Best Tool to Widen Pot Holes

Discussion in 'Luthier's Corner' started by LimaGuy, Apr 18, 2012.

  1. LimaGuy

    LimaGuy The Godfather Supporting Member

    Apr 21, 2011
    I assume this has been asked a million times but
    can anyone suggest which tool (type of wood file?) would be best to widen Pot Holes.

    I need to make 4 pot holes about 1.5-2mm wider on a bass with a matte finish.

    Thanks in advance for your suggestions.
  2. Bruce Johnson

    Bruce Johnson Gold Supporting Member Commercial User

    Feb 4, 2011
    Fillmore, CA
    Professional Luthier
    To make sure I'm understanding you, you want to increase the diameter of the holes that the pots go in, because you're putting in different pots, right?

    Well, the best way to enlarge the holes is with a piloted reamer of the right size. But, I'm assuming that you don't have access to one of those.

    So, the next best thing is to use a round file and enlarge them by hand. You want to find a round file that's fairly coarse and is close to the diameter of the existing hole. Work slowly, and keep the file straight up vertical. It's usually easier to wrap a cloth or paper towel around the middle of the file and hold it there, filing with just the tip.

    Tip #1: On each of the new pots, there should be a nut and a washer. Take off one of the washers and lay it down over the hole on the body. Use a fine pencil to draw a circle on the body around the inside of the washer. That will give you a guideline to work to as you are filing.

    Tip #2: When filing out a hole like that, it's real easy to accidently pop the file out of the hole and jab it into the surface of the bass nearby, causing a deep scratch. This will cause you to do a wild dance while screaming profanities! To avoid that, find a piece of cardboard and cut a small hole in it. Lay that down on the bass and do your filing through the hole, while watching your pencil line.

    Tip #3: Take your time and do it right. Keep testing the fit of the pots until they slide in nicely. Then get all of the wood chips out of the inside.
    wraub likes this.
  3. LimaGuy

    LimaGuy The Godfather Supporting Member

    Apr 21, 2011
    Thanks, exactly the info I was looking for. :)
  4. Jazzdogg

    Jazzdogg Less barking, more wagging!

    Jul 29, 2006
    San Diego, CA
    Good advice.

    I'd add:

    Tip #4: Use low-tack masking tape (green or blue) to protect the appearance surface before you commence filing;

    Tip #5: Use the file only on the push stroke to avoid chipping/tear-out of the appearance surface.