(Very) Tight Tolerance Turning

[danrudolph]

Looking at turning a small diameter (.040-.050) for a length of .125 with a tolerance on that diameter of +/- .0001 in 300 series stainless. We do a few +/- .0003 diameters, no big deal.

The stainless grade is my choice, as long as it's in the 300 series. My guess is bar roundness (or lack there of) is going to be the killer. Thinking a harder grade of stainless, like 316, would be good. Part is all turning, no drilling.

We are planning on 100% inspection on this dimension. What instruments would work for inspection?

What am I in for here?

[ProProcess]

Originally Posted by danrudolph ...We are planning on 100% inspection on this dimension. What instruments would work for inspection?...

What ever your customer will be using.

Originally Posted by danrudolph ...What am I in for here?

Less hair and a lot of "...well they checked good here..."

[brianpnh]

for inspection, i would use a window mic. graduated in .00005. good luck holding that dim!!

[gizmo_454]

Can someone say CLIMATE CONTROL?!

[petriej]

Centerless ground stock??

[DCogswell]

Ground stock is a must with the tolerance as tight as the grinders will agree to. Stationary GB; move GB to within .005" of the tool performing the operation.

If you must use a revolving GB then, grind your tool to bring the cutting edge to the GB.

Premium Cutting oil.
TiN coated tooling
Gage R & R study (internally & with customer)

And most importantly, order some incense & holy water from the Vatican and have the machine blessed.

[danrudolph]

Here's the update...

Customer is going to inspect using class XX ring gages for the go and no go. We would purchase ring gages to use as well.

Thinking about this, roundness should be less of a concern with ring gages than using a mic.