MARK VII Caster PLUG and dimensions

[JPG]

Just acquired an almost NIB set of casters for a Mark VII from a forum member seeking room in his shop for more useful(to him) stuff.

Inside the box was something unexpected. Four little punch circles about 0.15" thick.

Also included was an almost disintegrated instruction sheet describing what to do with them.

They are to be inserted into the piston so as to limit the penetration of the caster stem into the piston. I doubt many of those plugs survive after removal of the caster for whatever reason. They simply drop on the floor and disappear!

Is it possible that the fracturing piston problem is the result of these missing spacers? NOPE! see https://www.shopsmith.com/ss_forum/view ... 65#p271265

Without the spacer(plug) the piston rests on the caster shoulder. With the spacer, the caster CLEARS the caster shoulder by about 1/16".

I include a sketch describing this with dimensions.

Mark VII caster plug dimensioned.jpg (2.2 MiB) Viewed 9939 times

[robinson46176]

Hi JPG:
Did I miss what kind of material the thin plugs are? Metal? Cardboard / fiber?


.

[JPG]

Mild hot rolled steel. No I did not say!

They really are punch 'scrap'. The burr from the punching remains.

[chapmanruss]

So the spacer appears to be a solution to a design flaw.

[JPG]

So the spacer appears to be a solution to a design flaw.

Or the discontinuance of availablity of original design stem length.

We shall never know. Actually I think the weak link is the piston 'holder'.

I been fussed at(rightfully so) for using "almost" above in the initial post. Almost because the parts are over 40 yr old and the box was previously opened(and extra stuff put there!).

ALL the SS parts were unused!!!!!.

[robinson46176]

Seems like an acceptable solution. I am wondering if a drop of some kind of adhesive in first might prevent later loss by someone unaware of their presence?


.

[JPG]

Seems like an acceptable solution. I am wondering if a drop of some kind of adhesive in first might prevent later loss by someone unaware of their presence?


.

Especially since I believe they were scrap from some other manufacturing operation probably not related to SS.

I was thinking the same thing but fear that would make proper insertion tricky(they are not prone to laying flat in the bottom of the bore).

[rjent]

After having successfully turned 5 or 6 of the pistons on the metal lathe, I will only add that either, like you alluded to, they are not for the purpose suggested, or, they were to compensate for a change in availability of stem length, like was also mentioned.

I have just about got a full solution for casters that will be the equivalent of the large red casters being sold for the Mark X machines. A few bumps still, but just about there. I have my aluminum pistons pretty well perfected.

Kind of put on a back burner for a while while I work on other things ...

[JPG]

Me thinks a shallower bore and the objective is that clearance off the caster 'shoulder'.

I wondered how long it would take thee to discover this thread!

I have not checked the stem length of my 'previous' MVII casters(recently).

[JPG]

Me thinks a shallower bore and the objective is that clearance off the caster 'shoulder'.

I wondered how long it would take thee to discover this thread!

I have not checked the stem length of my 'previous' MVII casters(recently).

I have now! Guess what! They are 1/4" longer!(1.375)

The piston bore is essentially the same.

The floor to shoulder height is the same.

So that explains the plug.

So it ain't a solution for the fracturing pistons.