I am going with Ryan V block and a fence on the DP. The V block will center the round just by setting it in and clamping the round to the V
block will keep you lined up in the block and then run along the fence on the DP. As far as clamping the round in just taping it to the V block should do the trick.
Yup - you would want to center the DP to the bottom of the V in the block once, but then anything round put into the V block is correctly centered as well. I would put a long/thin piece of drill stock into the DP center the V block on that and then bump the fence into alignment with the block and clamp the fence in place. Re-check the alignment (cause moving the fence may have shifted things) and you're good to go.
For testing the idea tape works well for "clamping" as Chuck noted. For long term a couple pieces of inner tube could be easily rigged up so they caught on some hooks and held the piece down which would be fast, easy and re-usable (maybe I'm cheap
).
Another self centering vise idea:
http://www.youtube.com/watch?v=PuVqrkd3UrQ Looks like it would be pretty easy to replicate
I like the lathe jig idea from a gizmosity perspective cause I think it would be fun to build but I'm unconvinced its a practical solution here for a couple of reasons. I think the most common setup would be something not altogether unlike this one:
http://www.youtube.com/watch?v=COsdJKt7NgM except drilling from the side.
This has a few problems I can see from a production setup in that you have to assemble/disassemble it every time you want to use it. This means re-aligning it and making sure that it is true on all axises. Having a dedicated setup on a DP seems like it would be less hassle and would allow you to quickly move from one station to another without having to get everything realigned with a fussy setup. Remember that the most accurate form of measurement is none at all, so if your setups can be self aligning or easy to align you're way ahead of the game.
If you did a deep V block (glue on higher side walls) you could set it up with a template that sat on top for your hole pattern as well. Basically have a stop at one end of the V so the flute self aligns to the hole pattern sitting over it, spring clamp it down, slide it into place on the DP table and drill through the plate with pre-drilled holes in it. If the plate was made out of mild steel it would last basically forever. This would remove almost all of the measuring and setup from the process. That assumes of course that you don't have to adjust the hole spacing on individual flutes (I suspect not, but am not an expert - I just read a couple of books a long time ago so
waves hands)