Restoring a Saw

Jun 16 2014

I needed a new tenon saw. I got one from eBay for $35. It’s a Disston back saw. 12″ blade, 12 teeth per inch. As near as I can tell, from the mid-40’s. Disston was one of the premiere saw makers from the late 1800’s through the 40’s. After that, the quality declined. Unfortunately, that seems to be a pattern followed by most classic tool companies. Anyway, I’m pretty sure this is a quality one.

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Or at least, it was. The saw was a mess of contradictions. It was so rusted that it was almost a flat black across the entire blade. It was such a thick coating of decay that I almost thought someone had coated it with varnish or something. But the teeth were in great shape and the handle also looked good. The medallion stamped into etching on the side had almost totally worn away, indicating it had been used a lot, but not in a long time. My best guess is that someone owned it and used it and took very good care of it. And then, maybe that person retired or died, or sold it to someone else and it wound up sitting unused for decades. It was not abused, just abandoned. Then again, maybe it was just never used and the faded medallion etching was just due to it rusting away. (Realized after typing this that the “medallion” is the fancy round screw head on he handle, not the etching on the blade itself.)

I started by removing the handle and spraying some WD-40 on it, rubbing it in with some steel wool and letting it sit for a half hour. Scrubbed it a bit, sprayed some more, let it sit a while longer. But that wasn’t touching it in the least.

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So, I got out the sandpaper. First some 120 grit, then 320. Not ideal for preservation, but the quickest way to get it into a usable state.

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This generated a huge pile of rust powder, but in the end, it looked half decent. The goal wasn’t to get it shiny new, just workable. Put a light coat of oil on it to prevent further rust and later on I might give it a coat of wax for the same purpose, and to help it cut smoother.

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As I said, the handle was in decent condition. It could have used some sanding and a coat of oil or varnish, but that would just be cosmetic. Just looking to get this thing functional at this point. I might go back and work on the handle some more later, but this is good for now.

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Next up, sharpening. I put the saw in my Disston saw vise and sharpened all the teeth for a rip cut, with passive rake at the toe, moving towards a more aggressive rake a couple inches in.

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Finally, used the saw set to … set the saw. This involves pushing every other tooth in the opposite direction. Actually, I think the set was half decent, but I ran through it just to make sure they were all uniform.

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At this point, time to test it out. It cut fairly well on a rip, wouldn’t really cut at all cross grain. A 12 tpi rip saw with a progressive rake should crosscut half decently. So I went back in and gave it another round of sharpening. I figure the teeth may have looked good, but probably had as much rust on them as the rest of the blade. A single filing probably mostly just got through the rust. The second filing seems to have improved things a lot. I also removed some of the set with a couple of hammers. Now it rips perfectly and crosscuts decently.

Not bad for $35 and 2-3 hours of a Saturday afternoon. I now have a high quality vintage saw that will last me the rest of my life.

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