Hand saws tooth shape

[Bedrock]

I have two 20" crosscut hand saws - a Disston D8 and an S&J. The D8 has been well looked after and beautifully sharpened, although only a "1" is visible now to show how many TPI it had originally. That suggests that the toothing was to an odd number. Can that be right?
The S&J is 10TPI, has the reinforcing pin to the handle, albeit that it was originally somewhat uncomfortable and in that rather unpleasant bright orange varnish.
Both have taper ground blades and flex well, which I have always understood is a sign of good quality.

The sharpening on the S&J is not so good (me), but both cut very well, with that nice sharp rasp. However. in sawing to dimension on pieces of what was sold as "Croation oak", both left a splintery underside, which may now have to be cut back to avoid the rough edge.
Is there a refinement to the shape of the toothing which can be recommended to minimise this breakout?

I accept that oak is probably more prone to splintering than tighter grained timbers, but advice would be welcome.

Regards Mike

 

[bugbear]

In a cross cut tooth (made with a 3 square file) you could:

* increase fleam (make the teeth pointier and more knife like)
* decrease rake (make the teeth less aggressive)
* decrease pitch (make the teeth smaller)

All of these will have effects other than reducing tearout. It's all a compromise.

BugBear

 

[pedder]

Do what BB tells you or use a sacrificial thin board.

Cheers Pedder

 

[Fat ferret]

Do what BB tells you or use a sacrificial thin board.

Cheers Pedder

Agree.

 

[xy mosian]

Just in case, like me, you are not familiar with the term Fleam, here is the best explanatory diagram I have seen.
http://www.blackburntools.com/articles/ ... index.html
I am about to resharpen an S&J cross cut myself.
xy

 

[Trafalgar]

Ring porous woods punch out on the backside of a cut comparatively worse than other species. A thin, light backer board will always help but one other thing to keep in mind is that a poorly jointed saw will rag out on the exit side worse than one whose teeth are well-jointed. A saw with too much breast, if not handled correctly, can do this as well though this is a more unlikely cause.

BB's points apply as well though in the end just using a backer will be the most expedient solution.

Unless the tearout is horrendous remember that you're sawing wide of a gauged line and planing back to it and the plane will therefore take care of the rag in the end.

If the saw is tearing what almost amounts to chunks as it exits then you have one or a few teeth higher than the others. Fix this at the next saw filing.

If you're crosscutting then you need to saw slightly wide of a deeply incised line on both faces and both edges and work back to the finish line with a plane - freehand or on a shooting board. I prefer freehand since you can come in from both edges and eliminate the chance of spelching. The incised line is your guide for where wood needs to be removed during this process.

 

[Bedrock]

Thanks to you all for your advice. Will try this and see how I get on. On the smaller point, on the D8 only the "1" remains to indicate the original TPI. What is it likely to have been, given that it is apparently an odd number?

 

[AndyT]

On the smaller point, on the D8 only the "1" remains to indicate the original TPI. What is it likely to have been, given that it is apparently an odd number?

I reckon it could have been 10, 11 or 12.

It didn't have to be an odd number. This page gives some documentary evidence that these were all options on a 20" D8 at various dates: http://disstonianinstitute.com/d8page.html

 

[Bedrock]

The "1" is on it's side, facing the toe, hence I guess 11 TPI.

Thanks Andy

Mike