On 30 May 2015 02:59:22 GMT, "DoN. Nichols"
wrote:

On 2015-05-29, wrote:
On 29 May 2015 03:02:12 GMT, "DoN. Nichols"
wrote:

On 2015-05-27, Bob Gentry wrote:

[ ... ]

The same as my Rockwell/Delta 7" shaper (a descendant of the
AAMCO).

What this means is that they cheaped out and used some 16 TPI
shaft (not even an Acme thread, but a more common V-thread) as the feed
screw here. I've been tempted to try making something more reasonable.
But a 10 TPI would be way too coarse for that small a diameter. (Wrong,
after looking and measuring it, it is 3/8" diameter, not the smaller
diameter that I though that I remembered).

[ ... ]

Hmm ... they *do* have 1/2-10 Acme taps, so maybe you could go
that way. Since you would have to make the base of the compound anyway,
make it thicker, so you could tap it 1/2-10, and make a new bearing
plate for the mount of the screw to the crank and dial to offset the
center line to match. But the taps are up near $100.00, too. :-)
#04794103

At least the design is for a right-hand thread, the left-hand
taps are even more expensive. :-)

And -- the 1/2-10 rod is less expensive, at least. :-)

Enjoy,
DoN.
Greetings DoN,
If a person wanted to replace the 3/8-16 vee thread with an Acme
thread form a tap is not required. The stub Acme thread form would
work fine in this application and the minor diameter of a 3/8-10 stub
Acme thread is .315.

The problem being that the existing thread in the dovetailed
base of the compound is already 16 TPI, and changing to 10 TPI would
mean irregular areas where the two threads remove metal from different
places, thus weakening the thread overall, and making it wear out
faster.

If a person had the skill to grind a 60 degree
thread single point tool and use this tool to make a 3/8-16 nut then
this same person would have the skill to grind a stub Acme single
point tool and could single point a 3/8-10 stub Acme thread. The
tougher part would be single point threading a long lead screw because
it would need support while threading.

Without pulling the compound apart, I can't state the length of
the leadscrew with any certainty, but I doubt that the working part is
any longer than 3".

The bearing nut and the crank with dial both thread onto the
shaft, so you would also need to replace those parts so you could thread
them properly.

At 3" length, and 3/16" diameter you might be able support it
with a half point dead center, if you took gentle cuts.

A follow rest works well for
this, I know because I have done this type of threading many times.

I've done it too. Including the time I made a test cross-feed
leadscrew for my Clausing, and when I went to test it with an old nut, I
discovered that I forgot to make it left-hand thread as needed. :-) At
least this uses right-hand thread on the compound.

The tough part is adjusting the follow rest as it wears. Lubing steady
and follow rests can be problematical. I solved this problem by
putting an oiler on my steady and follow rests. I use the old type
with a glass reservoir and a sight so the oil flow can be observed. I
direct the oil flow with a piece of piano wire that I stuff up inside
a small diameter tube that the oil flows from. I pull the wire out so
that it just barely clears the work. The drops of oil follow the wire
and land directly where I want it to land.

That sounds like a nice system. Thats for the description.

Enjoy,
DoN.
Greetings Don,
You're welcome. When I put the oilers on the steadys I just drill and
tap the steady for the pipe thread size of the oiler. For the steady
on my 14 inch lathe I drilled a 1/4 pipe hole into the part of the
steady that holds the vertical rest. So the oiler screws into a 90
degree elbow that screws into the steady. I then drilled a 1/8 hole
that intersects the 1/4 pipe hole and pressed a 1/8 O.D. stainless
tube into the hole and the wire then goes into the tube. This lets me
guide the oil drops to exactly where I want them.
Eric