Drill bit size for inserts?

Discussion in 'Tech-Talk' started by greezy strings, Apr 4, 2021.

  1. greezy strings

    greezy strings Strat-Talker

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    I have 2 inserts for a tail piece that are 12.9mm ( about 1/2in.) diameter.

    what size drill bit should be used? or is there a rule of thumb for how much smaller the drill bit should be compared to the inserts so there is a tight fit?

    Thanks!!
     
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  2. Triple Jim

    Triple Jim Guy Who Likes to Play Guitar Silver Member

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    My first thought would be to check with the manufacturer of the inserts. I can't imagine they don't have that in their instructions.

    My guess would be that since 12.7mm is 1/2", that's the size they would say to drill.

    As a last resort you could drill a hole in a scrap of wood and try an insert in it.
     
  3. ThreeChordWonder

    ThreeChordWonder Strat-Talker

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    Um, what kind of inserts?
     
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  4. Dibbs

    Dibbs Strat-O-Master

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    What Triple Jim said. You can always make that hole a little bigger, but if you make it too large, you can't make it smaller again. I'd take it slow and careful.
     
  5. CeltRocka

    CeltRocka Senior Stratmaster

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    Theres an old saying " measure twice, cut once" I would drill a scrap piece of wood - maybe 12.5mm -check for fit - too small it will tear the wood
     
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  6. MartinC

    MartinC Strat-Talker

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    +1 - the only way I have found to reliably size critical fitment holes is to practise on some scrap wood.
     
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  7. Believer7713

    Believer7713 The Pink Bunnyman Frankenstein Silver Member

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    +2^^^^^Practice on a block of wood once you drive it in that block and it is good and snug and no damage has happened, you can pull it back out and then work on your axe with what you know. Use a drill press and do not attempt it by hand would be my advice (ask me how I know). I would also tart with a 1/2 inch bit and check it from there. Remember, the wood will expand some to make for a tight compression fit.
     
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  8. Bob the builder

    Bob the builder Most Honored Senior Member

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    Kinda a rule in general.
    Test on scrap pieces.
    Don't wanna screw up the piece you need
     
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  9. Sarnodude

    Sarnodude Most Honored Senior Member

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    Preferably with a drill press , and while using the depth stop feature.
     
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  10. CB91710

    CB91710 No GAS shortage here Double Platinum Supporting Member

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    And a Forstner bit if one is available in the correct size. Very, very clean hole, they don't grab, and don't tear out.
    For the inserts, you want the hole to just clear the inner diameter of the splines. You can measure that with a good digital caliper and then use a drill of the same size.
     
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  11. StummerJoe

    StummerJoe Senior Stratmaster

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    Can't give better advice than already given.
     
  12. vid1900

    vid1900 Most Honored Senior Member

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    If we are talking about the brass 1/4-28 insert bushings that Fender sells, they say to use a 3/8" hole

    BUT, I'm not sure we are talking about the same thing, so let's see some pics....
     
  13. StratUp

    StratUp Strat-O-Master

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    Nail on the head. Go to Horrible Freight and buy the Digital Caliper. Around $15 on sale, $20 when not. You will never regret having it. Trust me, it's one of those tools you buy and then can't understand how you lived without it.

    Measure between the splines - that's the ID you want. Then find a hardware store/supplier that sells drills in "index" sizes. You'll usually need to use a drill index chart on the web to find out what size you need before you go to the store - they often just have the index numbers on the display.
     
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  14. Scott Baxendale

    Scott Baxendale Senior Stratmaster Gold Supporting Member

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    The rule of thumb is: use a dial caliper to measure the diameter of the part of the insert that goes into the body. Lock the caliper to that size, then get your drill bits and find the one that is ever so slightly smaller than your caliper setting. Then use tape on the bit to set your depth so the insert goes all the way into the body without bottoming out, but not too deep. Then with a small block of hardwood and a hammer lightly tap the block on top of the insert until it is at your depth.
     
  15. rmackowsky

    rmackowsky Strat-Talk Member

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    Or buy them on Amazon for seven bucks.
    https://www.amazon.com/dp/B07ZFBCNJF/?tag=strattalk05-20
     
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  16. CB91710

    CB91710 No GAS shortage here Double Platinum Supporting Member

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    And for reference on those cheaper calipers...
    Take the battery out when you aren't using it.

    They are auto-on when moved, and part of the circuit is still alive when the display is off.
    I've had a number of them and every time I'd reach for one, the battery was dead.

    I wrote it off to the foam padding touching the "on/off" button, but then it happened when I left one out.

    Started removing the batteries and I haven't replaced one in probably 5 years.
     
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  17. StratUp

    StratUp Strat-O-Master

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    That Amazon version looks like it hasplastic jaws. Hard to tell but that wouldn't be a feature if they are.

    I never had a battery issue with mine. Past five years on the original... although they gave me a spare with it. Also, I accidentally leave it on half the time and it times out and powers itself off. Maybe they made some revisions in the circuitry before I got mine.
     
    Last edited: Apr 11, 2021 at 9:34 AM
  18. rockon1

    rockon1 Senior Stratmaster Silver Member

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    I use a 3/8ths with 10mm. I would go one size smaller than 13mm- whatever that is. Plus one on trying on scrap first!
     
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  19. Believer7713

    Believer7713 The Pink Bunnyman Frankenstein Silver Member

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    That would be 1/2" which, I believe is 12.7mm.
     
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