Announcement

Collapse
No announcement yet.

How to increase the inner diameter of a plastic knob

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • How to increase the inner diameter of a plastic knob

    I've got a plastic knob whose inner diameter is too small to fit the shaft of the potentiometer i want to use.

    Is it possible to increase the knob inner diameter by drill the hole wider with the appropriate sized bit? Or instead, use a dremel with a sanding pad fitting on the lateral surfaces of the dremel tip to sand the existing hole to be wider? Is one method more fool-proof than the other? Is there a third option I should consider?

    The knob is designed so that there is solid material all around the existing hole vs the hole just being a flanged design surrounded by empty space, so theoretically the knob should be able to withstand some drilling/dremeling without instant collapse.
    Sanford: "The hardest part about tone chasing is losing the expectations associated with the hardware."

  • #2
    Re: How to increase the inner diameter of a plastic knob

    I have drilled out knobs before. You just have to be slow and careful not to drill through.

    Maybe just order some new knobs?
    -Chris

    Originally posted by John Suhr
    “Practice cures most tone issues”

    Comment


    • #3
      Re: How to increase the inner diameter of a plastic knob

      Yeah be careful
      EHD
      Just here surfing Guitar Pron
      RG2EX1 w/ SD hot-rodded pickups / RG4EXFM1 w/ Carvin S22j/b + FVN middle
      SR500 / Martin 000CE-1/Epiphone Hummingbird
      Epiphone Florentine with OEM Probuckers
      Ehdwuld branded Blue semi hollow custom with JB/Jazz
      Reptile Green Gibson Custom Studio / Aqua Dean Shire semi hollow with piezo
      Carvin Belair / Laney GC80A Acoustic Amp (a gift from Guitar Player Mag)
      GNX3000 (yea I'm a modeler)

      Comment


      • #4
        Re: How to increase the inner diameter of a plastic knob

        Originally posted by Ayrton View Post
        I have drilled out knobs before. You just have to be slow and careful not to drill through.

        Maybe just order some new knobs?
        Originally posted by ehdwuld View Post
        Yeah be careful
        Glad to hear that drilling seems to be a safe and effective way to go. Thanks guys.
        Sanford: "The hardest part about tone chasing is losing the expectations associated with the hardware."

        Comment


        • #5
          Re: How to increase the inner diameter of a plastic knob

          Are you sure it's too small? Or is it just a different knurl pattern? There are two different knurl patterns in knobs to fit the two different knurl patterns on pots...one to fit Asian made pots (Alpha, etc) and one to fit American pots (CTS, DMZ, etc).

          If your knob is a solid color you can get away with drilling it out. If it is transparent with the color coating on the inside of the knob you can't do it. In any case you need to be extremely careful because the drill bit will grab in the soft plastic and pull the bit all the way through in an instant and ruin your knob.

          It is best just to buy the correct knob for your pot.
          Originally Posted by IanBallard
          Rule of thumb... the more pot you have, the better your tone.

          Comment


          • #6
            Re: How to increase the inner diameter of a plastic knob

            If it’s a split shaft pot, you can gently squeeze the shaft a little to allow the knob to fit.

            Unless one is metric and the other imperial


            Sent from my iPhone using Tapatalk

            Comment


            • #7
              Re: How to increase the inner diameter of a plastic knob

              Originally posted by GuitarDoc View Post
              Are you sure it's too small? Or is it just a different knurl pattern? There are two different knurl patterns in knobs to fit the two different knurl patterns on pots...one to fit Asian made pots (Alpha, etc) and one to fit American pots (CTS, DMZ, etc).

              If your knob is a solid color you can get away with drilling it out. If it is transparent with the color coating on the inside of the knob you can't do it. In any case you need to be extremely careful because the drill bit will grab in the soft plastic and pull the bit all the way through in an instant and ruin your knob.

              It is best just to buy the correct knob for your pot.
              No threads involved. Solid shaft pot, knob is meant for aolid shaft - has a set screw.
              Sanford: "The hardest part about tone chasing is losing the expectations associated with the hardware."

              Comment


              • #8
                Re: How to increase the inner diameter of a plastic knob

                Originally posted by kingswebe View Post
                No threads involved. Solid shaft pot, knob is meant for aolid shaft - has a set screw.
                Yes, you cab drill those out. I do it with Hipshot knobs to fit on Bourns pots.


                Sent from my iPhone using Tapatalk

                Comment


                • #9
                  Re: How to increase the inner diameter of a plastic knob

                  If you have a highly tapered stepper bit or a Dremel with a jig/dremel stand it's a very easy job.

                  But I'm guessing you are going old school -so mount the knob securely and move up in 64ths or 32nds with bit selection until it works.
                  “For me, when everything goes wrong – that’s when adventure starts.” Yvonne Chouinard

                  Comment


                  • #10
                    Re: How to increase the inner diameter of a plastic knob

                    A "stepper bit" won't work, you need as close to a flat end drill bit as you can get.

                    The ideal way to do it would be start with conventional drill bits and drill up to final diameter (NOT in 32nds" or even 64ths"...way too large, the bit will grab the plastic and destroy it). A couple thousandths" at a time, 128ths" at most. Then finish off with a milling bit (flat bottom) of the correct final diameter.
                    Originally Posted by IanBallard
                    Rule of thumb... the more pot you have, the better your tone.

                    Comment


                    • #11
                      Re: How to increase the inner diameter of a plastic knob

                      Originally posted by GuitarDoc View Post
                      A "stepper bit" won't work, you need as close to a flat end drill bit as you can get.

                      The ideal way to do it would be start with conventional drill bits and drill up to final diameter (NOT in 32nds" or even 64ths"...way too large, the bit will grab the plastic and destroy it). A couple thousandths" at a time, 128ths" at most. Then finish off with a milling bit (flat bottom) of the correct final diameter.
                      I just did this with a stepper a few weeks ago. -On the GK style plastic knobs that have the gray cap so the stepper easily widened the channel and protruded out the other side with the gray cap off.

                      Second, you can absolutely do this with 32nd or 64th bits . -I used to this in my sleep as a kid when adding weird knobs to solid posts.. I think the difference here is Guitar Doc is giving you the more correct Luthier approach, I was giving you the home solution because as indicated I said I'm guessing you are going old school without specialty tools.
                      “For me, when everything goes wrong – that’s when adventure starts.” Yvonne Chouinard

                      Comment


                      • #12
                        Re: How to increase the inner diameter of a plastic knob

                        Originally posted by NegativeEase View Post
                        I just did this with a stepper a few weeks ago. -On the GK style plastic knobs that have the gray cap so the stepper easily widened the channel and protruded out the other side with the gray cap off.

                        Second, you can absolutely do this with 32nd or 64th bits . -I used to this in my sleep as a kid when adding weird knobs to solid posts.. I think the difference here is Guitar Doc is giving you the more correct Luthier approach, I was giving you the home solution because as indicated I said I'm guessing you are going old school without specialty tools.
                        Thanks, that makes sense.
                        Sanford: "The hardest part about tone chasing is losing the expectations associated with the hardware."

                        Comment


                        • #13
                          Re: How to increase the inner diameter of a plastic knob

                          Oh no not a step bit

                          I used a normal drill set in 64's
                          Found first the one that fit best the original hole
                          Then next size up by hand
                          Slowly
                          No drill motor
                          If you just do a small step wit each bit
                          It is easy to drive by hand

                          No running out into your other palm
                          No running out the top
                          None of that nonsense
                          EHD
                          Just here surfing Guitar Pron
                          RG2EX1 w/ SD hot-rodded pickups / RG4EXFM1 w/ Carvin S22j/b + FVN middle
                          SR500 / Martin 000CE-1/Epiphone Hummingbird
                          Epiphone Florentine with OEM Probuckers
                          Ehdwuld branded Blue semi hollow custom with JB/Jazz
                          Reptile Green Gibson Custom Studio / Aqua Dean Shire semi hollow with piezo
                          Carvin Belair / Laney GC80A Acoustic Amp (a gift from Guitar Player Mag)
                          GNX3000 (yea I'm a modeler)

                          Comment


                          • #14
                            Re: How to increase the inner diameter of a plastic knob

                            Yes, by hand seems like a logical and safe way of doing this.
                            Dave, Ambassador/Writer/Artist for Seymour Duncan

                            Comment


                            • #15
                              Re: How to increase the inner diameter of a plastic knob

                              If you attempt this by holding the knob in your hand, I suggest running the bit in reverse and move up in size gradually.
                              -Chris

                              Originally posted by John Suhr
                              “Practice cures most tone issues”

                              Comment

                              Working...
                              X