On 2010-02-04, Ed Huntress wrote:
"Lloyd E. Sponenburgh" lloydspinsidemindspring.com wrote in message
.70...
Joseph Gwinn fired this volley in news:joegwinn-
:
In article ,
Ignoramus25542 wrote:
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If I try threading, the half nuts would not stay engaged, they lose
this engamenent in a second or so. If I hold the engagement lever,
they they do stay engaged, but I feel the lever kind of bumping.
What would be the typical cause of this?
Wear and/or maladjustment. How much backlash does the closed half-nut
have? (This ordinarily does not matter unless one is making very
accurate and long screw threads, but is used to gauge wear.)
Joe Gwinn
Iggy, odds are you'll find almost no thread at all in the half-nuts. As
they become severely worn, the will tend to "hop" out of engagement.
There's only one solution -- replace them; if you're really in a pinch,
you can re-make the parts, but I'd look for replacements first.
LLoyd
And one additional point: If it does come down to making the replacements,
and you have to make them on the same lathe, MAKE THEM NOW! Once the
half-nuts won't hold engagement at all, you're screwed.
A few points of note.
1) New half nuts are $100 from Clausing (and I think they include a
new slotted circle for engaging them)
2) I have an extra pair of worn half nuts that came with the lathe
3) I think that you guys are right, I will try to take off the
carriage and apron and look at half nuts. Taking that stuff off will
be beneficial in other ways, such as cleaning the sliding surface,
etc.