Eccentric Bushing Compatability

shipwright · Post by **shipwright** » Sun Feb 23, 2014 6:04 pm

I just stripped out the keyway in my control sheave. I found a complete assembly on ebay but it appears to be the old style shaft with a single long bearing on the drive end. My 510 has the newer shaft with two narrow bearings.
The SS parts site says that a new shaft will require the new eccentric bushing.

My question is does the old shaft (bearing) fit in the newer eccentric bushing?

If not I'll likely keep the shaft I have and just sub in the sheaves, or maybe the sheaves and bearings if that's do-able.

dusty · Post by **dusty** » Sun Feb 23, 2014 6:45 pm

shipwright wrote:I just stripped out the keyway in my control sheave. I found a complete assembly on ebay but it appears to be the old style shaft with a single long bearing on the drive end. My 510 has the newer shaft with two narrow bearings.
The SS parts site says that a new shaft will require the new eccentric bushing.

My question is does the old shaft (bearing) fit in the newer eccentric bushing?

If not I'll likely keep the shaft I have and just sub in the sheaves, or maybe the sheaves and bearings if that's do-able.

Yes, it fits and I see no reason why it would not work.

I bought the new shaft and I believe I retained the old shaft and eccentric. I'll double check.

Under force, the Main Table may move that much but should settle back to an original position when the force is removed.

May I suggest I repeat of the table alignment but this time, if you attempted to pivot around the rear/left trunnion bolt, this time try but pivot around a different bolt. I would suggest the right/front.

Your table should be closer to parallel than that if you suggest push the table back and to the left.

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Are you out of commission?

If so, let me know. I can shorten your wait for parts.

shipwright · Post by **shipwright** » Sun Feb 23, 2014 7:16 pm

Thanks Dusty. My guess is that SS says you need to change to the newer split type for the new two bearing shaft because the old set screw would hit between the new bearings and not retain anything. The single long bearing should have no problem however being squeezed by the split bushing.

algale · Post by **algale** » Sun Feb 23, 2014 8:17 pm

Any idea what caused the problem?

shipwright · Post by **shipwright** » Sun Feb 23, 2014 10:18 pm

Long answer: Yes, I do. Speculation of course but I think it was caused by a sticky spot on the lower (motor) shaft. A couple of years ago when I returned to Az I found the outer motor sheave stuck on the shaft. I disassembled it, cleaned it up and re-lubed it but it has always been a little sticky if I'm late with the routine oil. I think that as I increased speed that sheave may have stuck so that the spring didn't take up the slack being given by the top (control) sheaves. This in turn would leave the control sheaves a little room to start to rattle. ....yes, I ignored the rattle for a while ..... I was busy with something.
To make a long story a little shorter the steel key is harder than the aluminium sheave so now I have a very wide keyway.

Short answer: Yes, Operator error.

JPG · Post by **JPG** » Sun Feb 23, 2014 10:53 pm

Keep yer new shaft, bearings, eccentric, and idler sheave retaining clip. Use the key, idler sheave and control sheave from e-bay.(see below)

The 2 bearing setup is better than the older setup. Now would be a good time to replace those bearings if they are close to needing that.

The new eccentric will work with the older bearing, as it is split and will squeeze the bearing as the clamping screw is tightened.(the easier way;))

shipwright · Post by **shipwright** » Mon Feb 24, 2014 12:19 am

Thanks JPG, that's what I was leaning toward anyway. If the new setup is better, then that clinches it. The bearings are fine.
I just have to remember to oil the lower shaft more regularly. I got it as smooth as I could but there is still a little pitting. It's fine when lubed properly but gets sticky at that spot when I get lazy about the lubing.

billmayo · Post by **billmayo** » Mon Feb 24, 2014 9:41 am

I find the most important thing is to use a 3/4" body washer to retain the idler shaft bearing and eccentric bushing inside the headstock. The stock washer is too small once the eccentric bushing is more than half way twisted for the belt tension to prevent the idler shaft bearing from coming out of the eccentric bushing. The split eccentric bushing will work with any idler shaft bearing setup. I am finding eccentric bushings without any set screw or retaining screw in the eccentric bushing end where the idler shaft bearing had not spun in the eccentric bushing but remained fully seated. The large body washer works well for this eccentric bushing. I believe the belt tension is what keeps the idler shaft bearing from spinning in the solid eccentric bushing without a set screw. So far, I have 5 different eccentric bushings that Shopsmith has used in the Mark V headstock.

shipwright · Post by **shipwright** » Mon Feb 24, 2014 12:28 pm

Thanks Bill, Ill change the washer.

JPG · Post by **JPG** » Mon Feb 24, 2014 12:43 pm

shipwright wrote:Thanks JPG, that's what I was leaning toward anyway. If the new setup is better, then that clinches it. The bearings are fine.
I just have to remember to oil the lower shaft more regularly. I got it as smooth as I could but there is still a little pitting. It's fine when lubed properly but gets sticky at that spot when I get lazy about the lubing.

The reason I consider it 'better' is that the dual bearings are replaceable, whereas the older water pump bearing is not. That said, the older bearings last a very long time if not squeezed too much.