I'm Curious and Need a Clue

[Harold Beck]

Folks,

I have seen several references to "tensioning a saw blade" in posts about handsaws. Could someone explain to me what this means? Is it done to panel type saws, backsaws or both? How does it relate to flattening a kinked saw blade?

Thanks in advance for any help.

HB

[harry strasil]

the blades are hammered, which work hardens and puts tension into the blade. Its also used to straighten blades, on large saw mill circular blades, the blades are tensioned (hammered) for a certain speed.

[Joel Goodman]

Do a search for Bob Smalser's post about straightening and or rehabbing saws. He imparts, as usual, a lot of valuable information.

[Joel Goodman]

Here's the link http://www.sawmillcreek.org/showthread.php?t=63325&highlight=straightening+saws

[Harold Beck]

Thanks for the explanation and link. I take it this is then something for handsaws without backs, correct?

Thanks again,

HB

[Joel Goodman]

I think that you would use this technique on a backsaw to straighten the sawplate with the back removed. I would like to hear about this from anyone who has experience as I have a backsaw that needs a slight straightening and was thinking about giving it a try.

[Luke Townsley]

I tried straightening an old back saw that wasn't quite straight. It is probably about as bad as before, but it is different now. ;-)

Part of my problem was that I bent (bent as in along the length like a banana) the soft folded steel back taking it off to rehab the saw and was never able to get the blade to seat properly in it even after doing my best with my limited tooling to straighten it (and I did get it fairly straight), so any straightening tended to be overridden by the pressure of the back turning it one way and the other.

Also, I didn't do the best job hammering out the saw plate.

[Joel Goodman]

The back on my saw (a D4 Disston) is straight as is the top of the sawplate. It's a little section near the teeth that is a little bent. How hard was it to get the sawplate out of the back?

[Michael Faurot]

I think that you would use this technique on a backsaw to straighten the sawplate with the back removed. I would like to hear about this from anyone who has experience as I have a backsaw that needs a slight straightening and was thinking about giving it a try.

I've tried the technique that Bob Smalser talks about and I personally have not been able to master it. Mr. Smalser does a good job of explaining things, but the mysteries of straightening spring steel saw blades have eluded me.

I would strongly recommend that you not try this on your backsaw, if that saw is at all valuable to you in either in a monetary or sentimental sense. Instead try the technique on something you don't care about, like something inexpensive found at a flea market.

[Luke Townsley]

In my case, getting the blade out of the back was quite difficult and not worth it, at least not with the vise and screwdriver I used.

[george wilson]

Joel,I described exactly how to straighten a back saw somewhere on this forum.Briefly,if the blade has a wave in it,clamp the front of the blade in a vise,and tap the back of the saw to stretch the blade tight again. They sometimes have slipped a little. I got one of my finest backsaws cheap that way. It was wavy. Dealer thought it was done for. A very early Groves saw.

To straighten a saw whose CUTTING EDGE is curved,clamp the saw by the tip of the back UPSIDE DOWN in a vise. Adjust a crescent wrench to fit the back. Use leather not to mar the back if needed. Twist the back with the wrench as if you were going to make a twist drill out of the back (Though not that extremely). Keep tweaking the back till the cutting edge is straight. Then,the back will not be curved,or look messed up,and the teeth will be nice and straight. We had to do this to most of the back saws we made in Williamsburg while we were assembling them. We had to invent(or re invent) the process,too.