old racer

[Dr. Robotnik]

Oh and these are an absolute pig to machine!!!!

Start with the larger recess first and use a rod that's a larger diameter.
then cut the center , and last reduce the outer diameter.

That way you keep the structural stiffness till the end of the operations.
(Don't know enoug about machining to be sure it is possible to do this way though )

They are still a pig to machine! That is a very deep recess and a very thin wall.

[BTracer]

Did you know that the average central corneal thickness [of the eye] is 0.5mm? Just thought I'd pad my postcount a little.

Glad that helped. Let me know if you need any remeasurements. Very interested to see how those come out Dr. Robotnik!!