Power station sheave adjustments?

reluctant43 · Post by **reluctant43** » Mon May 20, 2013 2:27 pm

Just acquired a used power station for a good price ( I had an earlier post asking what to look for) and starting to look it over. Everything works perfectly except at the lowest speed the sheave that decends into the casting well as the speed is lowered just kisses the casting making a tink, tink tink noise as it just touches the edge. I put a tachometer on it and the speeds are right on the money at both ends of the speed control. The machine is 20 years old but has not seen much use judging from the excellent condition of the belts (or the belts were changed at some point). The belts seem a little loose which I understand is normal for this machine, but as I do not see any clear way to adjust the side to side motion of the sheaves I am thinking they might retract a little and miss the casting if I just tighten things up a smidge. Anybody have a similar experience with this machine? The only other problem is that while the motor runs very quietly and gets warm but does not overheat, I doubt is was ever oiled. I put 150 drops (according to the motor label) of turbine oil in the front oil cup but the back seemed full and would not take any. I am not enough of a machinist to know if this unbalanced oil need signifies a potential problem. Any thoughts on either situation? I have ordered an owners manual. I must say the forum has a lot of warnings about how noisy and rattle prone the power station is but mine is pretty darn quiet except for the tink, tink tink at low speed. I wouldn't worry too much about this except that I intend the stand mostly for the band saw will almost always be run in the low range and I am afraid it would drive me crazy...

JPG · Post by **JPG** » Mon May 20, 2013 2:37 pm

reluctant43 wrote:Just acquired a used power station for a good price ( I had an earlier post asking what to look for) and starting to look it over. Everything works perfectly except at the lowest speed the sheave that decends into the casting well as the speed is lowered just kisses the casting making a tink, tink tink noise as it just touches the edge. I put a tachometer on it and the speeds are right on the money at both ends of the speed control. The machine is 20 years old but has not seen much use judging from the excellent condition of the belts (or the belts were changed at some point). The belts seem a little loose which I understand is normal for this machine, but as I do not see any clear way to adjust the side to side motion of the sheaves I am thinking they might retract a little and miss the casting if I just tighten things up a smidge. Anybody have a similar experience with this machine? The only other problem is that while the motor runs very quietly and gets warm but does not overheat, I doubt is was ever oiled. I put 150 drops (according to the motor label) of turbine oil in the front oil cup but the back seemed full and would not take any. I am not enough of a machinist to know if this unbalanced oil need signifies a potential problem. Any thoughts on either situation? I have ordered an owners manual. I must say the forum has a lot of warnings about how noisy and rattle prone the power station is but mine is pretty darn quiet except for the tink, tink tink at low speed. I wouldn't worry too much about this except that I intend the stand mostly for the band saw will almost always be run in the low range and I am afraid it would drive me crazy...

The only thing to 'adjust' is the motor mount(drive belt tension). Lowering the motor slightly should eliminate the tink tink tink.

I be curious where the oil hole/plugs are located(facing top front rear). If the 'front' one is 'horizontal', the oil probably seeped out.

SDSSmith · Post by **SDSSmith** » Mon May 20, 2013 2:57 pm

Regarding the noise at low speed the manual troubleshooting section notes that for "metal to metal scraping at low speed" the possible cause could be "Variator is rubbing against edge of opening in base" and the solution is "Setscrew on pulley has loosened, allowing pulley to move variator against opening in stand."

reluctant43 · Post by **reluctant43** » Mon May 20, 2013 3:14 pm

JPG40504 wrote:The only thing to 'adjust' is the motor mount(drive belt tension). Lowering the motor slightly should eliminate the tink tink tink.

I be curious where the oil hole/plugs are located(facing top front rear). If the 'front' one is 'horizontal', the oil probably seeped out.

Well I should have guessed that. Yes the front cup and plug are horizontal and the rear are vertical which almost certainly explains why the rear cup remained full and the front was empty.

Thanks!

reluctant43 · Post by **reluctant43** » Mon May 20, 2013 3:18 pm

SDSSmith wrote:Regarding the noise at low speed the manual troubleshooting section notes that for "metal to metal scraping at low speed" the possible cause could be "Variator is rubbing against edge of opening in base" and the solution is "Setscrew on pulley has loosened, allowing pulley to move variator against opening in stand."

Aha! I did not notice a set screw on the pulley but I will look - this sounds like IT! Thanks! I do not have a manual yet...

JPG · Post by **JPG** » Mon May 20, 2013 3:22 pm

SDSSmith wrote:Regarding the noise at low speed the manual troubleshooting section notes that for "metal to metal scraping at low speed" the possible cause could be "Variator is rubbing against edge of opening in base" and the solution is "Setscrew on pulley has loosened, allowing pulley to move variator against opening in stand."

So Where is that 'setscrew'? My 'variator' floats on the shaft.

The positioning of the output shaft pulleyI(in/out) on the shaft can affect this. I overlooked that above.

Since you have mentioned the speed(s) are correct, moving the motor pulley towards the motor may not be the correct 'adjustment' although much easier to perform.

Now a loose set screw on the output shaft pulley could be what the manual is referring to.

Moving either the motor pulley or the output shaft pulley will alter the positioning of the variator when operating.

IIWM, I would tweak the motor shaft first. If tinks return, get inside and tweak the output shaft puller(move it 'in').

Never mind! You are already 'inside'.

reluctant43 · Post by **reluctant43** » Mon May 20, 2013 4:18 pm

[quote="JPG40504"]So Where is that 'setscrew'? My 'variator' floats on the shaft.

The positioning of the output shaft pulleyI(in/out) on the shaft can affect this. I overlooked that above.

Since you have mentioned the speed(s) are correct, moving the motor pulley towards the motor may not be the correct 'adjustment' although much easier to perform.

Now a loose set screw on the output shaft pulley could be what the manual is referring to.

Moving either the motor pulley or the output shaft pulley will alter the positioning of the variator when operating.

IIWM, I would tweak the motor shaft first. If tinks return, get inside and tweak the output shaft puller(move it 'in').

Never mind! You are already 'inside'.]

My "variator" also floats on the shaft (who invents these terms anyway) but I did find a set screw on the pulley on the motor shaft and it was loose - when there was 1/8" of exposed shaft with either a loose or a tightened set screw I got the tink, tink at low speeds - when I pushed the pulley in (toward motor) slightly so 1/4" was exposed and the set screw tightened it all went away. I imagine the exact distances will vary depending on how the motor is mounted but these were the measurements on my machine. I rechecked the speeds and while a touch faster than before (why?) they are fine.

SDSSmith · Post by **SDSSmith** » Mon May 20, 2013 4:21 pm

[quote="JPG40504"]So Where is that 'setscrew'? My 'variator' floats on the shaft.

The positioning of the output shaft pulleyI(in/out) on the shaft can affect this. I overlooked that above.

Since you have mentioned the speed(s) are correct, moving the motor pulley towards the motor may not be the correct 'adjustment' although much easier to perform.

Now a loose set screw on the output shaft pulley could be what the manual is referring to.

Moving either the motor pulley or the output shaft pulley will alter the positioning of the variator when operating.

IIWM, I would tweak the motor shaft first. If tinks return, get inside and tweak the output shaft puller(move it 'in').

Never mind! You are already 'inside'.]jpg40504, Maybe you should contact Shopsmith and offer to be their technical writer.

Though the manual did not say the variator had the set screw.

reluctant43, Glad the troubleshooting tip from the manual helped.

JPG · Post by **JPG** » Mon May 20, 2013 8:08 pm

SDSSmith wrote:jpg40504, Maybe you should contact Shopsmith and offer to be their technical writer.] Glad the troubleshooting tip from the manual helped[/B].

It made me think gooder as well.

JPG · Post by **JPG** » Mon May 20, 2013 9:09 pm

reluctant43 wrote:My "variator" also floats on the shaft (who invents these terms anyway) but I did find a set screw on the pulley on the motor shaft and it was loose - when there was 1/8" of exposed shaft with either a loose or a tightened set screw I got the tink, tink at low speeds - when I pushed the pulley in (toward motor) slightly so 1/4" was exposed and the set screw tightened it all went away. I imagine the exact distances will vary depending on how the motor is mounted but these were the measurements on my machine. I rechecked the speeds and while a touch faster than before (why?) they are fine.

This is one of those things not intuitively obvious'. It becomes apparent through much observation and gaining understanding of what happens as the drive belt(motor) is pulled down into the variator.

Two(three?) things happen. The obvious one is the motor belt rides between the sheaves at a reduced radius. The 'other' thing that happens is the variator shifts in/out along it's shaft to accommodate the belts moving up/down in the sheaves in opposing direction. As the 'inner' side of the motor belt lowers into the variator, in addition to causing the sliding center sheave to move 'outward', it causes the variator to slide inward. The motor belt tries to maintain a centered position between the sheaves. Inward/inner and outward are relative to the location within the power station. Inward is towards the motor, outwards is toward the end where the tink tink tink was occurring.

Now the belt going to the output shaft is changing as a result of the variator being raised(the motor belt is being pulled down into the variator by raising the shaft it is turning on), the output shaft belt is being 'loosened' by the reducing spacing between the variator shaft and the output shaft. Also the center sheave sliding outward puts pressure against the inner side of the output shaft belt. End result then is the output shaft belt rides at a greater radius than before.

The inverse occurs when the motor belt is slackened by lowering the variator shaft.

Now for the 'speed up caused by moving the motor pulley, and why it made the tink tink tink go away. When the motor pulley is moved 'in' on the motor shaft,(or moving the motor 'in') the motor belt continues to seek a centered position between the variator sheaves. Doing so causes the variator to shift inward, thus increasing the clearance to the frame(tink tink tink elimination). That inward shift causes a slight decrease of the belt radius since the belt is also being pulled further into the variator which causes the center sheave to move outward and the output shaft belt rides at a slightly greater radius. Pant Pant Pant!

This 'understanding' came with much pain(thinking too hard) and consternation as I ran into the same issue when I first got my power station 'used'. As I came to discover, it was assembled from parts that were acquired by an e-bay seller and assembled for sale. There were 'extra' parts and mis-assembled parts and I had little faith that the motor mount was as it should be(long screws and multiple nuts and washers). I have since come to realize that Rube Goldberg motor mount was OEM! Anyway, way too many hours was spent observing the effects of moving stuff relative to other stuff. I also spent some time thinking of a way to use an 'extra' variator(another e-bay purchase from Skip Campbell) as a speed 'alterer' on a mark 5. That is an ongoing thingey. Having that variator 'in hand' added greatly to my understanding of what what happens inside the power station.

FWIW, moving the output shaft pulley will also cause shifting the variator sliding positions. The thing to be avoided, is both belts trying to center themselves and preventing each other from being successful.(another elusive thing to understand:(). When all is well, both belts do not experience side forces when equilibrium is attained.

Sorry to be so verbose, but I have 'learned' that ss info is not always 'complete'.