pork chop

JPG · Post by **JPG** » Mon Jan 05, 2009 3:49 am

Yah I got one with a triangular shaped keyway too. The key was also worn badly. It got so bad the control sheave was jumping into the next "slot" (the part where the two sheaves overlap.) This was NOT GOOD. Tended to jam things up a bit.

The IDLER sheave had NO apparent wear. The control shaft was not worn too much. Replaced control sheave and key and have been a happy camper since!:)......also lubricated it...and since!

billmayo · Post by **billmayo** » Mon Jan 05, 2009 10:12 am

I agree. The steel idler shaft does real well on wear but the control sheave can appear to wear excessively on the inside. I find the floating sheave on the motor shaft experiences the same problem. I believe that since the belt is only around about 2/3 of both sheaves at all times, it is putting pressure on the sheaves and trying to tilt them. With no oil film present, this constant rocking/pounding action will tend to beat on the inside surface of the sheaves and slowly displace the surface material. This rocking action will wear the key and key way too. I have found a few control sheaves that I can ring like a bell on the idler shaft due to excessive wear from lack of lubication.

charlese wrote:(I have not seen idler sheave/control shaft wear problems since they do not move relative to each other.)

One would think there should be no wear between the two parts since they only slide back and forth while the key absorbs the rotational forces.

However, from my own experience of not lubricating well enough, and giving the machine a lot of use, the control shaft "tube" (made of brass/bronze) actually began to change into an oval shape. The steel shaft of the idler sheave had become worn and the the key had rotated in it's key-way causing rounded edges on the key and spread and worn the sides of the key-way.

This damage was accomplished/caused during 4 years continuous use with improper lubrication.

JPG · Post by **JPG** » Mon Jan 05, 2009 11:38 am

billmayo wrote:I agree. The steel idler shaft does real well on wear but the control sheave can appear to wear excessively on the inside. I find the floating sheave on the motor shaft experiences the same problem. I believe that since the belt is only around about 2/3 of both sheaves at all times, it is putting pressure on the sheaves and trying to tilt them. With no oil film present, this constant rocking/pounding action will tend to beat on the inside surface of the sheaves and slowly displace the surface material. This rocking action will wear the key and key way too. I have found a few control sheaves that I can ring like a bell on the idler shaft due to excessive wear from lack of lubication.

Methinks that the steel shaft is much harder than the bearing material in the control sheave bore thus minimizing shaft wear.

Think your tilt theory is right on. The wear on control sheave bearing occurs mostly at the open end. The scraping of the key against the control sheave keyway slot is also greater at the 'open' end for the same reason.

Ring like a bell??(as in little contact with the shaft at the 'open' end????)

P.S. 2/3??? Ranges from 2/3 to much much less.....when 2/3 on one, much much less on the other and vice versa. Wonder which is worse (2/3 at outer rim or m m less near center)? I vote for near center....same force; less area???????

dknapp1 · Post by **dknapp1** » Mon Jan 05, 2009 7:29 pm

While fooling around again I thought I'd check out the headstock of a greenie, which was my first SS that didn't work

In any case, I was going to figure out what the problem was with that headstock too, but I found that it appeared that the control? sheave was intact with bearing and retaining clip - so my question is - have the sheaves ever changed? Can I put this sheave on my 1980ish headstock?

Pic here:
http://s185.photobucket.com/albums/x208 ... G_1714.jpg

Also in the pic you might be able to give me a hint as to the original problem - you can see on the sheave on the right, indentations in the middle of the spines that surround the sheave - like something slammed into it while it was spinning. The sheave on the left is the broken one.

Thanks!

dbk

billmayo · Post by **billmayo** » Mon Jan 05, 2009 8:08 pm

Yes, all the sheaves are similar as I can use a new one on a 1954 Mark V or vise versa. I mix and match my control and idler sheaves. I mix and match my fan and floating sheaves. There may be some very minor manufacturing differences or from wear in shafts and sheaves from different years. I mate them by insuring the inside fins/veins do not touch and are centered between the fins/veins of the opposite sheave. When closed, they sometime stick real hard so I keep looking for one that does not stick. I try to mate pairs with the least clearence (side slop) and still slide. If the key is worn/rounded, I replace it too.

The control sheave on the right had the high speed adjustment too high and ran into the speed control assembly. It makes quite a bit of noise when this happens. I would still use the right control sheave. I would recommend putting the switch wires inside the plastic clip or tieing them together so they do not touch the speed control assembly.

dknapp1 wrote:While fooling around again I thought I'd check out the headstock of a greenie, which was my first SS that didn't work ]http://s185.photobucket.com/albums/x208 ... G_1714.jpg[/url]

Also in the pic you might be able to give me a hint as to the original problem - you can see on the sheave on the right, indentations in the middle of the spines that surround the sheave - like something slammed into it while it was spinning. The sheave on the left is the broken one.

Thanks!

dbk

JPG · Post by **JPG** » Tue Jan 06, 2009 12:42 am

Bill Mayo's conclusion about sheave hitting the speed control assembly is the same as mine. This is why the 'high speed adjustment' is critical. When adjusted properly it does not have much clearance. Make sure the 'jam nut' is secure after making HS adjustment. Refer to #23!

The current part no for the control sheave fits all mark 3 versions of the ss headstock..

dknapp1 · Post by **dknapp1** » Tue Jan 06, 2009 6:22 pm

I was going to replace the sheave today, and looked at the pork chop itself - someone mentioned making sure it was lubed properly. Anyhow, I noticed some wear - pics here:
http://s185.photobucket.com/albums/x208 ... shopsmith/

Is that acceptable wear, or should I replace the pork chop and make my life easier in the long run?

Thanks!

Also, the pics are black and white, due to me feeling angst, and has nothing to do with my fooling around with the camera to take better closeups. Let me know if color would help.

dbk

dusty · Post by **dusty** » Tue Jan 06, 2009 7:10 pm

David,

I am real curious. What sort of camera do you use to get these shots, taken from inside the headstock and above the sheaves?

reible · Post by **reible** » Tue Jan 06, 2009 7:20 pm

From the looks of it I'd say a Canon Power Shot A570IS.

Ed

dusty wrote:David,

I am real curious. What sort of camera do you use to get these shots, taken from inside the headstock and above the sheaves?

dknapp1 · Post by **dknapp1** » Tue Jan 06, 2009 7:27 pm

Not sure what you mean, but maybe this pic will help orient you

http://s185.photobucket.com/albums/x208 ... G_1718.jpg

Shopsmith Forums

pork chop

Funky control sheave keyway

Control Sheave Wear

Idler shaft wear

Control Sheave

Control Sheave On Right

Pork Chop