Sheave Spacer missing

[jimbeaux]

I have a Shopsmith (with the small table) that I bought directly from Shopsmith about 45 years ago. So, I guess it's the Mark V model 500? I have been hearing a clicking / ticking / rubbing sound from the drive belt end of the headstock for quite a while, so I did a little research and discovered that it is most likely caused by a worn sheave spacer behind the fan sheave. I dismantled the sheave assembly only to discover that there isn't a sheave spacer.

Did Shopsmith not put a spacer in this year Mark V, or do you guys think it was just mistakenly left out during assembly? I did have quite a bit of struggle to remove the sheave in that the set screw was set so tightly that it bent the end of key.

I've ordered a replacement sheave spacer (#504205) from Shopsmith.

[chapmanruss]

jimbeaux,

Welcome to the Shopsmith Forum.

If you purchased your Shopsmith directly from the factory about 45 years ago, 1980ish, it would be what became known as the Mark V 500. That designation began for the original Table System Mark V when the Mark V 510 and 505 with the larger Table System were introduced in 1985.

The Motor Fan Sheave to Motor Spacer part number 504205 has not always been included and is not found on early Mark 5 motor shafts. Mark 5 became Mark V in 1980 as seen on the Vent Plate attached to the Belt Cover. I don't know when the Spacer became a standard part. Prior to the inclusion of the Spacer the Motor Fan Sheave was held in place only by the Set Screw. Since the introduction of the Mark 5 in 1954 the majority of the changes to the tool has been to the Headstock.

[jimbeaux]

Hi Russ, and thanks for the information. My Mark V is serial number 83461, which appears to be manufacture date of March 1981.

I'm guessing that it's okay to use the spacer on my generation Mark V even though it appears that it didn't originally come with one.

Jim

[JPG]

I am confused! The spacer was included with the Mark VII. Why not in SSInc Mark 5s?

[chapmanruss]

JPG,

Good question but I don't have an answer. In parts lists and drawings for the Mark 5 through those dated 3/74 do not have the Spacer. I have fewer consecutive manuals and drawing/parts lists after that.

jimbeaux,

You are correct that Mark V serial number 83461 was made in March 1981.

I don't know if the same Spacer can be used for all motors that have been installed in the Mark V over the years.

For the Mark VII made in the 1960's there were 2 Spacers listed apparently to go specifically with either of the 2 motor brands used in the Mark VII.

[jimbeaux]

I've read in other forum posts (in fact, posted by JPG ;-) that the spacing / gap should be 1/8" from the face of the motor end cover to the fan sheave outer edge--just a little more than enough to keep the fan sheave from rubbing against the motor end cover. I'll mic the spacer and the available space to see if it matches that spec, or maybe just install it and see where it gets me ;-) Thanks again!

[jimbeaux]

Update: the spacer arrived and is installed. The scrapping noise is gone.

In case anyone is interested, the dimensions of the spacer are: ID 0.63" (15.6mm) OD 0.75" (19mm) length 0.4" (10.3mm). After being installed the average spacing between the fan sheave outer edge and the motor end cover is 1/8" (3mm).

I suspect the following is a known thing to the community, but handy to know. During reassembly I had only snugged the fan sheave lock screw and didn't remember it until I was reinstalling the v-belt. Not wanting to dismantle most of what I had just done, I thought maybe I can use a step-bit and drill an access hole in the bottom of the lower motor housing. I laid down on my back looking up at the headstock lower shell and lo and behold, there was already an access hole! 2 minutes later the set screw was tightened, and I was on to completing the project.

[chapmanruss]

Glad to hear you were able to get it all back together.

I still can't tell when the spacer use began. The oldest manual I have found it in so far is a Mark V 500 & 510 combo manual dated 3/86. It wasn't included in the parts drawings as late as the Mark 5 Parts List and Drawings I have dated 3/74. That leaves a 12-year gap as to when Shopsmith started including it.

[JPG]

My goldie(1962) manual includes the sheave spacer pn 2095.

[chapmanruss]

Thanks JPG, I'll have to re-check my documentation again for that.