On Feb 16, 10:58*pm, GeoLane at PTD dot NET GeoLane at PTD dot NET
wrote:
What depth of cut is safe to take with a HSS end mill of 1/8" dia, and
how fast can you feed in mild stee without breaking or quickly dulling
the end milll? *The ROT of that I'd read in a book years ago was 1/8th
of the end mill diameter as the depth of cut (0.015 for an 1/8" mill)

I don't have power feed, and have never had coolant, except flood
coolant (what a mess) the few times I ran the horizontal part of the
mill. *[1940s vintage Hardinge Universal horizontal mill with a
Bridgeport C head in the overarm hole for vertical milling - not very
rigid, but it's what I have] *Any technique to use to do hand feeding
of the table?

Thanks

RWL

I can get away with 0.050 depth but prefer 0.025 for such a fragile
tool. The manual feed on my well-worn Clausing 8525 is sensitive
enough to feel the cutting resistance and I control it with light
finger pressure rather than trying to hold a speed. The inertia of the
dial evens out the impulses from each flute cutting.

Once I have the feel for the cut, I speed up the mill and use the same
pressure.

Jim Wilkins