I have a small piezo mic designed to be inserted into the body of an instrument. The procedure is to drill a hole of the appropriate diameter (5mm), glue an internally threaded metal cylinder into the hole, and then the mic or a plug can be screwed into the metal cylinder. This was no bother with boxwood- I just started with a tiny bit, and kept enlarging the hole with successively larger bits until the desired diameter was obtained.
The mic works so well that I would like to do the same on a keyed blackwood instrument. Clearly there is a solution given that every blackwood flute has finger holes-I just don’t know if there are any special features of blackwood that set a trap for the unwary/ignorant.
Blackwood works pretty similarly to boxwood. It’s denser and oilier, but the grains are both extremely tight.
If you’re pleased with the way it turned out this time, I see no reason to change anything.
On the other hand, depending on your setup, if you noted the drill size needed, you might just want to use that size to begin with. That way there’s no uncertainty in where one hole overlays the previous one, and it reduces the possibility of the bit biting in a hole that’s just a bit smaller.
Favourite flute: the one I used is an Australian make “Piezobarrel”. You can also get a much more expensive German one made by Rumberger. It doesn’t require phantom power. I am using mine on an uilleann pipe chanter, which is hard to mic since the sound comes out the finger holes, so the mic has to be far away to get all the notes, and then there are feedback problems if the venue is noisy (think pub on St Patrick’s day…) For the flute, I just play into a vocal mic which works OK. My flute is an antique, and I don’t want to lower its value by drilling.
Chas: Your idea would be great if I had a drill press and the right side forstner bit.. The first time was easy because I was drilling a flat topcap of the chanter that I could remove and clamp. I am more nervous this time because my starter hole will be going in the body of the chanter, so I worry about the bit skidding more than I worry about binding…
I had difficulty with drill bits not making the initial hole exactly where I wanted them and also tearing too aggressively at the wood, sometimes splitting bits off beyond the diameter of the required finished hole, though that’s likely less of a risk with the dense wood you’re using. I found the solution to this with the sharp pointed burrs in this set: https://www.amazon.co.uk/gp/product/B08ZSSF7S9/ref=ppx_yo_dt_b_asin_title_o07_s00?ie=UTF8&psc=1 - they’re 6mm wide at the fat end, but you don’t have to go full depth. They go very slowly initially before gradually accelerating through, and they’re so fast at the end that they jump through and damage the opposite side of the tube if you’re using a hand-held drill. I always use these for making pilot holes now because if they’re slightly off target you can move them sideways with ease while drilling and get the location exactly right. I also use a knife point to make the initial entry point, pressing down and rotating it just to make sure the burr doesn’t jump away from that location.
Thanks for the ideas above. I like the look of the brad point a lot. My sense of caution says to ask around my friends to see if anyone has a drill press, and use a brad of the right size.
If this were to be done to a flute, I wonder if you could just make a second end cap to the headjoint with a hole in the center for the piezo? Then it would sit right next to the head joint cork.
Apparently it needs a small through hole to the bore (?) …but drilling that through a cork would seem more sensible than the flute itself (?) … though I guess many would prefer the neatness of an outside mount …
The only piezo I have used is on guitar, just simply cemented to the wood.