[eartaker]

My lathe has 6 speed settings. 125, 210, 420, 620, 1000, and 2000 RPM. I have never needed to or have ran the Lathe at 2000RPM but I wanted to test out my new tachometer.

When the spindle speeds up it gets to about 1600RPM and sounds like there is some vibration and it will not get up to 2000. If I flip the switch and run the spindle in reverse it gets up to 2000 with no problems and there is no chattering sound... any idea what the issue is?

[TheSteamshipCo.]

I believe that I have read that the motor has an internal brake. Could the brake have something loose that drags when the motor is turning in one direction but not in the other? Is the same thing happening with the gear change banjo disengaged? Seems like if there were a problem in the headstock bearings it would have already shown itself when the lathe was being used, but I could be wrong.

The Steamship Co.

[eartaker]

The motor doesn't have a break. it was happening with the banjo engaged and disengaged. Its odd I ran it at 1000rpm for a minute and then bumped up to 2000RPM and now the problem is gone. I have used it almost every day for the past 6 months.. might be time to do some service on the stock bearings.

[H.A.S.]

My lathe has 6 speed settings. 125, 210, 420, 620, 1000, and 2000 RPM. I have never needed to or have ran the Lathe at 2000RPM but I wanted to test out my new tachometer.

When the spindle speeds up it gets to about 1600RPM and sounds like there is some vibration and it will not get up to 2000. If I flip the switch and run the spindle in reverse it gets up to 2000 with no problems and there is no chattering sound... any idea what the issue is?

Not familiar with that particular machine. From your description, I would guess it's harmonics. Lathe level? Bolted down? Most all machines do not have exact RPMs. 1600 RPMs may actually be 1550-1650, and so on.

Could be harmonics at a certain range of speeds. Could be the belt/belts.

How close do the RPMs match your tach?

[eartaker]

Lathe is level and bolted down. your right on the non-exact RPM but the problem occurs when the spindle reaches 1650 rpm.

[Al_The_Man]

If this is the original split phase AC motor then off load there should be no difference in performance/rpm in either direction, have you listened to the motor with no belt attached?
Any difference?
Al.

[eartaker]

Al,

it is the original motor and has no issues when there is no belt. I will upgrade the motor soon but if I let it run at 1000rpm for a minute it has no issues with 2000rpm.