Tips for drilling poly?

Discussion in 'Tech-Talk' started by uncle daddy, May 29, 2020.

  1. uncle daddy

    uncle daddy Strat-Talker

    Age:
    54
    Messages:
    133
    Joined:
    May 16, 2020
    Location:
    UK
    Anybody know the secret for drilling through a poly finish without it cracking off? I've been fine with smaller holes like pick guard screws, but when it came to bigger ones like the screws for the trem unit, it's been a nightmare. I did the painters tape, and the pilot hole, but still ended up with something I'd be ashamed to be seen with in daylight.

    Hayelp!
     
  2. Thrup'ny Bit

    Thrup'ny Bit Grand Master Curmudgeon Strat-Talk Supporter

    Age:
    61
    Messages:
    34,802
    Joined:
    May 21, 2010
    Location:
    Yorkshire
    Run the drill backwards.
     
  3. wrvond

    wrvond Senior Stratmaster

    Age:
    63
    Messages:
    2,371
    Joined:
    Mar 22, 2011
    Location:
    West Virginia
    And use an sharp wood bit. Metal bits are not good for wood.
     
    Thrup'ny Bit likes this.
  4. Triple Jim

    Triple Jim Most Honored Senior Member

    Messages:
    5,492
    Joined:
    Feb 27, 2018
    Location:
    North Central North Carolina
    A brad point bit would probably work well. They're sharpened to they make a small pilot hole, and the next thing to contact the surface is two sharp cutters at the outer diameter. Once they score the circle it's unlikely any chips will happen. You can sharpen a metal cutting bit like that if you know how, or you can buy them. McMaster-Carr has them in about any size you could want. There are discount suppliers too.

    brad_point_bits.jpg
     
    rgale and dbolt like this.
  5. archetype

    archetype Senior Stratmaster

    Messages:
    1,963
    Joined:
    Nov 26, 2016
    Location:
    Williamsville NY
    If I'm enlarging an existing hole I use a chamfering cutter by hand, not in a drill or drill press, to chamfer the hole until I expose wood. The chamfer ends up a bit larger than the final hole size. Run the drill through at the fastest possible spindle speed.

    It's still a gamble and I hate doing it. I've put a few chips back in with CA glue.
     
  6. Thrup'ny Bit

    Thrup'ny Bit Grand Master Curmudgeon Strat-Talk Supporter

    Age:
    61
    Messages:
    34,802
    Joined:
    May 21, 2010
    Location:
    Yorkshire
    He needs a UK supplier, if he doesn't have any.
     
  7. Triple Jim

    Triple Jim Most Honored Senior Member

    Messages:
    5,492
    Joined:
    Feb 27, 2018
    Location:
    North Central North Carolina
    Right, I hate when I don't notice the location! He shouldn't have a problem finding one with a search for "brad point bits" or "brad point bits uk".

    I would imagine that running the bit in reverse as you suggested would get through the finish OK, and then you could run it normally to finish the hole. That stuff can be like glass though. I've chipped mine just by taking the neck off.
     
  8. Thrup'ny Bit

    Thrup'ny Bit Grand Master Curmudgeon Strat-Talk Supporter

    Age:
    61
    Messages:
    34,802
    Joined:
    May 21, 2010
    Location:
    Yorkshire
    I just run a standard bit backwards and quite slowly through the finish. I often use a hand drill rather than an electric "whoops slipped" guitar destroyer...
     
  9. Believer7713

    Believer7713 The Pink Bunny Frankenstein Strat-Talk Supporter

    Age:
    46
    Messages:
    9,316
    Joined:
    Dec 27, 2016
    Location:
    KC
    I just use a really sharp drill bit and work slowly. Sometimes I put the bit in a pin vise to turn it with my fingers easier too.
     
  10. tinkertoy

    tinkertoy Strat-Talker

    Age:
    46
    Messages:
    382
    Joined:
    Feb 10, 2020
    Location:
    alpha centauri
    It this on older guitars (as in around the time poly came out) out, or all guitars?

    Not that I have drilled a ton of holes in guitars or anything, but I have assembled both my warmoths. I also stayed at a holiday inn express last night......

    I cant say I have ever chipped a finish. I am not sure if its because the paint is still soft or I am super awesome.

    I am hoping it's the latter, but suspect it's the former.

    And all done with a cordless drill and some drill bits like a barbarian.
     
    CigBurn likes this.
  11. CigBurn

    CigBurn You should see the other guy. Strat-Talk Supporter

    Age:
    62
    Messages:
    11,862
    Joined:
    Jun 22, 2014
    Location:
    Same Shed Different Day
    Thought you looked familiar...

    Conan the Guestarian.jpg
     
    tinkertoy likes this.
  12. tinkertoy

    tinkertoy Strat-Talker

    Age:
    46
    Messages:
    382
    Joined:
    Feb 10, 2020
    Location:
    alpha centauri
    That was quick!

    Nicely played too
     
    CigBurn likes this.
  13. jrbirdman

    jrbirdman Senior Stratmaster

    Age:
    66
    Messages:
    3,216
    Joined:
    Feb 3, 2016
    Location:
    Elk Plain, Wa.
    Sharp bit and tape