VL300 Lacking torque

[quercus]

I have an older Mechanical Variable Drive VL300 long bed. as an occasional rather than fanatical turner I have found it great, with obviously plenty of capacity- except for torque. I find that it bogs down quite quickly especially with large lumps. I occasionally hear the belt squealing a bit, but i feel that it is more the motor not having enough power. Wondering if anyone else has had similar issues and whether you think Its worth upgrading the motor to a bigger unit?

I've never really monkeyed around with the Variable drive apart from spraying some Tac5 on the belt occasionally - and never greased or adjusted anything. Does anyone recommend any particular maintenance regime?

The other option is to swap over the mechanicals to a newer Variable drive, which from what I can see would cost around 2k in parts.

[Optimark]

I'm assuming there are variable belt pulleys, if so, are you on the smallest pulley?

Unless you are in the correct speed range, your torque could be lowered, you may be on the high or maybe the mid range pulley, either of which would compromise the motor when running large material.

I would have thought that if the belt is squealing, the motor is running but the belt is slipping due to either being worn, or not tight enough.

Last year I replaced the belt on my Nova lathe due to slippage and a little bit of squealing. I couldn't find anything obvious, but once I removed the belt I noted that the ribs of the drive belt were frayed and breaking down. I assumed that the age of the belt and the workload it had endured were the problem. I am not 100% sure that was the issue, however, after replacing the belt, I have not had any squealing nor any slipping issues since.

The Vicmarc 300 I occasionally use, which is quite old and has a huge dinosaur variable unit, is very powerful; awesome machine.

Mick.

[quercus]

There are no multiple pulleys, just a constantly variable mechanical setup- beyond my powers of description. But yes, the belt may will be glazed or too loose, I will get in and drop the motor out for a look/ clean. It only runs on a 10 amp plug so I assume the motor is not huge, but is original so I can’t imagine Vic Marc would have specified a low power motor for such a big lathe


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[Treecycle]

If you are taking the motor out you should be able to check the movement of the spring loaded pulley easily. Before you release the motor, adjust the lathe speed to maximum as this will allow the motor pulley to close up as much as possible and therefore reducing the tension on the belt to the lowest you can. The motor pulley is the only part that keeps tension on the belt as you change speeds.
Just make sure the sliding half of the pulley is free to move and the spring pushes it back to the closed position without hanging up at all. There should be a bronze bush inside the pulley which slides on a shaft and it needs some lubrication between the two but make sure it doesn't get on the pulley faces.
If the belt is old and hard it will not grip on the pulleys very well either. There should be no need to apply any belt grip if the motor pulley is functioning correctly and the belt is in good condition. Check the faces of the pulleys to make sure there are no worn areas but this shouldn't happen unless the speed is kept the same over a very long period of time.
https://www.youtube.com/watch?v=O4h-Me5lSOY

[turnerted]

I used to have an old VL200 mechanical variable speed and I presume your control unit would be similar , nothing like the one in Treecycle's link , but a big box that moved up and down by a linked chain .I used to find that the belt would work loose and slip .You will find there is bolt you can loosen to move the motor . I used a little jemmy bar against the motor while I retensioned the belt .Also there are four bolts which come through the back of the cabinet supporting the speed change mechanism and these can come lose too which does'nt help.
Hope this helps .
Ted

[quercus]

Thanks for the very helpful advice. I won't be able to investigate till Friday as the lathe is up in central vic. That gives me some great starting points.

[arniew]

Thanks for the very helpful advice. I won't be able to investigate till Friday as the lathe is up in central vic. That gives me some great starting points.

I’ve never noticed a lack of torque with mine. I’m in Yarra Glen if you’re interested in comparing drive chains.


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[quercus]

I’ve never noticed a lack of torque with mine. I’m in Yarra Glen if you’re interested in comparing drive chains.


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The tension adjustments on the motor have maxed out, so I guess I am up for a new belt. Which begs the question of whether it is better doing the conversion to full electric variable
As I will have to pull the headstock apart anyway. However I suppose a belt is pretty cheap.



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