A Saw Sharpening Question

[Richard Line]

I was refurbishing an Atkins saw that I had gotten from a friend. It wasn't in great shape, but it is a good practice saw. Everything has gone well with the refurbishing, but this question arose. How do you determine or measure the rake angle for a saw's teeth when its time for sharpening? Trying to measure it with a protractor doesn't seem reliable to me, too short a distance along the tooth for setting the protractor accurately. Is there a cool way to do this. This saw is an 8 point cross cut. To date all the saws I've worked on have had rake angles of 15 deg. This saw's rake angle was less than 15 deg. But what? I got through the sharpening by setting the file against the tooth and pressing down to align the file with the existing tooth. Of course this threw my 15 deg. rake gauge block off horizontal. Still, the saw ended up cutting well (I think I can improve the cut, but that is more practice for me).

[Chris Griggs]

What you did works fine, as long as the teeth are in decent shape. In general though, I don't bother to try to match an existing rake. For me its just easier to joint the teath down a tad and refile to the rake I want. Typically the teeth on the old saws I encounter need some reshaping anyway, so it's really not any extra work. Glad you got it working well though - a freshly filed saw is a wonderful thing.

[Marv Werner]

Hi Richard,

I do pretty much what Chris said. Establish your own rake and fleam angle on all your crosscut saws. Make them all the same. Makes it easier for future sharpenings. One thing I would add, always joint the teeth before filing. Having a flat, even a very small one on each tooth gives you reference to how much you are filing off each tooth and gives you a better chance of ending up with all the teeth even with each other and the same length. I file all my crosscut saw with a 15 degree rake and a 25 degree fleam angle. The exception is on a miter saw that is used in a miter box. On those I use less fleam and a little more rake.

[David Keller NC]

If you're interested in measuring the existing rake angle, one way to do it is to photograph the tooth line with a light behind the saw plate so that it's silhouetted. Then blow the picture up in a photo processing program, print a copy, and measure the angle off of the print.

[Jim Koepke]

There are many ways to do this and none of them are wrong as long as it works.

I throw my hat in Chris and Marv, I like what works for me as far as the rake angle and fleam angles are concerned.

I have been able to guesstimate the rake using a machinist angle checker.

This is the great thing about picking up all the inexpensive saws you can find.

Gives a lot of material to experiment with different rakes and tooth counts to find the ones that works best for your use.

jtk

[Richard Line]

H'mm, I'd say I've just received some very good and helpful advice. By the way, I did joint the saw before sharpening. As the only rake angle I had worked with before was 15 deg., that is on the 2 LV back saws I have (dovetail & carcass). I was curious about the rake angle used on panel saws made by the likes of Disston, Atkins, Bishop, etc. I've read plenty of discussions about the rake angle for rip saws, but don't remember seeing anything regarding cross-cut saws.

David, thanks for the idea on using a camera. I think I'll be doing that later today. If nothing else, it will help with the curiosity factor.