Fleam & rake for a miter saw

[Jim Koepke]

Aargh! I always get the drection of rake confused, negative or postive.

It confused me for a while. It is just the opposite of a bicycle's steering fork's rake. (used to be heavily into bicycles)

Now my way to remember is the slope of the tooth should "lean" back toward the handle.

My early filing of rip saws was to 9º rake. With the one that was just a saw plate and a shop made tote, the rake was set at 5º as was the fleam. The difference between it and my other saws is very evident.

For me, being willing and able to do my own saw filing has been educational by being able to actually feel the difference a few degrees can have.

jtk

[Ron Bontz]

I don't know - it's hard to see 5 degrees on the saw, of course, but 5 degrees over the length of a file is rather evident. Maybe exactly 5 degrees is tough, but it's relatively easy to see that it's not perpendicular. Back of the envelope, over six inches, I think 5 degrees puts end a half inch off of perpendicular.

Sorry. To be clear. ( My opinions only ) I measure my rake from 12 noon clock wise as you are looking at the teeth in the vise. ( up side down ) positive rake will look like hooks to me. I should have also stated( on my back saws ) 0* to 5* MAX. on the rip filings. Larger hand saws are a different critter. So it varies with the saw. It is correct as well that the increased weight of the plate adds to the aggressive nature of the saw, and some of the older vintage miter saws I found to have about 10* to 15* rake, give or take a skosh, and 30* fleam. ( Dedicated cross cut ) Basically there are four ways to make a saw seem to cut faster or smoother and start easier, given the same saw plate. 1) Lower the hang angle giving it more forward force, easier to start, (Lower your hand on your plane tote and push instead of up higher.) 2) Relax the rake, giving it less dig in, easier to start (more scraping , less slicing 3) Add fleam to slice more and smooth it out. ( skew your block plane a bit). 4) File it with more, smaller teeth. ( A 1/4" chisel removes less material and pushes easier than a 2" chisel) Now throw all those methods in together and see what shakes out. AHHH So in the end there are probably as many preferences as there are saw owners. http://i1179.photobucket.com/albums/...ps3b206caa.jpg Now that I have muddied the water even more. Enough said.

[Kees Heiden]

Muddled? No not at all.

How about the LV dovetail saw. 14 tpi and 14 degree rake! The hang angle isn't very high either. That makes an easy saw. Not especially fast probably.
At the other hand, my new dovetail saw, also 14 tpi and a rather low hangangle, but 4 degrees of rake, is quite easy too. But it has a tapered spine and a canted blade, which I certainly feel like helpfull to smooth out the cut and making it easier to start too. So add that as nr. 5.

[Ron Bontz]

Yeah. The canted plate just adds about a degree or so to the rake, making it a bit more aggressive. Not really noticeable, at least to me. It does however have an ascetic appeal and offers the illusion of cutting deeper on the front of the cut to avoid cutting too deep. I've said it before but the lee Valley saws are a great bang for the buck and a good saw. As you get better with them you can file them, or have them filed more aggressively to suite your needs. I edited the "Ramblings" a little to include the fact that each hang angle has a range of maximum functionality, depending on your preferences, etc. As far as the tapered spine. It lessens the toe weight slightly. On shorter saws 16" or shorter I found no substantial difference that can not be compensated for with 1* or 2* rake change. I use the tapered spines on my 20" Roubo saw, 1" down to .75". But while I can feel the difference in toe weight, the overall weight of the spine still seems centered on the plate for the most part. I have one more design to try yet. But another day.

[Hilton Ralphs]

Aargh! I always get the drection of rake confused, negative or postive.

You generally don't want a positive rake on a western saw. Unless of course you are literally hacking the poor thing to death.

[Ron Bontz]

You generally don't want a positive rake on a western saw. Unless of course you are literally hacking the poor thing to death.

Correct. Sometimes I look at the saw too much upside down, I think.

[Mike Holbrook]

That's the problem I have been having Ron, now I get it. All I have to do is stand on my head to think about rake and I should get it right, right?

I was just staring at the teeth on the Gramercy Sash saw under a magnifying light, maybe they do lean slightly more or less than 90 degrees to the front of the saw, but I don't think I can actually see it. The front (facing the front of the saw) of the teeth look 90 degrees to me. The hammer set makes them look like little waves breaking forwards, but it might be an "obstacle delusion". Since I have a hard time typing while "upside down" though, I may be getting it backwards.

The positive and negative thing seems to just confuse me more. I thought "positive' meant leaning more to the front of the saw tip, but wouldn't a forward lean make an acute or smaller angle to the front of the plate, which might be considered less or negative? I may have to learn to type standing on my head.

[Hilton Ralphs]

The positive and negative thing seems to just confuse me more. I thought "positive' meant leaning more to the front of the saw tip, but wouldn't a forward lean make an acute or smaller angle to the front of the plate, which might be considered less or negative?

Mike, you're making the mistake of looking at the angle of the gullet and not the tooth. Concentrate on the tooth and then you'll see that a positive rake angle is indeed larger than 90 degrees.

[Ron Bontz]

Finally back.. Not the best graphic in the world. But hopefully a little more clear. http://i1179.photobucket.com/albums/...psdc3eeaa3.jpg

[Kees Heiden]

Aha, yes that's what I thought too! But sometimes these things are named counter intuitive.

[Mike Holbrook]

There were two things that were throwing me off. One being which end of the saw plate is the toe and which has the handle, many pictures do not show a handle like Ron's does. I tend to look at saw teeth with the handle in my left hand and the tip in my right hand, the opposite direction from Joel's Sawtooth Design chart or Ron's chart above. The other was the realization that the angle is measured as degrees on either side of 90, 15+ vs 105, 15-, vs 75 (which just seems counterintuitive). Probably what Hilton is trying to point out? I think some people assume others know they mean negative rake simply calling negative rake "rake", causing some of the "less initiated" to misunderstand. I suppose if you look at the teeth from the point of view of a person sharpening the teeth the system makes some sense, but from the simpler view of just knowing what angle is being referenced from what other point not so straight forward IMHO.

Ron, thanks for illustrating things clearly.