- 28 April 2017 at 3:32 pm #311513
I recently bought a steel back tenon saw that needs some TLC. Rust and muck is now being attacked, to do this properly I took the back off of the blade.
When done I noticed it wasn’t fully seated, tapering to the handle. If you know what I mean – I hope its clear in the picture of the detached blade.
Question is, is this normal? This is my first backsaw so I have no reference. If I were to fix it it would cover the top hole in the plate. Is this per design or a sloppy build?
It is a Knowles & co saw, from Sheffield.
Let me know your thoughts,
You must be logged in to access attached files.28 April 2017 at 3:51 pm #311517
looking at mine they do not bottom out ,I believe I read where they are not supposed to be all the way in as that is how you adjust them when they are bent ,by tapping the spine and resetting the blade28 April 2017 at 3:58 pm #311518
I believe that it’s normal.
I was reading recently on a website (unfortunatelly I don’t remember which one) that by default the plate of the backsaw should not be bottomed out into the spine.
In that way you have the otpion to tap the spine in order to staighten the plate if it’s curved.
You may find a relevant blog and video by Paul Sellers, on straightening backsaws.
If you tap the spine of the saw, in order to straighten the blade, either at once like PS does, or starting from heel to toe it’s more likely that the plate will go deeper in the spine at the toe end. I have restored three backsaws this month and I found the same tapering from heel to toe (in different degree on each saw though).
Two days ago I removed the handle of a modern Spear aand Jackson tenon saw, in order to reshape it, and I found that the blade was bottomed out into the spine for the whole length of the saw plate. Possibly this was done by me, because the plate was curved when I bought it new and I have tapped the back trying to make it straight (without any success, since the spine was curved as well). When I’ll put it back together I will pull the plate out a few mm and see how it works.
I hope I have helped.
28 April 2017 at 6:32 pm #311523
- This reply was modified 3 years, 1 month ago by Dionysios P.
Thanks for your help, that answers my question. I’m familiar with PSs straightening technique, but didn’t realise the plate wouldn’t bottom into the back.
It’s not entirily true btw that this is my first backsaw – it is the first ‘old school’ backsaw, but I did buy a new spear & jackson a while back (this one). I don’t like it because it has a bend in the back that I can’t seem to get rid of and the plate seems to be glued into the back. Or is this the one you fixed and am I mistaken about the glue?
Mic28 April 2017 at 6:55 pm #311525
It’s exactly that saw (the 12 inch version).
Possibly the back of the saw is curved in your case as well and therefore you can’t straighten the plate by tapping it.
I haven’t tried to separate the spine from the plate yet, but I am going to do it tomorrow and I will post a follow up.
Stay tuned 🙂
Dionysios28 April 2017 at 7:11 pm #311526Larry GeibParticipant
If the back isn’t a folded back do NOT try to remove it. It’s probable epoxied in place.28 April 2017 at 7:17 pm #311527
exactly , they epoxy plates that are milled ,not folded from I gather.29 April 2017 at 9:28 pm #311544
Follow up as promised.
The back on the currently available Spear and Jackson tenon saw is folded and not milled (I had this checked before even removing the handle).
As a result the spine was separated from the plate with ease and it’s reletively easy to put it back (you can remove the spine even with the handle on).
Possibly the plate is fully seated in the spine from the factory, judging from the trace left on the plate, and that makes the srtaightening process impossible.
Now when I put the saw back together I will push the plate half way deep in the spine (and I will gain a few mm of cut depth) in order to be able to adjust the saw by tapping the spine.29 April 2017 at 11:03 pm #311546
Good to hear that worked out. I’ll have a look at mine soonish to see if I can fix it into a workable saw.
Today I spent fixing the knowles an boy does a good tenon saw make a difference! Wrt seating, at heel end there’s a pin in the spine that prevents the blade to seat deeper. That makes sence as you’d be bumping into the handle which would introduce unneded stress in the wood there. Toe end I seated it halfway. Once inserted it needed one more tap on the spine to straigten it out.
The teeth (11 tpi) were uneven. By instinct I would remove them all and recut (as per one of PSs videos) as I did once before on another saw, but decided to attempt to fix them in place. This dude shows how to do that, but it looks easier than it is.. I flattened and aligned the tops and went to work. This was the most time consuming and difficult part of the day. The result is ok-ish, some teeth will need to resurface in next sharpening sessions, I hope.
The end result though is a dead straight tenon saw that cuts beautifully 🙂
This was Mic30 April 2017 at 5:12 am #311555
and you saved another good saw from the fireplace mantels30 April 2017 at 9:47 am #311563
I’m still fighting the handle from the woodworm though..
M30 April 2017 at 1:12 pm #311567
What are those ? I hear alot about them, mostly on the british side of the pond. Are they termites that get into the wood Or Different critters?it sounds like they are pretty destructive30 April 2017 at 7:34 pm #311573
A collection of critters. The handle will be fine with its 10 holes or so, but I don’t want them to go wild in my wood and tool collection. I don’t have much but what I do have is not for eating..
M30 April 2017 at 8:58 pm #311576Larry GeibParticipant
I though wormwood was what they put in absinthe…
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