Strange TPI?

[tvrgeek]

One of the saws I am doing is a 12 inch back saw. Odd thing, at least to me, is it is 8 TPI...
Does anyone have an explanation of why such a course TPI on a short back saw? I am most likely re-cutting it to 12 or 14. That is if I can find a hack saw that in not bi-metalic but still can cut a saw blank.

 

[pop-pop]

Maybe sawing the cheeks of a rabbet in a riser for a stair tread to be let into? That would be a rip cut where 8TPI would be appropriate.

 

[Mike Davis]

Why do you need a hacksaw?
At first I was thinking template for filing new teeth, but bi-metal wouldn't matter for that.

 

[Graywolf]

As far as to why, I’m not certain. But to cut new teeth you only need saw files.

 

[tvrgeek]

As far as to why, I’m not certain. But to cut new teeth you only need saw files.

Going to use the saw kerf method Sellers and Wright show. Made up a little spacing block as I did not have much luck making the guide Sellers shows. Using a saw to extend the bottom of the gullet also take a lot of load off the file. Oh, Wright says the wavy set on a standard 32 TPI hack saw blade is OK and I don't need to get a non-bi-metal and hammer it flat. Should get some tomorrow.

 

[mdbuntyn]

Blackburn Tools has printable templates that may be useful: Blackburn Tools - Saw tooth spacing templates

 

[tvrgeek]

Blackburn Tools has printable templates that may be useful: Blackburn Tools - Saw tooth spacing templates

Yea, is you can see well enough and hold your file accurately enough. Check out the video Wood By Write did using the little block jig.
The saw handle templates are super.

 

[Graywolf]

I generally joint the saw down, in this case just enough to start a new tooth pattern. I use the guides like you can find on Blackburn tools site. I just use the file the same as you would use the saw. It’s one less tool and very accurate.

 

[tvrgeek]

I don't have that level of skill yet. Part of my problem is my vision.
I do wonder, with repeated sharpening's, the teeth migrate a little, so the deeper gullet may wind up going under the leading edge of a rip pattern. After all most of our joinery saws are rip. I'll do one with the jig and see how it turns out. I have a second one that was totally mangled I have already jointed smooth.