In article ,
Paul wrote:

Hey Joe

I just converted my 5904 Clausing to a VFD, how I did it is just one of
several ways so use or ignore whatever you want.

I stripped all the motor and motor mount brackets, the counter shaft
with the clutch/brake, and the speed control on the top of the headstock
off the machine, as well as the original electrics (except the drum
reverser switch). A new motor mount bracket was fabricated to position
the motor at the old counter shaft location using the mounting studs for
the counter shaft assembly.

The VFD I acquired came in a nice enclosure and was then mounted on the
back of the base cabinet, where the original junction box/disconnect
was. I wired the original drum switch (controlled by the
forward/off/reverse lever on the front) to the VFD's forward and reverse
inputs. I purchased a die cast project box and an appropriate pot (from
Fry's Electronics) for speed control and mounted them on the cast boss
where the original hydraulic speed adjuster was. I also replaced the
original 2 hp 1740 rpm motor with a 3 hp 3450 rpm motor driving the
spindle with the original size cogged belt, the motor pulley is now half
the size of the spindle pulley. The VFD high and low frequencies were
programed to approximate the speed range obtained with the original
hydraulic speed control. Accel/decel times were originally set to 2
seconds but the decel time was reset to 5 seconds to avoid overcurrent
trips caused by the inertia of the spindle and chuck. A braking
resistor will allow the preferred 2 seconds, I'm scrounging one at this
time.

So far the conversion is a big plus, much less vibration and noise as
compared to the mechanical drive. I used to have finish problems when
turning aluminum that I could never track down and I always suspected
the mechanical drive to be the issue even though it was in good
mechanical order. I now get beautiful finishes on aluminum and
attribute this to the elimination of the stiff variable pulley belt, I
think the cogs or slots in the belt were the cause of the finish issues.
The spindle can be 'plugged' from forward to reverse with no issues,
other than the too long decel time, I recently had to turn a thread to a
shoulder and found it much easier than before due to the better controls.

I have some pictures of the project and will figure out how to post some
to the dropbox eventually.

This sounds like a very good conversion, but is a future project.
First, I will get the lathe going in its present form, and use it for a
while, for the experience.

The pictures (plus the text of this email) would make a nice addition to
the dropbox.

That said, the bottom shaft on the variator does wobble badly, and I bet
it needs that famous plastic bushing.


I have some opinions on tool posts for this machine if you want to hear
them also.

I would certainly be interested.


Have fun with the new machine!

Thanks,

Joe (Grease-Face) Gwinn