[mconwell]

I have an older Okuma LB10, (1980's) with an OSP5000 control. I am having trouble drilling a plastic part running 750rpm using M42 in the program. The spindle boggs down and even stops when I first start running in the mornings. I decided to switch to the low range but when I substituted M41 for M42 in the program the spindle does not start up, it just oscillates back and forth instead of running in the cw direction. Anybody have any suggestions as to what Im doing wrong????

[cncts11]

Can't remember for sure on the LB10, but on the LB15, there is a shifter for low to high gear. The oscillation you describe sounds like it is trying to mesh the gears as it shifts. If that is what you have, most likely the shift rod isn't moving, which is typically caused by one of the following: 1) the relay for M41 isn't sending voltage to the respective solenoid coil, 2) the contacts on the relay for M42 is stuck to where it is still sending the voltage to its respective coil on the solenoid (even though the NC has turned off the signal to this relay) or 3) the solenoid to shift the transfer rod is bad, gummed up, bad coils, etc.There are other possibilities, such as the shifter rod is jammed/stuck, but not as likely.

[mconwell]

Thank you for the reply, that makes perfect sense. Ill look into it.

[underthetire]

An lb10 should drill plastic without issue in high range at that rpm. (unless it's some giant drill). I'm betting the spindle belts are shot/loose and once they warm up a bit are working better. Check the load meter, if it's not pegging when it slowes/stalls, it's probably the belts.

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[mconwell]

Thanks, I was wondering about that but couldnt see any evidence of the belts slipping after I removed the end cover. I will do a little more investigating and see if a new set of belts is in order. Thanks again.