Idler shaft moving around

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edma194
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Re: Idler shaft moving around

Post by edma194 »

A Poly-V belt is way too loose if it can shift grooves on the pulley. The pictures only show one side of the eccentric so can't tell if there would be a set screw, but not sure if that would apply to that eccentric. He can use a larger washer to hold both the eccentric and the bearing in place.

coldje, is the eccentric bushing moving also or just the bearing? If the eccentric isn't moving then the clamp is tight enough. If your eccentric isn't tapped for a screw to hold a retaining washer (doesn't look like it the picture) then try a larger washer on the top where you have one retaining the eccentric already.

I wouldn't recommend tightening the clamp, it may not tighten the eccentric at all while the slot is near the 9 o'clock position. If the eccentric can be rotated very easily within the housing perhaps the clamp does need some tightening with the eccentric slot rotated to the 6 o'clock position, but that has to be done with great care. A crack in that clamp is probably irrecoverable.
Ed from Rhode Island

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chapmanruss
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Re: Idler shaft moving around

Post by chapmanruss »

coldje,

Thanks for posting pictures. The last one tells me the Idler Shaft is protruding out beyond the eccentric which it should not. The eccentric appears to be the type that does not have the retaining screw as shown in my pictures. Eccentrics with a retaining screw also have a cut on the narrow side to allow clamping pressure to go through to the bearing from the headstock casting. Eccentrics with a set screw do not have the cut on the narrow side and the headstock casting only clamps the eccentric itself. Yours should have a set screw in the eccentric to "lock" the bearing to the eccentric. If it does not have a set screw in the eccentric it may be from the early Mark 5's which had neither a retaining screw or set screw and needs the Bearing Retainers used on the "Greenie" Mark 5 beginning in the 1950's.

In your first post you start out with
I'm rebuilding a Mark V 500 headstock following Jacob Anderson's video.
With that I assumed you were working on a 1985 or later headstock which is when the designation 500 began but Mark V 500 has unfortunately become a generic term for all Mark 5/V's with the original table system. I won't go into the history but do you know when your Mark 5/V was made? If not what is the serial number including the prefix SS if it had that. This can help us identify which eccentric your headstock has.

Answering Marc's question
Will centering the poly-v belt keep the idler shaft and bearing from pushing out of the eccentric?
No, the Idler Assembly needs to be held in place in the headstock casting by the combination of the screws/washers, the screw/washer and set screw (for those using it), or the Bearing Retainers (for early headstocks) and the cap screw and nut used on all headstocks. Proper alignment of the Poly V belt is needed to keep from adding extra force "pushing" the Idler Assembly further into or out of the headstock casting but the main problem with a misaligned belt is extra wear and more work on the motor to turn the system.
Russ

Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.
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JPG
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Re: Idler shaft moving around

Post by JPG »

Majones1 wrote: Wed Oct 27, 2021 10:47 am
JPG wrote: Wed Oct 27, 2021 7:48 am left/right??? it???

A belt too far to the rear on the drive sleeve pulley will tend to force the idler pulley to the rear. Only the idler pulley is sorta free to shift.

I am unsure of why the idler shaft is sorta free to shift taking the pulley along fer the ride.
I’m sorry, I knew that left/right might be problematic terminology, but I have seen some of you use it here in the forums, and I assumed the default way of looking at the ShopSmith from the front was an understood perspective. “It” refers to the belt. I was asking if side pressure from the idler shaft drift would cause the poly-v belt to shift left two grooves? I would expect the outer race of the idler bearing(s) to be held in place by both the eccentric and a set screw (of which the type of set screw would be dependent on the model of idler bearing(s).
However the idler shaft etc IS moving. I do not think the poly-V belt will jump grooves when reasonably tensioned. The belt will run skewed.(not recommended)

Nebulous terms like pronouns and left/right can be ambiguous when referring to pictures. ;)
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coldje
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Re: Idler shaft moving around

Post by coldje »

Russ, I did replace the eccentric bearing on my headstock because it had a crack in it. The newer (used) eccentric bearing you see, is something I just put in. I thought I could use it on this headstock. Serial# 120962

I'll take a look at that poly v belt and center it. Just to check on movement, I removed the motor. The motor shaft turns easily and now, so does the spindle assembly. Hmmm. The binding up has to have something to do with the motor belt movement.
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JPG
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Re: Idler shaft moving around

Post by JPG »

Did you snug the set screw in the bottom of the eccentric into the groove on the outer sleeve of the bearing?

P.S. oil the floating sheave on the motor shaft.
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
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JPG
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Re: Idler shaft moving around

Post by JPG »

Looking at the first pix, it seems you have the newer split eccentric so you do not have the set screw mentioned above.

You need the older version with the set screw or at least the retaining screw/washer.

Post a pix showing the entire outward facing side of the eccentric.
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╟JPG ╢
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Goldie(Bought New SN 377425)/4" jointer/6" beltsander/12" planer/stripsander/bandsaw/powerstation /Scroll saw/Jig saw /Craftsman 10" ras/Craftsman 6" thicknessplaner/ Dayton10"tablesaw(restoredfromneighborstrashpile)/ Mark VII restoration in 'progress'/ 10
E[/size](SN E3779) restoration in progress, a 510 on the back burner and a growing pile of items to be eventually returned to useful life. - aka Red Grange
DLB
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Re: Idler shaft moving around

Post by DLB »

JPG wrote: Wed Oct 27, 2021 2:17 pm Looking at the first pix, it seems you have the newer split eccentric so you do not have the set screw mentioned above.

You need the older version with the set screw or at least the retaining screw/washer.
If you are handy with a drill and tap adding the screw and washer is easy. Whatever alloy the eccentric is made from it threads really easily. But it has to be a very small diameter screw. Personal opinion, I prefer the split eccentric but until now I've never seen one without the stop screw for the bearing. The screw in question is shown above in Russ's last picture at about the 8:30 position on his eccentric.

I noticed the drive belt is riding near the outer edge of the motor sheaves. Getting back to Marc's earlier post, this suggest it needs a high speed adjustment. Normally for the fastest speed (mechanical stop) the belt would be about 1/8" from the outside edge of the sheaves. At least two possible problems with this: 1) As Marc mentioned the belt can get too deep into the Idler sheaves where it won't work normally and will bind when you try to adjust it slower. 2) I had one that when the motor sheaves closed too far there was some form of binding that prevented them from opening up under normal operation. It acted like the sheaves became stuck together, though this might not have been the actual problem. Either of these may cause the symptoms the OP is having because the control sheave will not move to a 'slower' position. IIWM I would take the drive belt off, turn the speed control a bit slower, and re-install the belt. This should cause the belt to sit in a more normal position in the motor sheaves. If this get it working, perform the high speed adjustment procedure right away to adjust the mechanical stop.

- David
coldje
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Re: Idler shaft moving around

Post by coldje »

I think it's fixed. So I decided to install the old eccentric bearing even though it has a small crack in it. I think having that pointed set screw in the old eccentric bearing really helped to keep the idler shaft from moving around. I also installed a larger washer to retain the bearing and idler shaft as advised. Squeezing the drive belt together while turning the spindle assembly helped keep everything turning smoothly while dialing the speed control to Drum Sanding for a test. Tested, she sounds just like a Shopsmith. I have a few stickers to replace and then the headstock will go back on the way tubes. This thing was a mess when I got it in VA for $300. It had been stored in the rafters of a shop for some time.
Thanks for everyone's kind help. I'll post before and after shots soon.
Jeff
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chapmanruss
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Re: Idler shaft moving around

Post by chapmanruss »

Using the larger washer to keep the eccentric bushing and Idler bearing does pretty much the same as the normal use of the 2nd screw in the eccentric itself to keep them from pushing out.

Something to remember about the Idler Shaft assembly is the forces at play in the pulley system including the motor's pulley. The spring of the motor's pulley assembly wants to close the pulley and push the belt up out of the pulley to its limit. The Pulley Assembly of the Idler Shaft Assembly with the Speed Control Assembly closes the Idler Pulley Assembly forcing the motor pulley open against the spring. If the Idler Shaft Assembly including the Eccentric Bushing is not held correctly in place than it can move back and forth in the headstock casting when trying to change speeds. The force applied from the speed control to the Idler Pulley to close it can instead push the Idler Shaft Assembly out of the headstock casting instead of opening the motor pulley which is held closed by the spring. The "relaxed" position for the speed control components is in the high speed position when the motor spring is least compressed. This is also the reason it "feels" harder to lower the speed the closer you get to slow and maximum compression of the motor pulley spring. If the resistance going to slow speed increases it is usually an indication of needed maintenance, i.e. lubricating the Pulley Sheaves of both the Motor and Idler Shaft Assembly. If changing speeds in either direction gets harder that may indicate the need for cleaning, inspecting and dry lubrication of the worm gear and the teeth of the quadrant assembly aka "porkchop". These should both be done at the regular maintenance intervals.
Russ

Mark V completely upgraded to Mark 7
Mark V 520
All SPT's & 2 Power Stations
Model 10ER S/N R64000 first one I restored on bench w/ metal ends & retractable casters.
Has Speed Changer, 4E Jointer, Jig Saw with lamp, a complete set of original accessories & much more.
Model 10E's S/N's 1076 & 1077 oldest ones I have restored. Mark 2 S/N 85959 restored. Others to be restored.
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