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"86"mv 45 spindle gears not meshing

cmccull166

Hot Rolled
Joined
Mar 29, 2013
Location
NW Pa
So I may have to put down old faithfull ..
I bought this in the early 90's its been a GREAT machine..
sits for months and runs when I need a extra spindle.BUT, today..

Its running ,Im across the shop and ALL HECK breaks loose. Ive never heard this
LOUD terrible racket before.. Rush to the machine in record time blindly stab at every red button on the controller and nothing I do helps it just keeps grinding away till finally the spindle sounds like it jambs and stops.

Well !!What the heck it doesnt owe me anything SO......

I restart it and run through the spindle low,mid,high range..

No problem so re-zero it, press go and off it goes to prep another part.I turn off the lights and go home.

Now A little back ground.. A service guy "tweaked" the shifting fork??? years ago . sometimes it had problems shifting into low range .....
recently upon start up I would have to program mid range
speed or the spindle would just oscillate till it alarmed out.
Not that any of these are a big deal ... just some background.

The grinding is a big deal any suggestions ???
 
It works now or it doesn't work? It's not clear if it worked fine when you fired it back up.

There is a counterbalance spring on the shifter rod that is always broken on these. The counterbalance spring's purpose is to keep the spindle in high range if the hydraulic unit fails while the spindle is turning.

If the hydraulics die the gears will drop out of high and try to jamb into low gear while the spindle is turning. It's about the worst sound you can possibly imagine. Sounds like what you described.

My guess is that the tech adjusted the limit switches for the shifting rod, not the shift fork.

If the hydraulic unit shuts down while the machine is on it should go into "not ready" at the control.

If the spindle speed hunts at the top end of the RPM for each range you need to put a scope on your spindle drive and adjust the duty cycle. The spindle drive manual walks you through the procedure.
 
Thanks Garwood for the info .
I have been running this the last few days .I think I will have a tech come in
and show him what you wrote ..
And yes its about the worse sound imaginable.
Thanks again Garwood
 
My MV-45 has about 1/4" of each of the gears in the headstock chewed off from this happening once every great while.

I've never had an issue with mine shifting from high to low or the other way. I think I've been into just about everything else though.

I had an idea to replace the counterbalance spring with a small cable over a pulley and a small steel slug for a weight. Just enough to balance the shift rod so it doesn't drop. If you replace the spring it just breaks in a short time. Never got around to doing it though. Food for thought.
 








 
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