Lathe help please

[Everett]

I was using my lathe all day at the speed just up from center. My problem is that while turning a pen the speed dtopped to half or more. What has happened to the motor and how can i fix it. Thanks ahead of your answers. I am in the albany, troy area of new york state.

 

[monophoto]

What is the make and model of your lathe?
How old is it?
Were you stressing the lathe and forcing it to work harder than usual?
Did your lathe produce any unusual sounds?

Your too-brief description implies that your lathe has electronic speed control, but "just up from center' could also be interpreted to mean that you have a Reeves drive machine. There's a big difference.

The most obvious cause of the symptom you experienced was that you were overloading the lathe and forcing the motor to stall. But the symptom could also indicate the need for maintenance - incipient bearing failure, brushes that need to be replaced, etc. Or you could be seeing early signs of a very serious problem such as a failing speed control or excessive wear in the Reeves drive.

 

[Everett]

Sorry for the short description. It is a delta midi. It is manual change speed belt. So the speed i was using was the fourth pully from the left. No i wasnt forcing the lathe by over pushing with my tools. No there was no strange noises before it went to half or less speed. If you try to cut with it now the spinning lathe just almost stops.

 

[mecompco]

Pretty obvious suggestion, but how is the belt? I was given the same Delta Midi lathe, new but had sat unused for 20 odd years. Turned one pen fine, then the lathe slowed and would barely turn. Checked and the belt was mostly shredded. Replaced it and it's been fine.

 

[KBs Pensnmore]

Check that your pulleys are on the shafts tightly, there should be a grub screw in the pulley somewhere. It can be a common problem, especially on a new machine or even on a machine that is several years old.
Kryn

 

[jttheclockman]

The obvious things to look for are in the belt area. As mentioned check to see if the pulleys are tight and in the right place. The hold down screw may have worked loose and it is possible the pulley may have slid some or is slipping around the shaft. Also check to see if the belt is in good shape. If the pulley slipped it may have worn the edge of the belt. Make sure the belt is not slipping. I believe the motor is the counter weight as in the jet models. Make sure there is nothing under the motor to keep it from dropping where it needs to be. Start there and report back. Good luck.

 

[Everett]

Ok thank you guys. I will take a look at all of these sugestions as soon as i get home from work.

 

[Everett]

Ok so i have checked the pully tightening screws they are all tight. The motor tightening postion was tight. The belt is good. I have uploaded a video of what it is doing and the sound to my fb account. If some one can watch u can find me at Everett Seifridsberger.
Thank you.

 

[jimm1]

Check the belt tension "clamp."

 

[Wood Butcher]

What lathe are you using? Jet had some issues with the variable speed on the mini lathe and I think they have a fix for it.
WB

 

[jttheclockman]

the OP said a Delta Midi lathe non vs.

My next suggestion is to change belt settings and see if the same thing happens. If the belt is not slipping it would be rare for a motor to loose rpms as you turn unless you are putting stress on it from pushing too hard. I do not know how to access FB account.

 

[sbwertz]

Check that your pulleys are on the shafts tightly, there should be a grub screw in the pulley somewhere. It can be a common problem, especially on a new machine or even on a machine that is several years old.
Kryn

I thought the bearings were going out on my lathe when it started to squeal and lost power...The grub screw was loose.

I see you checked that already. I don't use facebook, so I can't see the video.

 

[monophoto]

Summarizing what I have see here - the motor starts OK, but stalls as soon as load is applied. The lathe in question is a fixed speed lathe using belts and pulleys to change speed (ie, not electronic speed control and no reeves drive).

The symptom is that the lathe cannot deliver torque to the workpiece. That means that one of three things:
1 The motor is unable to develop full running torque
2. There is 'torque leakage' in the mechanical linkage between the motor and the spindle.
3. There is excessive friction in the mechanical system that is increasing the load on the motor to the point where incremental loading on the spindle stalls the motor.

Everett has checked the tension on the belts, and has also confirmed that the pulleys aren't slipping. That would appear to rule out torque leakage. And the absence of noise in the bearings would rule out excessive friction. The third option is that something has changed to reduce the amount of torque that the motor can product.

What kind of motor is this? If it is a 'capacitor run' ac motor, the problem could be that the capacitor is failing. Another possibility is that there is a bad connection to the stator winding that is causing excessive voltage drop and reducing the torque that the motor can produce. I would not expect to see a dc motor absent some kind of electronic speed control, but if it is dc, then the problem could be worn brushes.

 

[smik]

I would also check voltage at your source.