PDA

View Full Version : Lathe does not spin easily



Tiger
22nd December 2011, 11:21 PM
My WL18 or MC900 lathe has developed an annoying habit of not spinning backwards as it used to. What happens is that I spin the handwheel in reverse and it turns a few revolutions and then it stops and it needs to be forced to keep turning, it will turn a few revolutions and then stop again. I had a look inside, lubed it, tightened everything and it still happens, I can't figure out why. Other thing I noticed is that when I reduce the speed down from a higher speed to a lower speed it is a smooth transition until I get to the lower speeds (2,3 and 4) where I feel greater resistance and there is a bit of a clunking noise but I can't work out where it's coming from. Now I don't need to spin it back often but it is helpful when taking off chucks or reverse sanding plates/bowls so if anyone has any suggestions as to what it might be I'd be appreciative.

RETIRED
23rd December 2011, 08:20 AM
Possibly the belt is binding in the pulleys.

vk4
23rd December 2011, 08:56 AM
A couple of questions,

! how old is the Lathe,?
2 how much work has IT done?
3 have you put on a new Belt?
4 can you see any wear grooves in the drive plates?

Depending on the amount of wear , these are a brush motor and brushes wear and with the movement in the holders, can wear out of square, this could be the issue,

Groves in the drive plates may have an effect
I found that the original belt was very soft and self destructed and the rubber melted

at lower speeds I find that the belt does flap / vibrate and causes noise.

Jeff

Tiger
23rd December 2011, 09:59 AM
Thanks guys, the belt is not the original and I bought it 6 months ago. There is no trace of fraying or deterioration. The lathe is about 5 years old, done probably a moderate amount of work at best. Not sure about the drive plates.

if the belt binding is the cause, is there a fix?

Woodturnerjosh
23rd December 2011, 11:42 AM
Can you remove the belt and then spin the lathe spindle and motor shaft individual? Just to rule out any bearing problems

Tiger
23rd December 2011, 12:02 PM
Hi Josh,

Both spin freely.

vk4
23rd December 2011, 07:09 PM
There is a possibility that the brushes are catching on the commutator when you turn the lathe backwards,

with the belt off the drive pulleys, turn the motor backwards , if you feel the shaft catching as youturn it, then the brushes are the cause, .

the brushes wear as the motor runs, and the trailing edge tends to be slightly longer than the leading edge, when the motor turns backwards, the longer edge catches in the separations, between the segments on the commutator,

Just a possibility.

jeff

Tiger
23rd December 2011, 07:55 PM
Jeff, motor spins freely backwards when belt is off.

RETIRED
23rd December 2011, 08:22 PM
Occasionally the belt will ride up the "V" of the pulleys and lightly "grab".

This is generally caused by the belt getting sticky from belt grip, WD40 or something dissolving the outer casing of the belt.

The only way to fix it is to put a new belt on or you could try washing it with metho.

vk4
23rd December 2011, 09:42 PM
Ok, then as , said look at the belt.

Jeff