In article , Gunner says...

" Traction drives depend upon friction between a speed adjusting
mechanism and specially shaped input and output plates to achieve
adjustable speed with relatively high efficiency. In one common type
of traction drive, the motor drives an input cone that transmits the
power from the cone to an output ring connected to the output shaft.
The speed adjusting screw moves the motor and input cone up and down
changes the point of contact between the cone and ring changing, the
speed ratio of the drive as much as 10:1. With another common type of
traction drive, a series of balls mounted on tiltable shafts press
upon the faces of the input and output cones. A speed adjusting lead
screw tilts the ball shafts to increase or decrease the effective
speed ratio of the drive transmission by as much as 8:1. Traction
drives are best suited for applications with steady state loading."

Right. But my suggestion was that he purchase a cone-pulley machine.
That's what started this CF off. A cone pulley machine has cone
pulleys and flat belts. Here's a photo of one of those handy
cone pulleys:

http://www.metalworking.com/DropBox/_2000_retired_files/Seneca1.jpg

another one:

http://www.geocities.com/noramm10566/59rear.jpg

As you have correctly pointed out, cone drives and cone pulley flat
belt drives are not the same thing. A cone drive would be a poor
choice for fitting a VFD, because a) it's already in principle
a variable speed machine, and b) they're pretty inefficient.

I would still suggest a flat- or v-belt, cone pulley (aka, step
pulley) setup, with a VFD added to the three phase motor to give
a very good true variable-speed machine. Seems like all the
fancy variable speed lathes (with the possible exception of
hardinge) all come with a host of wear issues, most of which
are only *slightly* sub-critical when the new owner takes
possesion. AKA 'that's why they were selling it in the first
place.'

Even you and I have had discussions about hardinge varispeed
mechanisms.

Jim


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