Mark V Head Stock Rattle

[GG0452]

I have a Mark V that that i purchased new in 1983. The head stock was upgraded to a 2-bearing quill about 1986. I recently had it serviced for the first time. All the bearings and drive belt were replaced and a 2-bearing idler shaft installed. The motor runs fine and the head stock is generally quiet EXCEPT some slight rattling from the the area of the floating sheave, mostly at speeds slower than E, but is detectable at higher speeds, if you listen for it. Oiling the floating sheave does quiet the rattling but it does not go away. Supposedly the service technician checked all the parts for wear and against factory specifications. The poly-v belt was not replaced but it looks new, but i know it the the original. Is the a normal sound for the Mark V? I don't remember the rattling in the past. Also, where should the Poly-V belt be placed on the Drive Sleeve; centered or to the right of left of center? It is centered now. Thanks for any help.

[JPG]

Perhaps he rattle now occurs due to the floating sheave being well lubricated.

Rattles are almost guaranteed with the moving sheaves. Wear will increase the likelihood.

There should be three empty grooves in the quill end of the drive sleeve pulley. "Opinions" here vary, but IMO they are opinions, not fact.

Well that is simply wrong! Belt should start in the third groove leaving 2 grooves empty. Maybe second groove with later versions???????

[DLB]

I have a Mark V that that i purchased new in 1983. The head stock was upgraded to a 2-bearing quill about 1986. I recently had it serviced for the first time. All the bearings and drive belt were replaced and a 2-bearing idler shaft installed. The motor runs fine and the head stock is generally quiet EXCEPT some slight rattling from the the area of the floating sheave, mostly at speeds slower than E, but is detectable at higher speeds, if you listen for it. Oiling the floating sheave does quiet the rattling but it does not go away. Supposedly the service technician checked all the parts for wear and against factory specifications. The poly-v belt was not replaced but it looks new, but i know it the the original. Is the a normal sound for the Mark V? I don't remember the rattling in the past. Also, where should the Poly-V belt be placed on the Drive Sleeve; centered or to the right of left of center? It is centered now. Thanks for any help.

Rattling - I don't have experience with the two bearing Idler except for the similar version on the PowerPro (PP). On the PP, the Idler bearings tend to rattle when the belt tensions are not balanced. The solution on the PP is to adjust the Idler Eccentric for minimum or no bearing noise. IIWM, I'd try adjusting the Idler Eccentric a little tighter and looser and see if this has any effect on the rattle. I know that this is only in the neighborhood of the floating sheave. My second guess would be wear on the inner bore of the floating sheave itself. That's probably more consistent with the other symptoms you have described, but resolution is somewhat more expensive than adjusting the Idler. I don't know how to quantify when the wear becomes excessive but sometimes it is pretty obvious. If it is loose enough on the motor shaft to bother you, then IIWM I'd buy a new one as the mothership isn't embracing long term support for conventional headstocks and these type parts may or may not be available in the future.

- David

[GG0452]

I recently had the floating sheave replaced with a new one by a repair shop. They must not of turned the machine on after installation because when i started it up it made a real racket. I complained and the repair guy said he checked his entire inventory of floating sheaves and they were all out of spec. He sent me a "good" used one that he claimed was within specs. He also sent me his spring compressing tool and i installed the replacement part. Most, but not all the rattle went away. I will try adjusting the Poly V belt tension as I think the 2-bearing idler shaft is the same on used on the PP. Also, waiting to hear what SS says about placement of the Poly V belt. Thanks...

[JPG]

" Also, waiting to hear what SS says about placement of the Poly V belt."

Do tell us the official word when thee gets it!

[GG0452]

This is what is sent SS. I have their "Official Word" but it is not clear. Two part question. Part 1. , Looking at Shopsmith procedure "Replacement of the Poly V or Gilmer Belt ( I am installing a Poly-V Belt), reference is made to the Poly-V pulley (page 4, 2. a. and b but not shown on the diagram). Is this the grooved section of the Drive Sleave Assembly ? Part 2. Sub sections 2a. and 2b. reference headstock with a pivoting or removable name plate. With machine upgrades this is not an exact reference. Does Shopsmith mean the new 2-bearing Idler Shaft and the older single bearing Idler shaft (aka "water pump bearing")? My 1983 Idler Shaft was upgraded to the newer 2-bearing Idler Shaft so should I be following a. or b. (placement in the 2nd or 3 groove)?

[JPG]

Re: page 4,2.a. and b The pulley referred to IS the pulley on the drive sleeve shaft.

I mispoke above - two empty grooves both ends of the pulley. My memory was attuned to three. I believe that makes it centered.(13 pulley grooves, 9 belt ribs)

I be interested if anybody knows why a "C" headstock would alter the belt/pulley alignment.

[GG0452]

From SS...short and direct.

Place the belt in the second groove

Follow step 2-a for the 2-bearing idler shaft

[JPG]

Next question is, is it correct.

[GG0452]

no way for me to tell as i have only had a 2-bearing idler shaft for a couple months.