Poly V belt replacement

[dusty]

Your eccentric bushing looks exactly like mine with the single exception that your does not have the screw and washer.

Your machine (555510) is a different vintage than mine (555540). Mine is a year newer. I would suggest a design change to add the screw and washer was done to resolve minor complaints from the field.

20190328_125630.jpg (1.19 MiB) Viewed 13896 times

[dusty]

I may not be following this discussion closely enough but.....

If you have an eccentric bushing that has a continuous slit as shown above (right side) but has no screw and washer...you have no means whereby you can prevent the idler shaft assembly from migrating out of the headstock except the bolt and nut that secures the eccentric. Be careful here. Others have been known to tighten that bolt too far and then breaking the tab off of the headstock casting. This means new casting.

The slit allows for the eccentric to slide over the bearing(s) with a bit more clearance than the other eccentric bushing.

For clarification (mine), does your idler shaft have this sort of bearing. I suspect not.

20190328_140933.jpg (1.3 MiB) Viewed 13893 times

[roneg]

No, dusty mine does not have what appears to be a double bearing, with a spacer set-up. What I must gather but has not really been said is;

1. There is a bushing design that employs a threaded hole that a bolt inserts into the end bushing itself.

2,. There is another design that employs a threaded hole and set screw in the middle of the bushing that attaches the bearing to the bushing by means of a groove in the bearing, that in turn is secured by the threaded bolt that screws into the headstock with a washer.


3. and this is my design..There is a inferior design (thus the two previous designs)that employs a continuous slit through the eccentric bushing thereby allowing a clamping effect by the tightening of the Allen bolt, and nut in the headstock. BTW this is the one no one can give a ft. pound or inch pound measurement only just to keep reintegrating "don't over tighten"! or, "I usually only tighten until the split lock washer flattens"
Is it just me or am I missing something here? Is that for the bushings that rely on other means of stability? What if that is not tight enough? what if the idler shaft is slipping? Like in my case. Do I tighten more? how mush more?

Which brings me to my unanswered question;"So..it has occurred to me the question. Why did not SS just provide a larger washer on the eccentric bushing to cover the bearing also? wouldn't that stop the bearing "creep" I'm experiencing"?
So far all I've seen , and heard in this post is showing, and talking about a eccentric bushing , and bearing configuration that employs some sort of set screw. Mine clearly does not. Am I to understand my machine is unique?, or assembled wrong..poorly. wrong parts..or none of these just my ignorance on these things?

[dusty]

The eccentric with the long slit that has no screw and washer (yours) is something I have never seen. I don't know this but I suspect that this eccentric needs to either be replaced or a hole drilled and threaded for a screw and washer.

The washer could be enlarged but if too large it might apply pressure that would prevent the bearing from turning freely. Note in the images I posted, the washer barely covers the outer race.

Without the double bearing, you have the same assembly I had until I replaced it due to the bearing not turning freely. The bearing is frequently referred to as a water pump bearings. That bearing has a groove ino which a set screw fits. That set screw prevents the eccentric from slipping on and off the water pump bearing (which is what yours appears to be doing.

I am inclined to say that your setup has the wrong eccentric bushing. That eccentric bushing came into being when the double bearing setup (which you don't have) came into being.

Your method for tightning the bolt is only until the split washer flattens is what has been advertised for years. It can't be said too frequently - don't over do it!

[thunderbirdbat]

The eccentric out of the early model Greenie (without clutch) I have looks just like the one roneg has.

https://www.shopsmith.com/ss_forum/main ... 6-s10.html

[reible]

Here is the service note on the subject:

https://www.shopsmith.com/ownersite/cat ... r_note.htm

I don't think the part you have is the right one, more then likely replaced at some point as your machine is too early for that version or to late for it.

If yours is missing the hole for the screw it was not made right and shopsmith should replace it for you or it is an earlier version which will require you to modify it or buy a new one. But again I don't think be might the right part for your machine and finding an older/new style might be what you have to do.... one the right vintage for your machine.

Or

Replace the old bearings/shaft and get all matching parts including a new eccentric, a little more costly but also the safe path.

Tightening instructions provided are there to help you.

Rather then fighting it just use the "tighten to flatten the lock washer", that is a tried and true method. If you mess up remember you will need a whole lot more, a new/used case as repair as it is rare for that mistake to be repairable.

Any reason the images are so small? Pretty hard to see them that way.

Ed

[roneg]

Thank you thindrbirdbat for the link! Makes everything perfectly clear now. I have the wrong eccentric bushing. I have the one for the grennie for sure maybe others. That style used the c shaped clip to retain the shaft so it was not necessary to tighten the Allen bolt so tight as to try and retain the shaft by this means alone. The others use the set screw configuration again not releying on the Allen bolt alone. I can't say about the other design dusty posted. Mine is having to rely on that bolt alone...not good! And it is not working.

Thank you reliable for that input and link also very informative. Even though addressing the new and old..not the very old like the one I have! I agree wrong part how it ended up on my machine can't begin to guess.

[roneg]

For the record JPG & dusty. I was wrong my idlershaft bearing does have a groove. I bit the bullet and took it back apart.

[JPG]

This has come to where it is beginning to make sense. It is possible that your 'split' eccentric is from a very old Greenie like Brenda's. That design did not require the set screw since the clip(s) that mounted on the bolt that 'squeezes' the eccentric had 'fingers' that prevented both the eccentric AND the bearing from creeping out.(look at Brenda's pix) That/those clips also prevented the eccentric from creeping INTO the headstock(shorter fingers).

So yes you need an eccentric with the setscrew and a cone point set screw.

This has been an education for me(I forgot about Brenda's Greenie). I now believe there were indeed three versions of the eccentric and bearing retention.

Back when Brenda posted her Greenie, I assumed the eccentric was the new version incorrectly used on it. I now suspect it was OEM.

If you cannot obtain the correct eccentric from the mother ship, I think one of us can 'discover' one.

[roneg]

This might make even better sense JP. When I go to SS to look for the bushing..It shows my bushing part 103 on the parts explode. Then when I click on the part, it opens the part order window with the actual Part number 515616, and no mention of a set screw anywhere..in the middle, in the end or at all. I just might need to look elsewhere.