Positive rake on ripsaws

[Steve Voigt]

There is scant information on the web about this, so I thought it would be worth starting a thread. Has anybody tried using positive rake (meaning more aggressive than 0° rake) on a ripsaw? If so, how did you like it?
I recently picked up another ripsaw, and I was considering having it start with a couple degrees of negative rake at the toe, then transition to 5°-10° positive rake over the first 10 inches or so.
I did once find a pdf of an old saw filing manual, in which positive rake was highly praised, but I can't find it now. There are a few blog entries, including one on The Saw Blog, where Matt Cianci likens it to driving a Ferrari. Other than that, I haven't found much.

[Jim Koepke]

likens it to driving a Ferrari.

A Ferrari is fast. Some suggest wearing a kidney belt.

With positive rake a saw will likely rip through some woods faster. The other side of this is it will look like something tore through it in a hurry and be a bit tougher to handle even with padded gloves.

This is mostly opinion so remember:

278351

jtk

[Ron Bontz]

Just my 2 cents worth. I have a 26 x 5", 11ppi miter saw that was filed with a positive rake and very little set. I have no idea why it was filed that way. But the only thing it is good for is perhaps miter cutting 2 x 4s for building walls. It hangs on a wall of shame waiting to be refiled. Honestly, I do not see any real advantage to anything more than 0 degrees. You won't save that much time and it will just require more force to use. Unless, of course, you want more of a work out. :)

[David Weaver]

IF I was going to try to do something more aggressive than zero, it would have to be on a saw that had the handle fairly low with the hang straight ahead (i.e., very mild hang angle if any).

Otherwise, I've had problems with saws that have an aggressive hang even at zero rake - the saw bites and doesn't allow you to get a full stroke.

You can try it, though, and microbevel the teeth if they're too aggressive.

[Hilton Ralphs]

IF I was going to try to do something more aggressive than zero, it would have to be on a saw that had the handle fairly low with the hang straight ahead


Like this David?

278356

source: http://tinyurl.com/orl5gnw

[David Weaver]

Yes, the bottom handle is going to tolerate more aggressive rake (and maybe prefer it). Positive rake, I don't know, but a handle like the old english style prevents you from really leaning on the saw and having it bite in and put on the brakes.

[Kees Heiden]

I made a saw like that old English style with close to 0 rake. When I accidentally pull the saw back too far and the toe is inside the tenon cheeck I was working on, the saw tends to catch and stall. That is very inconvenient, so I plan to relax the rake a bit on the first two inch. (I have lots of plans like this...). I guess with positive rake it would be worse.

And I also had a miterbox with a positive rake sawblade. Useless. The saw catches and stalls all the time. Now it has a conventional cross cut tooth and is a delight to use.

[Steve Voigt]

Thanks very much, everyone. Ron, I'll take your advice.

Steve

[Jim Matthews]

If the teeth with more rake than zero degrees encounter something harder than the surrounding fibers, it would be suddenly difficult to drive forward.

I see this as a recipe for bent plates, blow out and sore elbows.
I was trained to file no more than vertical, and I'm generally at an "angle of attack" far less than 45 degrees to the surface.

I have a couple of two-man crosscut saws with teeth filed "less" than zero, but they're intended for green wood.
The "Champion" pattern has a splayed raker between the cutting teeth that acts as sweep to expel sawdust on both strokes.

That's only on saws so large they require a team to operate.