Filing a rip saw to crosscut

[jooleyen]

I just got a Disston No 7 dated to around 1875 for about $5 in good condition. I am having a hard time telling whether it's a rip or crosscut saw, as I don't have a crosscut saw to compare it and the teeth are dark with age. It's 10ppi and 20" long.

If it does happen to filed for a rip cut, can I simply file the saw as I would a crosscut and convert it to cross cut that way, or is there more to it than that?

Also, as long as the 6-sided (triangular looking) file is twice as thick on a face as the saw teeth are tall, can it be used? I have a file rated for a 6ppi saw and would use it on this 10ppi if that would be okay.

Thanks from a newbie sawyer

[bear_man]

10 tpi blades are crosscut — rip teeth are more in the 8 or 6 tpi range (he says without going to his shop).  Rip teeth are like little chisels, with the chisel-like teeth sharpened perpendicular to the blade and the direction of the wood grain.  Crosscut teeth come to a point and are meant to Cut the grain, which runs opposite to the direction of the cutting/sawing.  Someone MAY've sharpened rip-style on crosscut teeth, but I dunno why.
     As to the file to use, files are usually (always?) longer on a side than the teeth they're used on.  I can't say as I've Ever seen a file rated for a particular tpi, but I doubt I've seen everything even yet.   *he sighs meaningfully and grins*

[jooleyen]

Thanks for the help bear_man. I gave it a go and the small saw was crosscut. Easier to see in good lighting and after taking a stroke with the file.

[Bill Houghton]

There's more than you're likely to need, or even want, to know on this subject here: http://wkfinetools.com/tRestore/saw/sawsRestore-index.asp.  Another good resource is http://www.vintagesaws.com/library/primer/sharp.html.

Rip teeth are more upright:

than crosscut teeth:

, in addition to the angles Bear_Man mentions.

And, while handsaw* rip teeth are generally coarser than crosscut teeth - the common rip pattern is 5-1/2 points per inch, while crosscut teeth are generally 10 ppi and up, with the occasional 8 ppi saw - there's no particular reason why some past mechanic might not have wanted a finer rip saw for some application.

*Handsaw being the 20-26" long saws with no stiffening back on them, the kind you find at yard sales everywhere.

[bear_man]

Bill, thanks for weighing in.  The second link in particular is quite helpful to newbies on restoring saw teeth, in my estimation.  I was running only on memory when I replied..., and I forget why my memory ain't always what it oughtta be.   (O:

[Bill Houghton]

I was running only on memory when I replied..., and I forget why my memory ain't always what it oughtta be.

Yeah, I understand the memory is the second thing to go, after some danged thing that I can't remember what it is.