I have three old compass and keyhole saws. One is a 19th century Disston, one an early 20th century Disston, and the third is a lesser saw. All are dull. I am going to sharpen them or have them sharpened — but HOW. Should they be rip or crosscut for best effect? How much set?
Joe
Replies
Hi Joe,
I file my two a little different from each other.
For thinner woods, one is sharpened more or less peg toothed using a regular saw file. Which is to say that the file is held so that the top side of the file is level with the tooth line. This makes the face of one tooth and the back of the tooth in front have equal rake (30 degrees each). This saw I also put over 30 degrees of fleam--I shoot for 4 degrees. Properly speaking, I shoould use a knife file so the teeth are properly tall as well (sort of as tal as Japanese teeth).
The other is file rather strongly cross cut. It has maybe 15 degrees rake and equal fleam angle. This makes for quicker cutting in thicker woods no matter the grain orientation.
Set depends on the shape of the blade itself. If it is a fairly long narrow blade and comes to a good point, less set. But enough that I can turn a reasonable tight curve. At least a tight enough curve that I would use the keyhole saw verses a bow saw wit a narrow blade.
I would say my peg toothed version has about 5 thou or so. I don't really know and it has been sharpened a coupe times since I last set it. But for thin stock, which is what I use it for, I can use the narrow tip to turn corners as the thin wood cuts easy enough without bending the blade unacceptably.
The other one also has a thicker blade aside from a slightly less long narrow blade. It has considerably more set as I use it on thicker wood and need to use the middle of the blade or near the tip gently in comparison to the other saw. I can measure it tomorrow if ya want.
Take care, Mike
Joe, send them to Mike and have him sharpen them. The you know they are right and should you ever want to sharpen them or others at a later date then you have them for reference...
Good idea.J
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