On 2012-03-26, Noddy wrote:
On 27/03/2012 4:51 AM, Jon Anderson wrote:

Have you considered swapping the entire head?
If the bolt hole pattern is the same you're part way there. You'd need
to pull your head to verify the mating dimensions. Likely the biggest
issue would be the worm wheel for side to side adjustment assuming the
series II has one.

HI Jon. I'm going to try a straight swap today, as the lower halves of
the two heads look identical.

Personally I'd suggest selling the head if that won't offend your
friend, and buy an inverter. Right now you mostly have to worry about
wearing out belts and bearings. If you think R8 tooling is scarce and
expensive, wait until you need parts for that head...

That's also something to consider, thanks.

I've been more than happy with the machine's original J head, and the
only reason I'm playing around with this now is because it's (so far at
least) a zero cost option. Ideally, if I could somehow get the machine
swapped from a stepped pulley to variable speed drive without spending a
lot of money I'd be happy.

One thing to check before you do this is the condition of the
parts of the variable speed pulleys to make sure that they don't need
replacement and thus will quickly lead to problems. The things to check
a

1) The Delrin sleeve inside the sliding pulley half, so it will
slide properly on the motor spindle (and on the quill spindle as
well).

2) The key which slides in a slot in the motor's spindle, and
a similar one in the quill's spindle. This is steel with a
skin of Delrin so it slides smoothly in the keyways. it bolts
into the moving half of the pulley, IIRC.

If the latter is worn out (worn to the steel) it will start
wearing the keyway so it will not allow things to slide smoothly
while varying the speed. And this one will require replacing
the spindle of the motor -- or the rotor with the spindle.
(I've had to do this with an old machine.)

Good Luck,
DoN.

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