Hi guys,
I'm still in the process of properly setting up my PM-1236 but I suspect I have something wrong with my motor.
I noticed the machine would run quite loud and has some strong vibrations. I machined a titanium bead that came out as you see below : huge pattern is transfered to the finish.
I proceeded to check the spindle bearing preload :
- I did the "one finger spin" test, I get about 1 turn of free spining, that's supposed to be right. The chuck is not that free to spin.
- I chucked a 40mm rod in the 3-jaw chuck, grabbed with both hands that bar 400mm away from the chuck. DI positionned above the centerline, tip on the spindle cam lock area. Vertically I get about 0.0003" in the down direction; a little less around 0.0002 up. That makes sense, as it is easier for me tu push down than pull up. So 0.0005" overall. Not sure how much is acceptable but doesn't sound that much.
So I rulled out a sloppy spindle.
I then removed the belts and ran the motor alone. Left the sheave on. This is what I found :
- the noise and vibration is mostly still here, so the issue is narrowed at the motor+sheave level
- by hand, it is very easy to turn, no noticeable grit feeling, smooth (but not entirely silent ?? maybe normal, I speculate I hear the balls running in the bearing)
- when powered on, the loud humming is back along with the vibration
- I feel vibration on the motor body itself. The lathe yes but not that much. The stand, a lot. The stand acts like a resonator of some kind.
- as soon as I stop the motor power, the humming and the vibration stops eventhough it is still spinning fast. Then the motor continue to turn freely, for about 5-10 seconds. During that time, I only hear what I think is the bearings running, but the machine is silent otherwise and vibration free.
conclusion : the issue is at the motor level and only there when the motor is powered on. That pretty much rules out a defective bearing or an imbalanced rotor.
Here is a video of the sound.
Did any of you have had that kind of issue ? What is the fix ? I have a metric machine in 220V, could it be related ?
I speculate the issue is electrical but I do not know that for a fact.
Any advise welcome !
Thanks !
I'm still in the process of properly setting up my PM-1236 but I suspect I have something wrong with my motor.
I noticed the machine would run quite loud and has some strong vibrations. I machined a titanium bead that came out as you see below : huge pattern is transfered to the finish.
I proceeded to check the spindle bearing preload :
- I did the "one finger spin" test, I get about 1 turn of free spining, that's supposed to be right. The chuck is not that free to spin.
- I chucked a 40mm rod in the 3-jaw chuck, grabbed with both hands that bar 400mm away from the chuck. DI positionned above the centerline, tip on the spindle cam lock area. Vertically I get about 0.0003" in the down direction; a little less around 0.0002 up. That makes sense, as it is easier for me tu push down than pull up. So 0.0005" overall. Not sure how much is acceptable but doesn't sound that much.
So I rulled out a sloppy spindle.
I then removed the belts and ran the motor alone. Left the sheave on. This is what I found :
- the noise and vibration is mostly still here, so the issue is narrowed at the motor+sheave level
- by hand, it is very easy to turn, no noticeable grit feeling, smooth (but not entirely silent ?? maybe normal, I speculate I hear the balls running in the bearing)
- when powered on, the loud humming is back along with the vibration
- I feel vibration on the motor body itself. The lathe yes but not that much. The stand, a lot. The stand acts like a resonator of some kind.
- as soon as I stop the motor power, the humming and the vibration stops eventhough it is still spinning fast. Then the motor continue to turn freely, for about 5-10 seconds. During that time, I only hear what I think is the bearings running, but the machine is silent otherwise and vibration free.
conclusion : the issue is at the motor level and only there when the motor is powered on. That pretty much rules out a defective bearing or an imbalanced rotor.
Here is a video of the sound.
Did any of you have had that kind of issue ? What is the fix ? I have a metric machine in 220V, could it be related ?
I speculate the issue is electrical but I do not know that for a fact.
Any advise welcome !
Thanks !