[Collins] 75A-4 Dial Spline Lock Nuts

[Dr. Gerald N. Johnson]

On Tue, 2006-06-27 at 07:49 -0400, Jim Walker wrote:
> Still working on the 75A-4.  I encountered a problem I have never had
> before and really need some experience.  I set the end points on the PTO
> but went to center the dial but cannot get the spline lock nuts loose.
> I have the XCELITE 99 spline set.  The set screws take the #99-62 pieces
> and the inside of the lock screws are in good condition.  I have removed
> the front panel for cleaning and have good access.  To date I have
> managed to twist the spline wrench into a noodle.  I even shortened it
> with a cut off wheel to increase the torque.  I've tried ACETONE.  I
> haven't tried heat as I can't get my solder gun down to the shaft and am
> afraid I'll damage the dial.  
> 
>  
> 
> To date there is no damage but no movement (n pun intended) on this
> problem.  I really need some suggestions.
> 
>  
> 
> Jim 
> 
> KZ5AW
> 
Heat may work. Watch out for acetone near the dial it can be as
destructive as a slipped soldering iron. Maybe heat the side of the
spline wrench.

What color is the locking stuff on the screws? Some was stronger than
the screws. Acetone may work given time to soak in. The real locking is
in the threads.

It may not be possible to loosen the dial setscrews. You may have to
compromise between dial centering and end point adjustment. Maybe you
can rotate the PTO in its linkage.
-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer