On 2009-05-16, Jim Wilkins wrote:
On May 16, 8:13*am, Bruce in Bangkok wrote:
On Sat, 16 May 2009 04:08:09 -0700 (PDT), Jim Wilkins
[reversing a motor?]

As far as I can remember reverse was never used for actual machining.

Cheers,

Bruce in Bangkok

In a discussion of 1 vs 3 phase motors, someone once posted that
several important lathe operations require instant reversing.

Maybe I never do anything important, but I've never needed to reverse
it without stopping first. The lathe stops very quickly at the end of
a thread when the belt tension lever is released.

This assumes that you have a belt tension lever within easy
reach. Not all lathes are made the same.

My 12x24" Clausing 5418 has the motor in the pedestal, and I
have to turn a knob several turns to open the door, and then bend down
and swing the lever from one side to the other to lift the motor and
relax the tension in the V-belt. Even relaxed, it still has significant
drive and will not simply stop -- at least until it throws the V-belt.

I presume that your lathe has a flat leather belt with the motor
mounted behind the headstock (common with South Bend lathes, at least.)

Some versions of my Clausing (but not mine) have a dog clutch
which allows switching from forward to stop to reverse while the motor
continues to run forwards. These also have a variable speed pulley
assembly controlled by a crank on the front of the pedestal.

Enjoy,
DoN.

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