On Fri, 25 Apr 2014 07:23:27 -0500, Karl Townsend
wrote:

...
Well ... I've never used a LeBlond, but I have used a
Monarch, and would love to have one. (But beware that depending on age,
it may depend on tubes which are now hard to find and expensive when you
find them for spindle speed control. The original ones used a
motor-generator to produce the DC voltage to run the spindle motor, and
I'm not sure whether there were any tubes involved. The next generation
used transformers and tubes to produce the DC, and those are the
expensive ones to keep going. The generation after that used solid
state devices in a potted module to perform the same function. If that
fries, you are DOA. Finally, the latest ones (including many converted
by the factory from the older ones) use a three-phase motor and a VFD to
provide the spindle speed control.

Unless you are a Ned Simmons type, trash the DC stuff on these lathes
and put in a three phase drive motor and VFD. Not at all a difficult
project. I'd even suggest going this route and use the fact that the
drive is poor to negotiate a lower selling price.

Karl

I know I'm some sort of ilk (Gunner's told me so on several
occasions), but this is my first clue I'm also a "type." g In my
defense, what Karl is referring to is the fact that I kept the
thyratron drive in a 10EE that I was able to repair without too much
effort. I'll admit that part of my reluctance to scrap the old drive
had to do with the cool purple flashing of the tubes as they fired,
not practicality. I sold that machine several years ago to a guy who
drove from NJ to ME to pick it up. Last I knew it was still working
with the thyratron drive.

I did install a VFD in my big Monarch. Two actually; one for the
spindle, and one for the coolant pump.

--
Ned Simmons