Stiff Speed Control at Lower Speeds

Greasenerd · Post by **Greasenerd** » Tue May 30, 2017 11:43 pm

Hi everyone - new to the forum. I just did a complete tear down, cleaning, lubing and repair of my 1984 headstock. I ended up replacing the quill bearing, drive sleeve bearings and drive belt. Motor bearings were fine - quiet as can be, control sheave bearing seems fine as well. Poly V belt seemed to still be in good condition. I performed the high speed adjustment. The issue I am having now is that the speed control gets very tight as I get to the lower speeds. Higher speeds are no problem - nice and smooth. I should note that I did not use grease on the quadrant assembly opting instead for some dry lube with intention of lubing often. I suppose the issue could be due to the newer belt being wider than the old one that was on there and being squeezed at the top end of the idler and control sheaves. Any other ideas as to what could cause the speed control to be tight only at the lower speeds?

JPG · Post by **JPG** » Wed May 31, 2017 12:35 am

Inadequate lubrication of the floating sheave on the motor shaft. Also possible lack of lubrication of the control sheave.

They CANNOT be over oiled.

Lack of sufficient lubrication is the leading cause of failure.

Also when adjusting towards slow, do so slowly. Give the floating sheave time to react.

P.S. a newer(wider) belt will cause the floating sheave to move further open than with the narrower belt.

Greasenerd · Post by **Greasenerd** » Wed May 31, 2017 12:40 am

Thanks JPG. I just got through cleaning and lubing, so lack of lubricating shouldn't be the cause. I will try the slower down shifting first.

JPG · Post by **JPG** » Wed May 31, 2017 1:11 am

Greasenerd wrote:Thanks JPG. I just got through cleaning and lubing, so lack of lubricating shouldn't be the cause. I will try the slower down shifting first.

Unless you oiled AND cleaned the floating shaft/sheave, all the oil in the world will not 'free it up'. You should be able to open it manually by pulling the floating sheave 'out'(yes you have to overcome that spring force).

I am guessing yours gets sticky the further open it gets.

Did you remove the sheave completely off the shaft when 'cleaning'?

P.S. Do NOT let the sheave slip and bang closed!!!!

Greasenerd · Post by **Greasenerd** » Wed May 31, 2017 9:29 am

The sheaves move quite easily. I did work the down-shifting much more slowly and it didn't tighten up near as quickly. I will chalk this up to the thicker belt for the moment. The other thing I may try is to adjust the stop to allow the belt to move a little farther out on the motor sheaves than the 1/8 to 1/16 of an inch to the rim. May let it go flush and see how the lower speed works then. Thanks!

JPG · Post by **JPG** » Wed May 31, 2017 8:27 pm

Greasenerd wrote:The sheaves move quite easily. I did work the down-shifting much more slowly and it didn't tighten up near as quickly. I will chalk this up to the thicker belt for the moment. The other thing I may try is to adjust the stop to allow the belt to move a little farther out on the motor sheaves than the 1/8 to 1/16 of an inch to the rim. May let it go flush and see how the lower speed works then. Thanks!

'High speed' stop I hope! That runs the risk of the belt dropping into the idler pulley after the belt wears(narrower and longer?). That shifts the speed down for all settings.

Greasenerd · Post by **Greasenerd** » Thu Jun 01, 2017 1:52 am

Yes - I was referring to the high speed stop

. I assume that as the belt wears over time that the same effect would happen at both high and low speeds, therefore if I adjust the spacing now it will naturally get to the 'normal' spacing as it wears. Faulty logic?

JPG · Post by **JPG** » Thu Jun 01, 2017 7:46 am

Greasenerd wrote:Yes - I was referring to the high speed stop . I assume that as the belt wears over time that the same effect would happen at both high and low speeds, therefore if I adjust the spacing now it will naturally get to the 'normal' spacing as it wears. Faulty logic?

Faulty? Maybe *

As the belt 'stretches' it will drift out further at slow.

As the belt gets narrower it moves inward, but on both pulleys. *

Net result is it runs faster.

However that takes a loooong time.

I think, that as it stretches, it also gets narrower.

The thing to avoid is the belt getting jammed in a too wide open pulley. *

Greasenerd · Post by **Greasenerd** » Thu Jun 01, 2017 9:21 pm

Good point. I was thinking about the narrowing but not the stretching. But, that would mean I really do need to allow the belt to go a little further out at the motor sheaves at high speed. Either way I've learned a lot via reading up on the manuals, forum, and teardown/ reconditioning. I don't mind doing a thorough clean out as it doesn't take me long, or at least it doesn't feel like it, and it's easy to check this while I am at it. Sawdust therapy comes in more than one form

.

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Stiff Speed Control at Lower Speeds

Stiff Speed Control at Lower Speeds

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