Funny lathe mach'g update...
 

Awl--

And all what I lernt....

From the previous thread, had a helluva time drilling a 3/16 hole and then
getting a 3/16 rod to fit inside it w/o hitting a peculiar step.

Apropos of the advice in that thread, I reverted back to a previous
strategy, which involved pre-drilling w/ a 1/8 drill, and then finishing w/
a 3/16 4 fl endmill--mostly because I wanted a flat-bottomed c-bore. I had
gotten lazy, saying Ahh, forget about the flat bottom, just go straight w/ a
3/16 bit, and then all the subsequent problems.

Now there is no problem whatsoever--nice *controllable* fit.

So it seems that there *was* a chip/gouging problem w/ the 3/16 drill being
used by itself, as suggested, but which escaped me for the following
reasons.
First, similar drilling of aluminum on the lathe had not presented such a
problem.
Second, drilling brass on a milling machine was always a no-brainer, never a
problem.

In both these cases, chip clearance was never an issue because in alum, the
ribbon is sort of self-ejecting. In drilling brass on a mill, the spinning
bit ejects the chips.

BUT,
In a lathe, w/ a *stationary* bit in the tailstock, and w/ fine brass chips,
there is no spinning drill to power them up/out--they just sit there, and
bind/gouge.
I realized this today in re-sleuthing this thing out, as it dawned on me
that I had to *peck like crazy* w/ the 1/8 drill--cuz of zero rotation of
the bit.

Could not ascertain for sure whether this problem had occured at the depth
of center-drilling, as suggested by a cupla posters, but I think this
probably was not directly related, altho there might have been some
secondary contributions.

So the problem is solved, w/ the new realization of the visissytudes of
stationary drill bits.
Never a, uh, dull moment. :)

Appreciate all the feedback, hope the other person expressing similar
problems finds this useful.
----------------------------
Mr. P.V.'d
formerly Droll Troll