My "drill" for drilling tuner holes

Vespa Bob

Well-known member
Joined
Jan 27, 2014
Messages
587
Reaction score
12
Location
San Jose, CA
I don't own any forstner bits for drilling smooth, sharp tuner holes, so I fall back on an old model aircraft tool for the task - a brass tube sharpened at one end and chucked in my desktop drill press. The slight drawback of having to dig out the plug from the tube is worth the burr free, no tearout result. I also use sharpened brass tubes for fret marker dots. Does anyone else use them for drilling holes?

BobIMG_0090.jpg
 
That's a great idea and thanks for sharing.

Would you be so kind as to share also how exactly you mount the brass tube in the drill chuck without pinching and deforming the tube from the chuck's clamping pressure?

Thanks!

I tried something similar once with an aluminum tube but the sides of the tube eventually got crushed-in by the drill chuck, since after several tries with the chuck not as tight, the chuck would not spin the tube due to the friction from the wood being stronger than the friction from the chuck and this the wood holding the tube from turning.

In the end, I have used a Unibit (aka Step-Bit) fitted to a T-handle (which I put together myself), with great success, as in the pic below:

clhXuha.jpg
 
Like the same way.
Nearly.
Many airplane models buiding (oldtimer, hand launch glider, slope and so on...)...in an another life...
:)

I don't own any forstner or drilling smooth, sharp tuner holes, so I fall back on an old model aircraft tool for the task - a brass tube sharpened at one end and chucked in my desktop drill press. The slight drawback of having to dig out the plug from the tube is worth the burr free, no tearout result. I also use sharpened brass tubes for fret marker dots. Does anyone else use them for drilling holes?

Bob.
 
For most hole making I use my Liion cordless screwdriver (currently $14.95 at Aldi in Australia)

with either these bits for straight holes
http://www.bunnings.com.au/bosch-5-piece-1-4-hex-shank-timber-drill-bit-set_p6320144

or the step drill in this set on the far left,

http://www.bunnings.com.au/craftright-3-piece-speed-step-drill-bit-set-_p6360137

This magical little drill bit is almost but not quite perfect for drilling the grommet sleeve holes or sealed tuner base holes. The perfect thing is that the holes are the perfectly aligned and matched diameters to most of the tuners with either the step between the 6 and 8 mm for straight shaft with sleeved grommet tuners or the step between the 8 and 10 mm for the sealed tuners. The imperfect thing is that the steps are 7mm deep and the grommets and thick part on the base of the sealed tuners are usually about 9mm deep. Having that perfectly aligned and clean hole there makes for easy deepening though. With the sealed tuners just going a tad deeper with the step drill and having a 2mm deep 12 mm hole at the back is not too troublematic as it is covered by the tuner. One of these days I may hit the bit with a grinder to get rid of that problem.

The weirdest thing about this step drill set is that the whole set of three is about two thirds of the price of buying any single one of the drill bits by themselves.
 
That's a great idea and thanks for sharing.

Would you be so kind as to share also how exactly you mount the brass tube in the drill chuck without pinching and deforming the tube from the chuck's clamping pressure?

Thanks!

I tried something similar once with an aluminum tube but the sides of the tube eventually got crushed-in by the drill chuck, since after several tries with the chuck not as tight, the chuck would not spin the tube due to the friction from the wood being stronger than the friction from the chuck and this the wood holding the tube from turning.

In the end, I have used a Unibit (aka Step-Bit) fitted to a T-handle (which I put together myself), with great success, as in the pic below:

clhXuha.jpg

I have no problem with the brass tubing deforming in the drill chuck. It doesn't take much pressure to hold it in place. Aluminum, on the other hand, is too soft for drilling applications. Not only is it easily deformed, but it doesn't hold a sharp edge for very long. I like the idea of a step drill. I'll have to add it to my shopping list!

Bob
 
Last edited:
I own some super sharp forstner brad point drill bits and I have learned even with these things it is possible to get tear-out when drilling through peg head veneers. I once saw a video by Gorden of Mya-Moe ukuleles where he demonstrated how to drill tuners holes with no tear out. It is actually an old carpenter trick where you run the drill backwards for a few revolutions to score the wood before downcutting the hole. Works like a charm with any drill bit.
 
I use one of these to drill the tuner hole and the grommet sleeve all at the same time, perfectly aligned.
The tuner hole drilled is 5.55mm and I need 6mm, but it is very easy and accurate to run a 6mm twist drill down the hole.
The counter-bore part is very sharp and has a shear cut and seem to drill very clean holes in all sorts of peghead stuff.

http://www.mcmaster.com/#29445a23/=zb176s
 
Top Bottom