I had 84 holes to drill in three inch deep aluminum
for the injector runners. I was looking at a lot of time
spent in front of the mill. Perhaps 10 to 15 hours.
I found this drill in the Airgas catalog on  page 13.
Jobber length parabolic drill made in Germany.
Drills deep holes in aluminum lickity split.
Goes through aluminum like a hot knife through warm butter.
One continous down feed. Expensive at around $15 each but well
worth it.

I think Tracy farms out his three inch psru spacer blocks to a NC shop
but if not he could save a lot of time drilling all those long holes.

Paul Lamar
 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2003 All world wide rights reserved.