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thumbsucker
16th April 2015, 01:35 AM
I have access to a basic wood lathe at my local community centre, it is a MC900 lathe.

The lathe has a problem - If you place a spindle between the centres, then turn on the lathe 50% of the time the motor turns on and the drive centre spins just fine. However the remaining time the motor makes a sound as if it is turning over however the head stock drive centre does not rotate. If you manually spin the spindle by hand to give it some momentum the lathe slowly picks up speed and starts to run.

The lathe also is temperamental when turning it on sometime it will just not turn on. The motor will not start, I have to turn it of and try the ON button again.

The lathe also has developed a rattle sound like something is bouncing around.

Any ideas about what could be wrong and how it can be fixed.

jay h
16th April 2015, 08:15 AM
Hi Thumbsucker, sounds to me like the drive belt is slipping at best, probably needs replacing and maybe a little TLC on pulleys and shafts. Have a look. Jay

Brett Hammond
16th April 2015, 08:18 AM
I'm not familiar with the lathe but it sounds like the run / start capacitor has gone. Not sure what the rattle would be but I would say that it is associated with the other problem.

Brett

thumbsucker
16th April 2015, 09:50 AM
I will have a look at the two suggestions and get back to you next week.

BobL
16th April 2015, 10:39 AM
The lathe has a problem - If you place a spindle between the centres, then turn on the lathe 50% of the time the motor turns on and the drive centre spins just fine. However the remaining time the motor makes a sound as if it is turning over however the head stock drive centre does not rotate. If you manually spin the spindle by hand to give it some momentum the lathe slowly picks up speed and starts to run.

As BretHt suggested that sounds like the start capacitor is on its way out.

To fully test this removed the belt from the motor and carefully turn it on and see if the motor starts by rotating the motor pulley.

A jay says also test the amount of slippage on the belt.

pommyphil
16th April 2015, 11:48 AM
MC 900 would have a Reeves pulley variable speed, notorious for problems, sticking, worn pulleys, etc.

Pull the cover off and check the spindle drive pulley. Phil.

elderly
16th April 2015, 04:03 PM
Notorious for capacitor problems usually caused by not starting at lowest speed. They are just a few dollars on eBay.
Cheers Frank.

issatree
17th April 2015, 02:02 AM
Hi Thumbsucker,
Try giving the switch a good blow out with some air, & see if the Grub Screws are tight on the Axle.
While you are at it, check for any odd bits of Allum. sticking out on the Cone Drives, as there is not much TLC on that Lathe, & could cut the belt out.

thumbsucker
23rd April 2015, 10:28 AM
Hi guys - excuse me but I am not particularly knowledge when it comes to machines.

Last night I had a look into the head stock.

Were exactly is the start capacitor? I assume its in the motor and I need to pull the motor apart?


Notorious for capacitor problems usually caused by not starting at lowest speed. They are just a few dollars on eBay.
Cheers Frank.

Does this mean I need to turn the lathe to a lower speed before I turn it off so I can start at a lower speed when I turn it on?

I had a look at the belt, at low speed it is loose but as you increase the speed it tensions up in the spindle drive pulley.

joe greiner
23rd April 2015, 03:07 PM
Hi guys - excuse me but I am not particularly knowledge when it comes to machines.

Last night I had a look into the head stock.

Were exactly is the start capacitor? I assume its in the motor and I need to pull the motor apart?



Does this mean I need to turn the lathe to a lower speed before I turn it off so I can start at a lower speed when I turn it on?

I had a look at the belt, at low speed it is loose but as you increase the speed it tensions up in the spindle drive pulley.

The capacitor is in the small half-barrel on top of the motor. Should be two small screws attaching it to the motor.

If the belt is loose at low speed, the motor pulley half of the Reeves drive probably isn't moving smoothly along the motor shaft. And maybe the spindle shaft half too. Lubricate these generously and exercise the speed range several times to achieve full range. This is a good habit to acquire each time you use the lathe anyway (the speed range).

The main reason to always start at the lowest speed, and to return to lowest speed at completion, is to avoid starting a severely out-of-balance workpiece at high speed, with unpleasant results.

Cheers,
Joe

elderly
23rd April 2015, 03:48 PM
https://www.youtube.com/watch?v=AxPcP1FFszs Hi Thumbsucker,
Take a look here.
Cheers Frank.