R Groves & Sons, 16" tenon saw

Discussion in 'Forum: Saw Identification and Discussion' started by rob1713, Sep 2, 2018.

  1. rob1713

    rob1713 Active Member

    Messages:
    35
    I bought a box of tools today and in it was this very large steel backed tenon saw. After a quick scrape and light rub down of the spine I was pleased to see that it was made by R Groves & Sons. I was less pleased when I started to scrape the plate with a razor to find that it had a crack in it.
    I've never seen a Groves 16" back saw before and the handle is a little different to the norm with the lambs tongue being a bit 'dog legged'.
    My plan before spotting the crack was to keep it as a user so I've either got to file it down 1/2 inch or so or look for a replacement plate, do you think it's worth the effort
     

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  2. kiwi

    kiwi Most Valued Member

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    309
    Looks like a nice old saw, with its blank medallion and old style "dog leg lamb's tongue".
    The blade crack is inconspicuous (I don't see it), so I'd check that this crack actually affects performance before abandoning the plate or shearing off 1/2" of depth and re-toothing. [ I've known lots of things (and people) that are slightly cracked, but still perform their primary tasks quite adequately.]
     
    David likes this.
  3. Dusty Shed Dweller

    Dusty Shed Dweller Most Valued Member

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    93
    If I came into possession of an old Ferrari with a cracked block I'd have a go at it.

    Along the same lines, it's a Groves, a nice 16"er that is great for bench use. They don't grow on trees and they are absolutely top notch so try to save it. Flex the plate while holding it up to the light and see if the crack goes right through. Cracks continue to propagate so you'll have to shear/grind off the blade t0 the crack depth and re-tooth the plate - just check first that this will be possible because Groves' are often so highly tempered that modern files won't cut them. In that case you'd consider re-plating it.

    Cracks typically mean a bloody hard plate and often occur at the end of a cut when the saw kind of "catches" in the kerf and the user levers things sideways to clear the saw... watch out for it and concentrate on completing cuts cleanly without binding.
     
  4. rob1713

    rob1713 Active Member

    Messages:
    35
    Unfortunately the crack is all the way through the plate, its 1/2 " above the the tooth line just forward of the handle and shows up as a fine silver line on photo of the handle.
    I think I will go to the effort of trying to restore it to use as there will still be a good depth of plate if I take it back past the crack and re tooth.
    Now the only decision is whether to spend the afternoon filing it or look at cutting it. Has anyone here ever tried cutting a full length of tempered saw plate and achieved success? If so please share the experience.
     

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  5. Dusty Shed Dweller

    Dusty Shed Dweller Most Valued Member

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    93
    Don't over think it. Rule a line along the plate with a marker. Then I'd use a cheap little 25 mm cut off wheel in a Dremel-like tool to score a line the length of the plate, then snap it through the mark over the arise of my saw bench. Takes about 10 minutes, maximum. Wear ear, eye and breathing protection as the wheels get chewed up fast.

    Unless you're brutal you won't burn the plate (the wheels are too friable and you won't dwell on one spot will you?). You don't need to cut all the way through. Then tidy up with a grinder or files,

    Alternatively acquire a pre-prepared plate from another saw or one of the online suppliers.
     
  6. ray

    ray Administrator Staff Member

    Messages:
    619
    My preferred method of cutting saw plate is to clamp it up between two pieces angle iron, and use that to guide an angle grinder with a thin cut-off wheel.
    Use a file to remove the burrs from the angle grinder and joint it to square the cut afterwards.

    The angle iron acts as heat sink of sorts to keep the blade temper, although I don't know if that's even an issue.

    Regards
    Ray
     
  7. rob1713

    rob1713 Active Member

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    35
    Thanks for the tips gents. I opted to use a thin cut off wheel as I don't have a Dremel. A single light pass and it folded off nicely.
    I'm going to use the cut off section as a guide to file the new teeth. If I don't make a pigs ear of it I may post some WIP pics
     

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    Underthedirt likes this.
  8. Dusty Shed Dweller

    Dusty Shed Dweller Most Valued Member

    Messages:
    93
    There are many ways to re-tooth a plate but this one is about the easiest with basic tools.

    Darken the jointed plate edge with a dark permanent marker or engineer's blue to make life easier for yourself. Secure the guide plate next to the plate to be re-toothed (that's the hard part). Then use a sharp slim file to gently nick each gullet the length of the plate. Then you can dispense with the guide and get filing. You'll probably have to rejoint and finagle the teeth a coupe of times to get the spot on - assuming the original spacing was good.

    I'm assuming you're cutting rip teeth? I'd chuck about 3-5 degrees of rake in to make the saw run better.

    Oh, and allow plenty of time and you'll probably rag out a couple of files. Gulleting is tough on file edges, especially modern ones which are CRAP.
     
  9. rob1713

    rob1713 Active Member

    Messages:
    35
    I have now filed the plate flat and clamped it up in my saw vice behind the cut off section which I am happy to use as a template as the original teeth were level, nicely shaped and spaced at 9TPI. This suited me as I want to use this primarily for rip cutting larger tenons.
    Using the original cut off section as a template worked better than I thought, on the first pass I filed them nearly to full depth I redressed the new teeth and gave them a final pass and I'm happy with the result.
    DSD you were spot on with your prediction, 2 saw files now in the scrap bin
    I'll set the teeth and refit the handle and see how she cuts.
     

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  10. rob1713

    rob1713 Active Member

    Messages:
    35
    Today I put the saw back together and put some set into the teeth. I always start of with a small amount of set and increase it as necessary. Unfortunately 3 teeth broke on my first pass. All were in the area of the initial crack which suggests that the stresses from the original crack have weakened the plate in this area or that there is a fault in the plate in this area which may have been the cause of the original crack.
    I have decided to live with 3 missing teeth rather than lower the tooth line even further as they are at the back of the plate.
    The saw now looks much better and cuts very nicely and it will be interesting to see if this area of the plate gives any more problems as I use it.
     

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