@KeroZen , I did enlarge the heater and battery holes for batch 2, and onwards. I am also employing some strategies to acclimate each wood block at a low humidity before the final machining. I think what happened with batch 1 was after I machined the two holes, they shrunk just a tiny bit, and likely continued to shrink for the last year or so, depending on the wood species.
The amount of shrinkge is something I really did not expect, since the wood blocks are so small. I guess this is part of the on-going learning experience.
Once the wood has shrunk once, it shouldn't really shrink again, so it would be a one-time fix to enlarge the holes I think.
Apparently high-end woodwind instrument makers recommend sending flutes back after a number of months to ream the bores again to enlarge a bit after they shrink. Seems this is a one time operation that's done after the initial break in period.
I have read that some makers will pre-shrink the wood in drying cabinets to stabilize it before final reaming of the bore, seems like it works well for them, and it's where I got the idea to do the same.
If you would like to enlarge your battery hole I can send you the materials to do it safely and easily without any worry about causing damage. It'll be a dowel with slightly cushioned sandpaper wrapped around it and glued in place. This goes fairly quickly, and I could include a photo tutorial with it as well. It's as simple as insert, and twist. The key is really to use the padded sandpaper, the right grit, and the right size for the hole. Setting up that tool correctly is where the skill comes in, using it is rather simple.
This is how I would do it, so the process is the same either way, but if you'd me to do it for ya, no problem there at all! Just let me know.
One thing that stands out to me is the fact that your Nomad is African blackwood. Since the wood is so dense and resinous, the natural drying process can be extremely slow. I have indeed noticed the most movement with A. Blackwood.
Also, question about the SS stem. In use, if you were to take the stem out immediately after your draw, how hot is the stem near the middle. And how many draws does it take to heat up the stem? Thanks for any input!