"DoN. Nichols" wrote in message
...
In article ,
Adam Smith wrote:
I had a chat with Clausing Service Center a bit earlier, and the nut is
currently $48.40, the screw and nut assembly is $266.20.
Hmm ... back when I replaced them, the nut (part # 990-069) was
$43.65, and there were two choices for the leadscrew:
Q-551 $31.26 (Screw)
or
Q-551S $94.40 (Screw Assy)
The difference is that the second one has the gear pressed onto the
shaft and pinned in place.
I got the first option, and found myself wishing that I had
gotten the second one instead, as pulling that gear from the screw, and
then pressing it onto the replacement was a bit of a pain. (The pinning
was no problem, IIRC, but the pressing bent the new leadscrew slightly.
Getting it straight again was a bit of work.
Note that the part numbers above are for the 5418, but I believe
that they apply to the 5900 series as well.
The P/N's for these parts on the 5900 are 5900-88 for the screw (with gear)
and 5900-37 for the nut according to my manual and last year's Clausing
parts list. I don't know if the parts are intergangeable or not between
5400 and 5900 series lathes, but suspect not as the same parts list has the
P/Ns you quote above. The nut was $44 even and the screws were $64.87 and
$88.67.
For pricing, a gear which I have had to buy twice, was $94.01
several years ago, and is now in the $186.00 range. They had to have
more made between my first purchase and the second, and the price
reflects the cost of production in modern times, I fear.
If you want real sticker shock, try pricing the X-axis leadscrew for the
8540 mill - $1300+, as I recall.
I'm now chewing
on
what I'm going to do, but I did want to correct my post in an earlier
thread
stating that the parts were unavailable. I must have been thinking about
another parts inquiry, there doesn't seem to be any problem getting these
(other than the price that is). $325 Canadian, ... gulp.
Check whether you can get the screw without the gear -- if you
are set up to press the gear off the old leadscrew and onto the new one.
BTW, my concern is not so much backlash, as indeterminancy in how much I'm
advancing the tool when working to a set figure. I hate wanting to take 10
thou, dialing 10 thou, and getting 7 thou off. Tricky in some materials
getting that last 3 thou off without enough there to give the tool
something
to chew on.
O.K. My Clausing had been fitted with a work-around (and the
leadscrew and nut were sufficiently worn so the backlash was about
0.070"). To the right of the cross-slide at the back was an aluminum
mount screwed to the carriage to accept a 1" travel dial indicator. On
the right side of the cross-slide near the operator was an aluminum
bracket with a hole for 1/8" drill rod, and a thumbscrew for clamping
that in position. It was arranged so the end of the drill rod would
meet the point of the dial indicator, so you could roughly zero it by
sliding and clamping the drill rod, and then fine zero it by rotating
the dial on the indicator. This is fine for work within a 1" radius
range (2" diameter).
An alternative (not cheap) would be to get one of the Shooting
Star DROs and mount it to the lathe to read off your position precisely,
independent of the accuracy of the leadscrew. It might work out to be
more economical for you than the leadscrew.
A potential problem with the Shooting Star, good as they are, is that the
resolution is 0.0005", which is doubled to 0.001" for diameter
measurements. That's probably good enough for most work, but makes it hard
to sneak up on a really tight tolerance. The dial indicator would still
work of course. For the longitudinal axis I've been finding a Trav-a-dial
really handy, especially when turning or threading to a shoulder. It's muc
easier for me to track an analog dial by eye than a digital display.
I have one, which I have not yet gotten around to installing, so
I occasionally use the dial indicator just for backup, even though my
leadscrew is in good shape at the moment.
Enjoy,
DoN.
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