[carbidecraters]

This lathe is a basketcase...

Ok so we start it up...zero it and open and close the chuck then move it into g1 and then the spindle works just fine. Change it up to g2 and it still works fine...sounds good and run smooth. Let it sit for 10 mns and then go back to g1 and the spindle goes back and forth and wont spin. Go back to g2 and the spindle wont spin it will onyl go back and forth.

Let it sit for four hours

It then runs fine and spindle turns...worked it up to 1200rpm and then comes a dreaded crunching noise. Sounded like gears meshing badly. And then the spindle is searching and moving back and forth. If I am correct the only way the drive knows its is gear is the proximity sensor on the back that lights up when the shaft moves forward or back...this is the only sensor right? I suspect that the shift mainshaft retaining nut or bearing has gone out and the meshing gears are trying to either jump out or go back in. At this point I am not sure if we will take the entire pulley assembly apart and try to diagnose or if I will ask that the lathe be throw into the nearest lake.

[bigbobomb]

This lathe is a basketcase...

Ok so we start it up...zero it and open and close the chuck then move it into g1 and then the spindle works just fine. Change it up to g2 and it still works fine...sounds good and run smooth. Let it sit for 10 mns and then go back to g1 and the spindle goes back and forth and wont spin. Go back to g2 and the spindle wont spin it will onyl go back and forth.

Let it sit for four hours

It then runs fine and spindle turns...worked it up to 1200rpm and then comes a dreaded crunching noise. Sounded like gears meshing badly. And then the spindle is searching and moving back and forth. If I am correct the only way the drive knows its is gear is the proximity sensor on the back that lights up when the shaft moves forward or back...this is the only sensor right? I suspect that the shift mainshaft retaining nut or bearing has gone out and the meshing gears are trying to either jump out or go back in. At this point I am not sure if we will take the entire pulley assembly apart and try to diagnose or if I will ask that the lathe be throw into the nearest lake.

Where are you located at? Just for your information I do have my own service company and have over 15 years experiance with Mazak CNC machines. More then happy to assist you at your facility should you decide to bring in some help. You can private message me with your thoughts.

[carbidecraters]

MN

[chippy1]

Since you seem to have the problem when the spindle warms up, then the next thing I would try is taking a can of cool spray and cool down the top cards on the spindle unit. Power off first though. If the problem goes away temporarily, then you have isolated where the problem lyes. Once the problem comes back, then try cooling only parts of the spindle PCB's until you narrow it down to the components that are effected. Maybe a cold solder joint from vibration.

Good Luck