened. Oddly enough, none of those technical considerations like fleam, gullet depth, etc. seemed to matter. Sticking with the original configuration, or as close as possible, was the plan. When the saw first came into my possession it looked like it hadn’t been used much. The last time it was probably sharpened was just before it left the factory, so it didn’t need any set added to it.

Once the second side was done, it was time for the moment of truth; taking a scrap piece of poplar to the bench hook and testing the saw. It cut fast and straight. It did it again on the next cut, and again on the next cut into red oak. Still fast and straight. The only issue seemed to be that the cut wasn’t as clean as expected. For a first time saw sharpening, though, it wasn’t bad at all when compared with my new Lie-Nielsen and Veritas saws. After a couple of hours at the saw vise there wasn’t a dull saw in the shop.

I was  happy and upset at the same time. Happy that this had turned out to be less of a challenge than I thought, upset that I hadn’t tried this sooner. Again, over thinking had kept me from trying to do this for too long, but really the problem was not recognizing a skill I already had: filing. If you can operate a file, you can sharpen a saw. Try it.

Cheers,

The Bumbling Apprentice

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