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Enlarging control holes in a poly finish
http://luthiersforum.com/forum/viewtopic.php?f=10137&t=51040
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Author:  Conor_Searl [ Thu Sep 27, 2018 12:24 am ]
Post subject:  Enlarging control holes in a poly finish

A customer wants me to change out his pots on an offshore PRS. The posts on the alpha pots in the guitar are a little smaller than on the CTS ones I have. Any tips on making those holes bigger without chipping the poly? I’ve done it before on lacquer finishes by filing the rim of the hole a bit and then drilling backwards without any issue but would like to head any potential problems off at the pass.

Author:  Barry Daniels [ Thu Sep 27, 2018 9:12 am ]
Post subject:  Re: Enlarging control holes in a poly finish

This is what tapered reamers are for.

Author:  Conor_Searl [ Thu Sep 27, 2018 10:23 am ]
Post subject:  Re: Enlarging control holes in a poly finish

Barry Daniels wrote:
This is what tapered reamers are for.


Gotcha. Thanks Barry. While I wait for a tapered reamer to show up in the mail, (since I doubt I'll find one in town) would working up to the size of hole I need with drill bits amount to the same thing?

Author:  DanKirkland [ Thu Sep 27, 2018 10:26 am ]
Post subject:  Re: Enlarging control holes in a poly finish

Conor_Searl wrote:

Gotcha. Thanks Barry. While I wait for a tapered reamer to show up in the mail, (since I doubt I'll find one in town) would working up to the size of hole I need with drill bits amount to the same thing?


From experience, wait for the reamer. Drill bit's have a much higher chance of chipping things than the rramer.

Author:  Michael [ Thu Sep 27, 2018 10:29 am ]
Post subject:  Re: Enlarging control holes in a poly finish

Chipping the finish is the issue it seems. I would use a dowel wrapped with 80 grit sand paper and use a push stroke only.
Michael

Author:  Chris Pile [ Thu Sep 27, 2018 11:10 am ]
Post subject:  Re: Enlarging control holes in a poly finish

Rat tail file, sandpaper on a dowel, etc. Drills just invite cracking of finish.

Author:  Conor_Searl [ Thu Sep 27, 2018 11:30 am ]
Post subject:  Re: Enlarging control holes in a poly finish

Awesome thanks guys. Those are great suggestions.

As an aside, Stew Mac has tapered reamers for a variety of jobs and they are all around $80. Allparts has one generic reamer for about $6. Is there actually $74 difference in the quality? I'm pretty new to buying tools and I have noticed that you get what you pay for most of the time, I've also noticed the other part of the time you can buy really shiny looking toys.

Author:  Barry Daniels [ Thu Sep 27, 2018 2:30 pm ]
Post subject:  Re: Enlarging control holes in a poly finish

Stew Mac reamers only have cutting edges on one half of the body that prevents chattering, which is a very rough hole with large ridges on the sides of the tapered hole. It makes a huge difference.

Author:  Chris Pile [ Thu Sep 27, 2018 3:16 pm ]
Post subject:  Re: Enlarging control holes in a poly finish

Quote:
Stew Mac reamers only have cutting edges on one half of the body that prevents chattering, which is a very rough hole with large ridges on the sides of the tapered hole.


Those are called violin peg reamers. I have early ones with 1 flute for precision sizing.

Author:  Frank Ford [ Thu Sep 27, 2018 6:41 pm ]
Post subject:  Re: Enlarging control holes in a poly finish

Don't forget the step drill. It may look nasty ut it does a very clean job every time with little or no chipping.

Get the one with 1/2" max diameter:


Image

Author:  Chris Pile [ Thu Sep 27, 2018 11:38 pm ]
Post subject:  Re: Enlarging control holes in a poly finish

Frank won't steer you wrong.

Author:  Bosco Birdswood [ Thu Oct 04, 2018 2:44 am ]
Post subject:  Re: Enlarging control holes in a poly finish

Just playing devils advocate here but why not buy some new Alpha pots that fit the existing holes? Replacing the Alphas with CTS pots with make no difference to the sound unless they are faulty or of a different value to the replacements.


Sent from my iPhone using Tapatalk

Author:  Chris Pile [ Thu Oct 04, 2018 8:41 am ]
Post subject:  Re: Enlarging control holes in a poly finish

Because Alpha pots are crap?

Author:  Conor_Searl [ Thu Oct 04, 2018 10:25 am ]
Post subject:  Re: Enlarging control holes in a poly finish

Bosco Birdswood wrote:
Just playing devils advocate here but why not buy some new Alpha pots that fit the existing holes? Replacing the Alphas with CTS pots with make no difference to the sound unless they are faulty or of a different value to the replacements.


Sent from my iPhone using Tapatalk


Yeah, I know. The guitar was a PRS SE and the wiring was solid, clean, and well done, and I told my customer as much. But he wanted the upgrade. So I did it. The first thing he did when he picked up the guitar was roll the volume knob and said wow that feels better. :)

Author:  Photoweborama [ Sun Dec 09, 2018 9:35 pm ]
Post subject:  Re: Enlarging control holes in a poly finish

I use a dremel to enlarge them. Very precision edge that way.


Sent from my iPad using Tapatalk

Author:  DanSavage [ Mon Jan 07, 2019 3:54 pm ]
Post subject:  Re: Enlarging control holes in a poly finish

If you don't want tapered holes, you can use a model airplane prop reamer. These work extremely well for cleaning up tuner holes in head stocks, etc.

Available from Tower Hobbies for $15 each.

Image

Metric - 7mm, 8mm, 10mm (the first step is 1/4" (6.35mm)): https://www.towerhobbies.com/cgi-bin/wt ... XEGH6&P=ML
SAE - 1/4" 5/16" 3/8": https://www.towerhobbies.com/cgi-bin/wt ... XEGH7&P=ML

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