On Feb 4, 7:39*pm, "DoN. Nichols" wrote:
On 2010-02-04, Ignoramus25542 wrote:

The cleanup of the lathe is basically done all around, the VFD is
wired the way I want and things are cookin'.

Got something else going on...

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.

* * * * I can think a few possible causes:

1) * * *A large chip embedded in the Acme thread of the leadscrew (or
* * * * the long key groove used to power the power feed in some
* * * * machines).

2) * * *A bent leadscrew, bumping the half-nuts open.

3) * * *Badly worn half-nut threads. *(It is possible to
* * * * cast new ones in Babbit metal.)

4) * * *Missing detent spring in the half-nuts lever assembly.

5) * * *Is the interlock between the half-nut lever and the power
* * * * feed lever working properly? *It should not be possible to
* * * * engage both at the same time. *Each should lock out the other.

* * * * Good Luck,
* * * * * * * * DoN.

--
*Email: * * | Voice (all times): (703) 938-4564
* * * * (too) near Washington D.C. |http://www.d-and-d.com/dnichols/DoN.html
* * * * * *--- Black Holes are where God is dividing by zero ---


I found that a tooth brush is pretty good for cleaning the lead
screw. Just hold it against the screw at an angle. If the crap is
packed really tight in the (fine) threads a brass brush would be
better. Don't think I'd use a steel implement to run in the threads.

My olde 6" Atlas would develop a similar symptom and it turned out to
be crap collected in the threads thereof.

A good cleaning and oiling and we were good to go.

As Jon wrote above, On this lathe the whole carriage can be removed
by sliding it off the right hand end off the bed. Only had to remove
the lead screw bearing to to this.

Wolfgang