drilling a 3/8" hole in my guitar body

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by merkaba22, Sep 19, 2008.

  1. merkaba22

    merkaba22 Member

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    I have a SG with a push-pull switch that I want to replace with a regular pot and 3 position switch. I need to drill a 3/8" hole (or slightly larger) for the switch and want to do this in a way that does not encourage the finish to crack when drilling the necessary hole.

    Why use a toggle when you can use a push-pull? http://www.thegearpage.net/board/showthread.php?t=442217

    It would be hard to clamp the surface of the SG flush to another piece of wood at least in view of the TOM studs, etc. and just drill from within the control cavity; although, if it is the preferred method using a small piece of wood could be arranged.

    Alternately, I wonder if using making tape in that area would work? And if so, do you drill from the outside (surface of the body) into the cavity or vice versa?

    Or, is there yet a better way to accomplish this?
     
    Last edited: Sep 19, 2008
  2. frankencat

    frankencat Guitarded Gold Supporting Member

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    Use a reamer or a round file and go slow. It will come out cleaner than a drill. And yes, use tape on the face of the guitar to protect it. At least that's how I do it.
     
  3. empty71

    empty71 Member

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    +1 on the reamer ;)
     
  4. mike80

    mike80 Member

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    Run the drill bit in reverse. That should minimize any chipping or splintering.
     
  5. merkaba22

    merkaba22 Member

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    Do you recommend drilling through the taped side (surface) towards the cavity or vice versa? Start with 3/8" or smaller and then either ream or work up to that diameter?
     
  6. 12guitdown

    12guitdown Member

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    I'd drill from the inside out because a drill bit pulls the wood UP when it's cutting. Also make sure you have a piece of wood clamped tightly to the face of the guitar. This will reassure any splintering of the face. Use a scratch awl to mark the center of the extra piece of wood. This will act as a guide for the bit and keep your hole on center. Put the drill on the mark and get the drill up to full speed before applying downward pressure. The faster the speed and the slower the drilling, the cleaner the cut will be. You do have a little margin for error, I say little, as the washer and nut cover that area. No big deal. But if you're limited with tools and experience then the reamer method is much safer. Remember to slowly and think everything through thoroughly before you begin and it'll turn out fine.
     
  7. merkaba22

    merkaba22 Member

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    That sounds like great advice -- thank you.

    btw: if I do clamp, will I also use masking tape?
     
  8. David Collins

    David Collins Member

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    Drill from the outside, with a sharp brad point bit (3/16"-1/4"), then ream to proper size. I'd advise though, that if you have to ask all these questions and are nervous or unsure of your skills, it would hardly cost anything to have a professional do it. Seems simple, and it is if you know how to drill a clean hole. Don't push too hard, keep it straight, use a sharp bit of a suitable style, clamped backing block can help, etc. Try drilling from the inside with a 3/8" jobber bit though, and you're just asking for a big finish blowout.
     
  9. merkaba22

    merkaba22 Member

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    Done a fair amount of wood work and have the tools -- I LOVE this guitar and just want everyone's 2 cents to confirm my approach -- you never know when you will learn something new:)

    Thanks again!
     
  10. 12guitdown

    12guitdown Member

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    Well? Did you do it?
     
  11. merkaba22

    merkaba22 Member

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    Ran out of time yesterday --- out of town today; maybe sometime this coming week -- thanks for asking:)
     
  12. Bob V

    Bob V Member

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    If you have a bradpoint bit I'd reinforce the advice to run the bit backwards slowly from the outside. That will score the finish and start cutting through the outer surface of wood. Then after the hole is started you can finish drilling forwards. Also the cleanest way to finish a hole is with a reamer - it will make it perfectly round and just the right size if you keep testing as you go. Machinist's reamers don't have much taper to them so you need a set of them, but there are common T-handle reamers that go from about 1/8" at the tip to nearly 1/2" at the widest point, and they're wonderful to have around.
     
  13. TD_Madden

    TD_Madden Gold Supporting Member

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    Listen to Bob...I messed up redrilling a pot hole on my Edwards Goldtop...sure it doesn't show under the knob, but I know it's there!
     
  14. TAVD

    TAVD Guitar Player Gold Supporting Member

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    Drilling a new hole: I use a forstner bit and then ream it if needed.

    Enlarging a existing hole: I use a step bit first to drill as far as I can without going to the next step, then finish with a forstner bit and reamer.

    Either way, drill from the finished side.
     
  15. walterw

    walterw Gold Supporting Member

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    wait, are you widening an existing hole or drilling a new one? if the former, 10 risk-free seconds with a tapered hand reamer and it's done. if the latter, it's david collins ftw. in that case, maybe a tiny pilot hole drilled from the inside of the cavity, like 1/32", to locate the hole while still allowing the brad-point bit to center in it.
     
  16. 12guitdown

    12guitdown Member

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    Well it looks like I'm outvoted here, not to mention some are luthiers too. :hide


    I'd say go with the majority.;)
     

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