Sorry typo. "Down to" was meant. Now if we can only get 0.005" that
might be ok. 0.006" maybe not so.
You might talk to shops- we have had some custom cores made (very
expensive in small quantities), but nothing really small- this was for
an application that was very, very special.
A note on communication terminology with shops- you'll most likely be
talking about "centerless grinding" rather than "machining" per se.
Maybe try All Diameter Grinding in Orange, CA 714-744-1200 .. if they
can't do it, they ought be able to point you to someone who can.
Grinding diamters down to a couple of thou (half of what you're asking
for) is not unusual. Maybe start with the minimum Fair-Rite can do-
0.5 or 0.75mm, IIRC).
BTW, Tim W., I now have a 0.394" dia x 0.394" diamond grinding bit in
hand (literally) and will hopfully try gapping an E-core over the
holidays. They recommend mist or flood. It would be nice to get close
to the 30K RPM limit, but I don't have a TP grinder <sad face>.
There's a 0.256" one that's rated at 60K RPM (4000+ SFM), 10-20x what
I can get with the 0.394 bit and the spindle of either of my mills. I
suppose I could try and clamp an air die grinder (noisy..).
Best regards,
Spehro Pefhany