Thread: Looking for some advice on tuning up some saws (Disston, S&J, Tyzack)

You may contact Paul (Bushmiller) about this either for help or advice. If you feel up for it I posted a description of a fix here My First Boomerang Saw: Fixing a Compound Bend.

Cheers Rob, I'll give that thread a look!

Ha Ha Rob

You may have made the same slip we make with your country. Bueller is on the other side of the country (4200Km)!

Having said that, I am sure we can assist, but pictures are going to be essential. Actually, Rob has one of the best articles on straightening back saws that I have seen but I can't recall if it was posted on the Forums.

Regards
Paul

Thanks Paul, I'll take some pics the second I get home

Whats 4200 km between friends.

Not far at all when you say it fast

DaveTTC

Turning Wood into Art

Man its hard to get a photo of these bends. The dovetail saw wasn't as bad as I remember, it's more of a curve in the plate from back to tip than the waviness I described earlier.

Disston




Spear and Jackson




And the other two that I should be able to tidy up myself.

Bueller

Those bends are very mild and I know they can be straightened. For the hand saw definitely check out the link Rob posted previously. It is excellent. I hope that he can point you in the right direction with your backsaw also. It revolves around the way the back is pushed onto the saw. It is that movement that creates the tension in the saw plate, but he is so much better at explaining the technique than I.

The only things that I would add are that you should partially clean the saw plate before hammering, but not to the final finish. As Rob pointed out any contamination will make small indents. Secondly you will need a suitable hammer. It needs to have a large, rounded face if possible. A small hammer head tends to concentrate the blow and you have to more careful not to leave marks.

The trick is to use many light blows rather than a few heavy blows if you are to avoid "bruising' the sawplate.

Regards
Paul

Cheers mate, I'll start looking around for a decent hammer but I'm lacking any sort of decent metal surface to hammer on. Got any suggestions?

Scratch that, I just remembered I have an old vice off an X/Y table that should do the job.



A lot of the hammers I'm seeing have flat faces, could I possibly use a nylon faced hammer? They seem to have a more rounded profile.

Here's the backsaw method Tensioning a backsaw plate. Be careful with the vise, many are not really very hard and can lead to denting of the saw blade. Better to use an anvil or, as Paul does, a bit of railroad track.

I agree with Rob & Paul that the backsaw curve is most likely due to the spine being knocked out of whack. In my experience, that's far & away the most common cause of curvy blades. You do see the occasional saw that has had some nasty accident, evidenced by a distinct crease in the metal, where it's been bent, or had something heavy dropped on it.

I'd try tapping the spine off & re-seating it. Hold the blade firmly, but not excessively tightly, in a vise and using a bit of hardwood as a 'punch', tap it at several points to lift it off the blade. If your vise has spikey jaw inserts, use a couple of bits of soft wood so you don't mar the blade. While you have the back & handle off, it's much easier to clean the blade up, as well. More often than not, when you reassemble, simply tapping the spine on evenly will eliminate the blade curve, and your blade will end up nice & straight. The spine isn't usually banged on fully, but sits with the blade maybe two thirds to three quarters of the way into the slot. The actual amount varies, partly due to when/where it was made, but more likely, who's mucked bout with it in the interim. The best clue I've found is to see how far the spine sits down where it goes into the handle rebate, & try to set it at the same depth all along. Maybe not a very clear explanation, but I think you'll soon see what I mean when you get at it.

I don't think I'd get too worried about tensioning the blade of the backsaw at this stage of your saw rehabbing career. I don't know this for sure, and am prepared to be corrected, but my feeling is that few, if any, post WW2 backsaw blades were hammer-tensioned. They may have been tensioned by partial rolling, the way bandsaw blades are, but in any case, they can work very well without it. Getting it clean, sharp & properly set will make a world of difference.

My 2c.....
Cheers,

Originally Posted by bueller

Scratch that, I just remembered I have an old vice off an X/Y table that should do the job.



A lot of the hammers I'm seeing have flat faces, could I possibly use a nylon faced hammer? They seem to have a more rounded profile.

I would say no to the nylon hammer.
A nylon hammer will "just move the metal".
You need a steel hammer to stretch the metal in a controlled way.
Your vice should be ok ,just make sure it's clean, I run a mill vile over the anvil I have on the back of my vice.
There's even a video somewhere here of me doing exactly that ,at the saw sharpening class.
Ian may remember what I'm talking about.
One other thing ,if your wanting to try saw smithing .
Don't try it on your new favourite saw first.
Get a junk saw to beat on.

Cheers Matt

One other thing
I use what is. Called a planshing hammer
Try panel beater supply shops


Sent from my iPhone using Tapatalk

Probably the biggest issue is going to be the hammer. As Matt said a planishing hammer can be used and I am pretty certain IanW uses such a hammer too.

It occurs to me that a large to medium size ballpein hammer could also be used if you are prepared to curve the face of the hammer a little more than normal with something like a flap disc on an angle grinder. A big gentle hammer is what you would be aiming for. This is a link to the marvellous dog head hammers I got from Rob Streeper so you can get some idea of the camber across the face.

Care Package from San Antonio

Post #27 shows my "anvil" and post #28 shows the hammers.

Just a thought that others may wish to comment on is the hardness of a ball pein hammer. Will it be too hard?

Regards
Paul

Looking around online and it seems like planishing hammers are tough to come by in Perth, would one of the eBay cheapies do the job? It will probably be a couple of weeks till I get to it so not fussed on shipping times.



Beadsmith Planishing Hammer - for hardening and smoothing metals | eBay