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Thread: Long Core Bit for Wood

  1. #1
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    Default Long Core Bit for Wood

    Anyone have a source for a long hollow core bit? I need to remove 3/8" square steel boat nails for a sample inspection, and I want to core them out and replace with a glued in hardwood trunnel.

    In the past I have found a long screw removal tool in large sizes, but now I can't find anything other than small stuff from amazon or woodcraft. Anybody remember the name of the company I'm looking for? They have been mentioned here in the past I believe.

    I would like a 1/2" diameter, about 4" long.


  2. #2
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    Default Re: Long Core Bit for Wood

    If you can't find a commercial one, you could get a piece of 4130 tubing, file the teeth, and harden it.

    https://www.mcmaster.com/pipe/materi...-steel/od~1-2/

  3. #3
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    Default Re: Long Core Bit for Wood

    Maybe not in your price range but this outfit might have something that’d work:

    https://www.buerkle.de/en/ice-borer#similar

    I like the 4130 tube idea myself, even if you had to have a shop weld in a shank that’d fit the drill you’ll use to run it. For a 1’ length @ < US$8 + shipping you’d get enough for 3, maybe 4 ‘custom’ hollow coring bits.
    Last edited by sp_clark; 04-12-2021 at 04:33 PM.

  4. #4
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    Default Re: Long Core Bit for Wood

    4130 might not be very hardenable. Look for an alloy with at least 0.4% carbon, the more the better.

  5. #5
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    Default Re: Long Core Bit for Wood

    Just weld 1/2 inch tube to the standard core bits.

  6. #6
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    Default Re: Long Core Bit for Wood

    In a pinch, Iíve ground teeth in a hardware store roll pin for the purpose.

  7. #7
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    Default Re: Long Core Bit for Wood

    My local woodworking wholesalers are E.B. Bradley and Wurth/Louis & Co. They may have Seattle area branches. They certainly have equivalents. Call a local cabinet shop and ask who they buy their hinges and drawer guides from. If the wholesaler won't sell direct, go thru the cabinet shop.

    Or try Hafele. (mail order - retail & wholesale)

    Fisheries?
    David G
    Harbor Woodworks
    https://www.facebook.com/HarborWoodworks/

    "It was a Sunday morning and Goddard gave thanks that there were still places where one could worship in temples not made by human hands." -- L. F. Herreshoff (The Compleat Cruiser)

  8. #8
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    Default Re: Long Core Bit for Wood

    depending on how many you need to do you may not need bother with hardening

    Or cut and weld a holesaw to a pipe.

  9. #9
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    Default Re: Long Core Bit for Wood

    I think I found what I was remembering. Unscrew-ums. They have 1/2" diameter 4" long, exactly what I'm looking for. But my square nails aren't going to turn. I've never used one, anybody had success with such a thing? I'd be happy to have it barely touch the nail, just core the wood out. I'm not looking to back out a screw like they are intended.

    https://tltools.com/collections/unsc...-2-unscrew-ums


  10. #10
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    Default Re: Long Core Bit for Wood

    Any chance the nails would have a 'bow' or bend, which might complicate removal ?



    Rick

  11. #11
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    Default Re: Long Core Bit for Wood

    a 3/8" square has a hypotenuse of 17/32" so it will hit, but what about the head? Now I see that's the outside diameter. How can that work?

    Is there any way you can just haul that sucker straight out?
    Last edited by Gib Etheridge; 04-13-2021 at 12:49 AM.

  12. #12
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    Default

    Quote Originally Posted by hawkeye54 View Post
    Any chance the nails would have a 'bow' or bend, which might complicate removal ?



    Rick

    Having removed . . . a lot of old iron boat nails, I can attest that any expectation of their having gone into the wood in any way resembling straight is . . . optimistic.

    I'm sure they went through the planking straight, but what happens once they hit oak frames is another story.

    We were sectioning the old frames and splitting the sections off the nails so we could drive them out from the inside before bending in new frames. A straight nail was the exception. Some might as well have been clenched with a clenching iron. Had to clip them flush to the inside of the planking with end nippers so we could drive them out with a punch and hammer.
    You would not enjoy Nietzsche, sir. He is fundamentally unsound. ó P.G. Wodehouse (Carry On, Jeeves)

  13. #13
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    Default Re: Long Core Bit for Wood

    Quote Originally Posted by Gib Etheridge View Post
    a 3/8" square has a hypotenuse of 17/32" so it will hit, but what about the head? Now I see that's the outside diameter. How can that work?

    Is there any way you can just haul that sucker straight out?
    They were 3/8 square when new, but these days the boundary between metal and wood is blurred. Actually they are tapered, 3/8" at the top probably about 1/4" at the bottom. The heads are mostly gone, and will be easy to core through what is left I imagine.

    I will have to round the corners of the fastener somewhat with the cutter. Crooked nails might complicate things, but these were pretty hefty when new and going into drilled holes so hopefully they aren't too bent. Maybe that's optimistic.

  14. #14
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    Default Re: Long Core Bit for Wood

    I had the same idea with the hundreds of iron plank fastenings into the sawn frames on my boat, which were still doing a good job but the heads were rusting out through the topside paint. I obtained cylindrical tools like those illustrated, but the guy at the yard, whose experience and ability I trust completely, found the plan impractical. He suggested using an angle grinder to cut back the nail heads, which created longitudinal slots in the planks which were then filled with epoxy. Ugly I know. Bronze screws were inserted between each pair of nails. We did the 500 nails above the WL only. This is all now done. I’ll let you know how it lasts. I guess the builder in 1937 never expected her to last this long.

  15. #15
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    Default Re: Long Core Bit for Wood

    I can make you one, not too big a deal, composite bi-metal hole saw/seamless hydraulic tubing, what ID do you want?

  16. #16
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    Default Re: Long Core Bit for Wood

    Quote Originally Posted by Canoeyawl View Post
    I can make you one, not too big a deal, composite bi-metal hole saw/seamless hydraulic tubing, what ID do you want?
    Wow that would be really cool. I think something around 1/2" ID would be best case scenario, as it wouldn't require cutting much metal except right at the head. I can probably be flexible to work with available materials if needed.

  17. #17
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    Default Re: Long Core Bit for Wood

    You're going to need an OD to match available plug cutters.

    Jeff

  18. #18
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    Default Re: Long Core Bit for Wood

    I have made smaller ones out of steel brake tubing, quick and easy.

  19. #19
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    Default Re: Long Core Bit for Wood

    Quote Originally Posted by jpatrick View Post
    You're going to need an OD to match available plug cutters.

    Jeff
    I'm guessing J just wants to get the old nails out and then will finish to correct size with another bit. - cheers, Mark

  20. #20
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    Default Re: Long Core Bit for Wood

    "J.Madison has exceeded their stored private messages quota and cannot accept further messages until they clear some space."

    canoeyawl at hot mail

  21. #21
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    Default Re: Long Core Bit for Wood

    JM, as mentioned above Unscrewem's is the outfit that makes the store bought version, and theirs are based on roll pins, with reverse teeth ground into the end, we have used up many, many of those, and have taken to making our own, 1/2 an hour at Mcmaster Carr website will find you a few dozen 'blanks' of assorted sizes to sharpen up, we use a thin abrasive cut off wheel to cut crude teeth, generally doesn't have to be all that perfect to work...One trick some old rough neck from the past showed me is crazy, but fun; old golf clubs are available at the Goodwill store for a quarter a piece, if you notice, many of them use chromed hardened steel graduated shafts, get yourself a dozen and with that same cutoff wheel, pick the section that seems to be the right size, cut off a few sections, 5 or 6 inches long, cut those same crude reverse teeth in the business end, and chuck the resulting 'core-cutter' up in your battery drill, and gingerly try and cut around the fastening you need out. There is a lot of Hail Mary involved in the removal of old fastenings, more so with old boat nails, so be mentally prepared for some considerable percentage of defeat... Cheers, Steve

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