[m-134b]

Ok, here's a question for you guys.... I have some parts that require a deep hole to be drilled with a concentricity of + - .005 TIR. I already posted in the RFQ forum, but if nothing comes through in that manner, how would you suggest going about this without breakin' the bank (I.E. EDM sinker or wire)

Ken

[psychomill]

How deep, what Ø, what material, what machine (you were thinking), what quantity, how many different parts with different holes, etc, etc....

[dxxx]

boring is the full proof way

[m-134b]

Shortest part is 6" with a .250" hole that needs to be held +-.003 in diameter. Aluminum

The intermediate is 11" long and 4140 steel. three varaitions, one has .250 hole, the other has .375 hole..... the third variant is of 6AL-4V TI with .375 hole.

Longest is 14" with a .400" hole with the same diameter and concentricity requirements.... Aluminum

Ken

[Geof]

I think you are well within "gun drilling" territory. Here is a Wikipedia description for you:

http://en.wikipedia.org/wiki/Gun_drill

Don't let the name confuse you, gun drilling is a generic term for drilling deep, accurate holes.

[m-134b]

Agreed. I did a google search and pulled up several companies for quotes, but they aren't interested in doing such short run stuff apparently.... I'm looking at just a few pieces.

Ken

[timlkallam]

I had some 6 inch deep .25 dia in alum. to drill in my lathe. I bought a gundrill from sterling gundrills for $80 .It worked great it ran straight within .001 and had a mirror finish.
http://www.sterlinggundrills.com/dee...undrills.shtml

[m-134b]

Awesome, thanks for the link!

Ken