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

Without some sort of auto feed the task you have at hand is near imposable.

You might control the feed speed steady enough for some short period but being human
sooner or later your hand will involuntarily "jerk" and while it might not seem like
much, the "jerk" could easily quadruple the feed speed for an instant and in tough
material that's enough to hear the fat lady sing.


A thought did occur to me while writing the above and that is if you geared down your
feed enough, manual hand feed irregularities would not translate into such violent

(violent for a 1/8 th end mill)

bed movements. Thing is, if you go to all that trouble you might as well have a motor of
some kind drive it.