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Hello,

I've tried a couple different types of countersink bits from woodcraft with just OK results on bridge pin holes. They all tend to chatter a bit and I end up having to try to clean the holes up with sandpaper. I read here that some folks like to use a carbide burr for this task. Any suggestions if this works well and what type? How about just bore a bigger hole a couple mm deep and then drill the rest of the way through with a smaller Brad point bit? The thread with the bridge for the Gibson has me thinking I can do a lot better on this next one.

Any feedback is appreciated.

Brad


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I use a standard 3/8" counter sink with 3/16" pilot -- the trick is to make a stop, I used a piece of nylon spacer CA'd in place, works great and not $35 --- if you know what I mean.

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Ken Cierp

http://www.kennethmichaelguitars.com/

Regular wood countersinks work only for certain species -- woods like Ebony usually work great but for other woods they simply can't be trusted. You want to use a single cut carbide burr like this one:

http://www.amazon.com/SGS-Tool-Company- ... detailpage

This works so much better than a countersink and has infinitely more control - just remember to go very slow. It also results in a very clean finish.

I use a fuller four flute countersink with a stop collar and a tapered drill bit.

+ 1 on the carbide bur.

http://www.carbideprocessors.com/90-cone-shape-carbide-bur-3-8-dia-1-4-shank-3-16-cut-length-single-cut-sgs-14950/

I'm a big fan of zero flute countersinks for this job. Smooth finish, slow cut, no chatter.

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Eschew obfuscation, espouse elucidation.

What rpm should I set the drill press in order to use a carbide burr correctly?


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Thanks, David. Then this slower in the drill press? Do you have a recommended RPM?

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I always chamfer with my hand drill, pedal to the floor.

Quick glimpse around 6:20. Usually a 5 second job.

http://youtu.be/HgkcA9ikHFQ

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Eschew obfuscation, espouse elucidation.

I didn't know what it was called, but that's what I've always used--much smoother cut than fluted countersinks or carbide burrs.

I use the Festool countersink. It looks kind of like Eric's. Expensive but it gives a great cut.

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Joe Beaver
Maker of Sawdust

Am I the only one who uses the StewMac countersink?Mine does a great job.

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Steve Smith
"Music is what feelings sound like"

Exactly, that's why I copied it -- the pilot and the depth stop make the use of that design a no brainer. No worries about chatter, repeat-ability etc. like some of the free hand options suggested. But again mine only cost about $6.00

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Ken Cierp

http://www.kennethmichaelguitars.com/

I use a standard twist bit, (7/16" - 1/2") and run it slowly "BACKWARDS" in my hand drill or drill press. The angle of the end of the bit makes a slight bevel. If you go forward, of course, it will dig in. But when you run it backwards, it just bevels the edge of the hole and burnishes it. Test it on scrap to get the size bit that gives you the bevel you like. Don't try this with a brad point bit or you will have a mess.

Be careful with any of the methods you use, if there are string notches already in the holes.

I got the Stew Mac one a couple months ago and there is no going back for me. They all work well but this one is just idiot proof.

Maybe it was just the zero flute counter sink I got years (10+?) ago, but it had a strong tendency to produce a chamfer that wasn't concentric with the hole.
I even tried modifying it so it had a smaller clearance angle and took a smaller bite.
The spiral carbide bur I use now I find crazy sharp and controllable. I use it super slow.

http://www.leevalley.com/en/Wood/page.a ... 42281&ap=1

I use one of these dedicated to the task.

OK, I have a zero flute and a carbide burr on the way. Test results from this weekend will be posted next week

Thanks for all the feedback!

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The StewMac countersink. I use my grandpa's hand drill to drive it. I've used it on ebony and Brazilian rosewood and it worked great.

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I've let on recently that I'm a big fan of hand work, literally. If you leave one fingernail to grow long enough (in terms of time, not length), eventually it will calcify to the point where you can use it to scoop the fibers out of woods even as dense as ebony. This is the approach I prefer because it leaves me feeling very connected to the work.

The results are stunning. The resulting countersink is so polished you don't even need to clean it with sandpaper. The surface has a nice organic quality with a certain je ne sais qoui that can't be matched by machining.

That's what I'm using, with the drill press as fast as it will go. Just use a light touch.

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Mike Fields

We need a Youtube video of this method in action!

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Once in a while you get shown the light in the strangest of places if you look at it right - Robert Hunter

I would like to see that video also. Could it be possible that James has been hitting the secret sauce?

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Joe Beaver
Maker of Sawdust

I'd love to guys, but I haven't been able to figure out how to really convey the method over video and think it would be frustrating to everyone in the end. For now, I'd just recommend you pick a nail, let it grow, and don't take any fish oil because it inhibits the calcification process. It helps if you tap your nail on the couch when you watch TV. Think of Jean-Claud kicking the tree in Kickboxer.

Stew Mac purpose-designed bridge pin countersink. Works perfectly.


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