Sharpening a Rip Saw

[Tom Winship]

I sharpened a 4 tpi saw for a neighbor gratis. I filed the teeth straight across with no fleam and on the same tooth angle as received (about 8 degrees).

The saw teeth are sharp, however the saw doesn't cut like I think it should. Any suggestions?

[David Weaver]

It may be that 8 degrees is too much rake. I have my biggest toothed saws around 5, and even that feels pretty easy.

Look across the saw teeth tips in raking light and make sure you don't see any glint of light from a flat on the teeth tips.

I don't know that I've used a rip saw with 8 degrees of rake, so I can't think how much of an effect it would have, though I know at 15 (on crosscut saws after I reshape teeth before giving them fleam), i sure wouldn't want to have to rip a board. I tried one once just to see how it would work, and it didn't want to rip anything.

[Tom Winship]

Thanks, David. I wondered about that. Also, how common are 4 tpi saws? I assumed this was a rip saw, hopefully correctly so.
Tom

[Marv Werner]

Tom,

I've filed lots of rip saws with 8* rake with larger teeth like what you filed. However, I prefer 4 or 5* rake on that kind of saw.

8* degree rake is when you want a saw that cuts easy and slower. And of course it depends a lot on what kind of wood you are sawing and how thick it is.

Is the tooth profile 4 TPI or 4PPI? If it's 4PPI, it will have 3 TPI. This tooth profile is not as common as 5 or 5-1/2 PPI. (points per inch) as is usually stamped just below the handle.

[Jim Koepke]

The saw teeth are sharp, however the saw doesn't cut like I think it should. Any suggestions?

Is it not tearing through wood or is it wondering. I use 8° on my rip saws, but do not have one with that big of teeth.

Just to make sure, the rake should have the teeth pointing forward when viewed from the line of the teeth points and not back. If they are pointing back, the teeth will be likely to roll over the wood.

jtk

[David Weaver]

Thanks, David. I wondered about that. Also, how common are 4 tpi saws? I assumed this was a rip saw, hopefully correctly so.
Tom

Like marv, I haven't seen them nearly as often as 5-5 1/2, or maybe not as often as 6, either, though 5 to 5 1/2 (as stamped on the saw) far more often.

I have four rip saws, one is a 4 tpi. It is a nice saw to have for stuff thicker than 5/4 or so. It's definitely a lot faster if you lean into it, but the back side of the cut is rougher, especially if you rush it, too.

[Marv Werner]

Jim,

Are you referring to a positive rake angle? Is that the way you file your saws?

[Tom Winship]

Jim, if I look at a point with the handle on right, the angle of the tooth is about 8 degrees from veritical to the left (positive rake?).

I am going to file it to 0 degrees, I've decided.

The saw points are 1/4" apart making it 4 tpi or 5 ppi, corect.

[Pedro Reyes]

Jim, if I look at a point with the handle on right, the angle of the tooth is about 8 degrees from veritical to the left (positive rake?).

I am going to file it to 0 degrees, I've decided.

The saw points are 1/4" apart making it 4 tpi or 5 ppi, corect.

Tom, Google "Sawspectra" you'll hit Joel's site and download that very useful PDF file, should clarify and explain what is going on.

hope this helps

/p

[Tom Winship]

Pedro, thanks, I had seen that before. The saw has negative 8 degrees (I thought it was called positive.)
Anyway, I will change to 0 degrees and see how that works. Saw hasn't been used in 30 years probably.