On Sat, 14 Feb 2009 11:49:26 -0600, F. George McDuffee
wrote:
snip
Check the back issues of the "Home Shop Machinist" or
"Machinist's Workshop" for exactly this project. IIRC this was
called a Swiss type holder.
http://www.homeshopmachinist.net/
snip

I checked my back issues and the article you want is

St. Louis, C. (2007 August/September). "New Light for your
Lantern Tool Post." Machinist's Workshop, 20.4, 6-15.

The article shows the standard rocker style tool holder and how
that works as well as showing an improved height adjustable
feature, which can incorporate the existing ring/rocker if
desired, but not required.

Note that there is no modification to the tool post or lathe if
this is a consideration.

The "Swiss" reference I recalled was to a Schablin manual
toolroom lathe.

Some cautions:

As is common in many hobby projects, the machining appears to be
more elaborate than necessary, and some avoidable problems are
created by buying material close to the finished sizes, leaving
no room for "service flanges" used to hold the work while
machining, but which are turned off, or the part parted off as
the last operation.

Three specific examples:

(1) The milled anti-rotation flats on the adjuster screw/sleeve
that fits over the tool post are not required. A much simpler
anti rotation solution is to drill and tap holes in the proper
location and install small [#8/#10] SHCSs. This eliminates the
need for a milling machine or lathe milling attaintment for this
part, although precision layout and careful drilling, possibly on
the lathe faceplate will be required for a close fit in the
compound [top] slide T slot. Get sufficient length of material
[1_3/4 OD + tool post ID + c. 0.010/0.020 [or solid] X 4 to 5
inches] to clamp in the three jaw, and part off the completed
part. This is an external 1_3/4 X 20 thread. For our
international participants I am sure that a 1.25 or 1 MM thread
will work as well. If you face the part, drill and bore the part,
externally thread the part, and then part off the part [c. 5/8
but your lathe may require different thickness], this will insure
that the faces are parallel and the thread is perpendicular to
the faces.

(2) While the vertical fluting on the adjusting nut is very
elegant looking, and I am sure works well, it requires a milling
machine and dividing head. A good coarse knurl will provide the
same function, and no finish at all may well be adequate. At the
very least a knurl eliminates the need for a milling machine and
dividing head, and it may well be possible to skip this step
entirely.

(3) If a longer piece [4-5 inches] of heavy tubing or even a
solid bar is purchased for the adjusting nut [2.75 OD X 1.70 ID],
it can be clamped in the three jaw chuck. This will have an
external knurl [or possibly nothing] with an internal 1_3/4 X 20
thread. I strongly recommend that you bore/drill the hole
through or at much deeper than required, and cut a recess/relief
for the tool to feed into. While it is possible to thread to the
bottom of a blind hole [after many years of practice] it is much
easier with through hole. If you face the part, drill bore, and
thread the part, and then part off the part [5/8 thick], this
will insure that the faces are parallel and the threads
perpendicular to the faces.

Good luck with your project, and let the group know what you
discover and how you make out.


Unka' George [George McDuffee]
-------------------------------------------
He that will not apply new remedies,
must expect new evils:
for Time is the greatest innovator: and
if Time, of course, alter things to the worse,
and wisdom and counsel shall not alter them to the better,
what shall be the end?

Francis Bacon (1561-1626), English philosopher, essayist, statesman.
Essays, "Of Innovations" (1597-1625).