Best way to drill into gloss finish

[Barticus]

As the title reads, I’m looking for recommendations on the best way to drill into a clear gloss finish without cracking, damaging or chipping the surface.

I need to add a couple of three-way toggle switches and another 3/8” shaft pot to a clear gloss finish.

What should I be using, a small Forstner bit or Brad point… or?

 

[RichterScale]

Will the nuts be recessed, or just on top with a washer?
Is it a newer or older finish? Poly? Nitro?

 

[Barticus]

New poly for one and new Nitro for the other and yes just on top with a washer/nut.

 

[SoonerBill]

I've always had my best luck on painted metal or wood with Unibits.

 

[RichterScale]

New poly for one and new Nitro for the other and yes just on top with a washer/nut.

Don't put all your eggs in my basket, but just based on general experience, as long as the finish isn't really old/hard/brittle and as long as it's not an aggressive auger type bit that bites and pulls itself into the wood like a maniac and as long as it's a nice new sharp bit, just a standard general purpose bit should cut through cleanly.
But definitely wait for the folks that have cut a new hole through a guitar finish 100 times to chime in.

 

[Matt Liebenau]

Tape where you’re going to drill, a good, sharp Brad point or Forstner bit isn’t a bad idea. If you’re using a Brad point or Forstner you can gently run the bit backwards to help score the paint before you drill. After you drill peel the tape off towards the hole to help prevent chip out. Last, have some CA and matching touch up paint handy because sometimes even when you do everything right…

 

[dwizum]

I like Freud forstner bits, or other brands that have a similar "wavy" serrated edge, for cutting through finishes. I find it's much less likely to chip than bits that have just two teeth opposite each other, or a more saw like serrated edge.

But I think this is one of those things that's easy to overthink and as long as I had a reasonable bit (i.e. not aggressive) that was sharp, I'd just use it.

 

[thisSNsucks]

Run the bit in reverse to score the finish, then go normal rotation to drill through.

 

[micguy]

Run the bit in reverse to score the finish, then go normal rotation to drill through.

Add to this a sharp bit, and you're good.

 

[darwin-bass]

My though is to use a drill press. Running the bit in reverse is a great idea. Oh, wait, I just realized my new drill press won't run in reverse :-(

 

[Beej]

My though is to use a drill press. Running the bit in reverse is a great idea. Oh, wait, I just realized my new drill press won't run in reverse :-(

I usually just tighten the chuck and then turn it by hand in reverse.

 

[1n3]

If I'm concerned about chipping a brittle finish, I'll first penetrate with a burr, until my countersink is the diameter of (or slightly larger than) the hole I want to drill.

 

[Matt Liebenau]

I usually just tighten the chuck and then turn it by hand in reverse.

What @Beej said. Turn the chuck or even just the bit itself if you’re careful by hand. It doesn’t take much to score the finish.

 

[jacko]

If you're drilling into the cavity, try to clamp a piece of wood behind where you want the hole. This will give the bit something to drill into so it doesn't start splintering the wood in the cavity.

 

[Turnaround]

My though is to use a drill press. Running the bit in reverse is a great idea. Oh, wait, I just realized my new drill press won't run in reverse :-(

Rotate the chuck in reverse by hand as you feed the quill forward. The idea is to score the finish so you don't need power to do that.

 

[Dust2Dust]

A scorching hot ice pick

Wait, ask me again sometime when I haven't been drinking

 

[Barticus]

Thanks all for the input, I definitely have what I need

 

[Dust2Dust]

Good luck

 

[Giraffe]

A guy I apprenticed with would score the finish with an exacto blade before drilling through it. It was a fairly tedious process involving a small pilot hole at ground zero, and a dowel with a centering pin in the end. He set the centering pin in the small pilot hole, then settled in for a careful, slow scoring of the finish around the circumference of the dowel. He didn't go all the way through the finish. When he was done he taped the area if the surface was curved, and sometimes clamped a piece of scrap over the hole if the surface was flat.

He used a sharp bit and took three or four passes to get the full diameter of the hole going, slowly just touching the workpiece and checking his progress.

No chips. Scoring the finish is a PITA but it produces glitch free results, even in brittle old nitro.

 

[Ethereal Thorn]

I run in reverse until I burn all the way thru the finish it works better then just scoring it for me