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Thread: Tenon Saw S-Curve

  1. #1
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    Tenon Saw S-Curve

    How straight does a tenon saw plate and tooth line need to be to cut square cheeks? I imagine it has to be next to perfect.

    I’ve refurbished a Disston 14” tenon saw and installed a new saw plate from Blackburn Tools. The original saw plate was non-restorable. The plate is seated in the spine well. The spine had been cranked on at some point in it’s life and I did my best to straighten it. Very carefully. I made a lot of improvement. I removed a twist and straightened the tooth line quite a bit. However, a very slight “S” curve remains. I might work on it some more, but I don’t think it will ever be next to perfect.

    What do you all consider necessary amount of straightness in your tenon saw plate for good joints?

    45B15E3E-F0C2-4660-AB30-CF53895F5574.jpg F47D21A4-BB02-4FC5-90D4-85AC7091715F.jpg 742C6745-5FBB-4D76-8810-5BE498FD649D.jpg

  2. #2
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    Welcome to the world of floating saw backs. While many point to the ease of adjustment in a blade as a virtue, it ceases to become so if it can't be adjusted. One of the many reasons that the solid, milled back is superior in every way.

    Some backs like this one may never be able to be straightened. The problem is a hard one, bending it to any degree puts a stress point on one side of the slot. You might consider removing the blade from the handle, grabbing the back in a vise with the blade installed and tweaking it to get it straight. At that point, the holes in the handle may not line up. In my experience, the back mortise usually causes more problems than the spine. Not all backs can be straightened. Some ideas that you can try to see if you can save this particular saw.

  3. #3
    Your skill will be what holds you back, not the saw. No, it does not have to be anywhere near perfect.

  4. #4
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    You mentioned "Cranked" near the toe. Was it just bent some or is/ was there a kink in the curved top of the spine? Folded backs are wholly dependent on that curved portion at the top of the spine. A bent spine can sometimes be straightened with a decent machinist vise. Otherwise, it does not have to be perfect, but it is certainly easier to use a saw with a straight tooth line as opposed to one that looks like a snake. It may be worth tracking down a beat up saw with a straight spine. Or contact someone that makes folded backs, like Florip tool works or TGIAG to look into a new spine. Eric at Florip Tool works is making spines from 4130 as well as brass. Best of luck to you.

  5. #5
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    bloomington il
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    You most likely just need to retention the saw plate. Simple fix here are some helpful links.
    https://www.youtube.com/watch?v=GBtzatDsDp0
    https://www.facebook.com/BadAxeToolW...0562170890104/
    http://www.badaxetoolworks.com/retension-a-backsaw.php
    there are more good write ups around just look for "retensioning a backsaw".
    Last edited by justin sherriff; 11-14-2020 at 3:14 PM.

  6. #6
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    Quote Originally Posted by Warren Mickley View Post
    Your skill will be what holds you back, not the saw. No, it does not have to be anywhere near perfect.
    Thanks. This is what I was asking. Hopefully other will chime in as well.

  7. #7
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    Quote Originally Posted by Ron Bontz View Post
    You mentioned "Cranked" near the toe. Was it just bent some or is/ was there a kink in the curved top of the spine?
    Nah. Just slight a bend and twist.

    Otherwise, it does not have to be perfect, but it is certainly easier to use a saw with a straight tooth line as opposed to one that looks like a snake. .... Best of luck to you.
    This one is far from a sidewinder. Maybe more of a night crawler. Not real obvious, but if looking for it you see it. The one tooth line photo is pretty representative. You mention easier to use one with a straight tooth line. It’s the “easier” part that worries me. Would a cabinetmaker or furniture maker use it?

  8. #8
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    Quote Originally Posted by justin sherriff View Post
    You most likely just need to retention the saw plate. Simple fix here are some helpful links.
    https://www.youtube.com/watch?v=GBtzatDsDp0
    https://www.facebook.com/BadAxeToolW...0562170890104/
    http://www.badaxetoolworks.com/retension-a-backsaw.php
    there are more good write ups around just look for "retensioning a backsaw".
    I’m well beyond that point. Thanks. Like I said, the plate is well seated in the back. I was asking about usability.
    Last edited by Kurtis Johnson; 11-14-2020 at 4:25 PM.

  9. #9
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    Quote Originally Posted by Kurtis Johnson View Post
    I’m well beyond that point. Thanks. Like I said, the plate is well seated in the back. I was asking about usability.
    See if you can saw out a tenon for a great fit right off the saw. If you can, your question is answered. If you can't, try a saw with a straight plate. If you can with it, then again, question answered.

    There is certainly no shame in owning a straight tenon saw.

    A joinery saw in pretty poor condition can cut wide of a line and leave material to be removed by some other tool. Presumably you have something else in mind so give it a go and see what happens.
    Last edited by Charles Guest; 11-19-2020 at 1:44 PM.

  10. #10
    Quote Originally Posted by Kurtis Johnson View Post
    Nah. Just slight a bend and twist.

    This one is far from a sidewinder. Maybe more of a night crawler. Not real obvious, but if looking for it you see it. The one tooth line photo is pretty representative. You mention easier to use one with a straight tooth line. It’s the “easier” part that worries me. Would a cabinetmaker or furniture maker use it?
    Are you talking about a current day furniture maker or an old time furniture maker? The modern day would probably set it aside and just order a new one off the internet while the old time woodworker would have repaired it the best they could and if it still worked they would probably continue to use it at the very least until they were able to replace it at some point. If they could get it to work well they probably would not have replaced it. I have a couple saws from my grandpa that were handed down to him from my great-grandpa that I am still trying to acquire the skill to use, but he could make the truest cut imaginable.

  11. #11
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    I had an old Disston that was similarly afflicted. I turned it over and tapped the steel back on the corner of my bench at the center of the saw. It put the tooth side of the plate in tension and straightened everything right out. YMMV.
    Sharp solves all manner of problems.

  12. #12
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    Nov 2013
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    United Kingdom - Devon
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    I'm not a paying member so can't see the the photos. If Warren can see them you can trust him. Likewise, as Charles said, no shame in buy or comparing it to something new.

    One of the reasons I don't contribute quite as often is the answer has already been posted. If my limited influence helps I'll happily chip in some more.

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