Shopsmith Forums

If you remove the "button bearing" from a control sheave do you have a floating sheave?

Conversely, can you build a control sheave by installing a button bearing into a floating sheave?

I've never had a control sheave that had button bearing problems.

Dusty,

I know you love examining how thing work on the Shopsmith Tools. I especially like the drawings you make to show how things do work.

If I am understanding you correctly, you are asking if the Control Sheave on the Idler Pulley Assembly and the Floating Sheave on the Motor Pulley Assembly are possibly interchangeable. I am asking simply for some clarity. Will the Control Sheave work in place of the Floating Sheave if the Button Bearing is removed? I cannot actually answer that. Can a Button Bearing be added to a Floating Sheave and be used in place of a Control Sheave? Again, I cannot answer that. It has been a while since I have had a Headstock completely apart.

Here are some questions that may help in getting to the answer.

Are the Idler Shaft and the Motor Shaft the same diameter and are the keys the same size? If so they may be interchangeable.

Is the diameter of the sleeve area (as shown by the circled area in the picture below) the same diameter on both? If so the Control Sheave may be able to replace the Floating Sheave and a Floating Sheave may be able to have a Button Bearing installed on the end of it's sleeve section.

Is the sleeve section of the Control Sheave and the Floating Sheave the same length? If so they very well may be interchangeable although some modification may be needed for the Floating Sheave to have a Button Bearing installed.

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dusty wrote: Thu Aug 19, 2021 7:44 pm If you remove the "button bearing" from a control sheave do you have a floating sheave?

Conversely, can you build a control sheave by installing a button bearing into a floating sheave?

I've never had a control sheave that had button bearing problems.

IIRC they are not the same, but it has been many years since I had a button bearing problem. I'm pretty sure that the control sheave has a counter bore to accept the bearing, and this counter bore is not present on a floating sheave.

- David

The question came up while I was fine tuning some of my drawings. When I finished the two in question, they are remarkably similar. The floating sheave must accommodation the motor shaft. Therefore it has a 5/8" bore. for the motor shaft.

The Control sheave is physically similar but it has the button bearing on the end. I have not pulled the floating sheave off the motor because I am not going to subject myself to that spring unless I have. But I believe that a floating sheave plus a button bearing equals a control sheave.

This would be consistent with a lot that I have come to believe about the Shopsmith design.

Having said that....I must add: I have concluded that the Shopsmith design was done with a measurement tolerance of 1/16". The most common measure is in 1/8" increments.

The Motor Shaft being 5/8" and we know the Idler Shaft is 5/8" answers the first question of shaft diameters.

dusty wrote: Fri Aug 20, 2021 1:58 pm I have not pulled the floating sheave off the motor because I am not going to subject myself to that spring unless I have to.

I would not do that unless I had to either.

It's off to ebay in search of an unattached Fan Sheave.

I have at least two of those sitting in the parts bin. I can't do it today but I'll dig one up tomorrow. I can take measurements, or if you really want it in your hands I'll send it to you.

If you would take measurements for me that would be great, The measurements on the attached drawing would answer most of my question.

If you have a button bearing, please measure the diameter of that part of the bearing that inserts into the shaft on the sheave,
If you have floating sheaves you might have the spring too. If you do, how long is it when not suppressed?

I should have all of that, although I'm not quite sure where the spring is right now.

Ok, looked in the parts case and found two sets of control sheaves and no motor sheaves because (slap myself upside the head) they're still on the motors. Got a motor out, later on my son will help me pull the sheaves. I'm slightly disabled right now so need help with almost anything. I'll punch out the button bearing on the control shaft and get that measurement for you. There will be an outer diameter for the bearing which seats in the control shaft, and then the inner diameter that the button is press fit into.

1st measurement though: The extended spring I have is 7 1/4" long.

Note: These parts are from very old Greenies, 1953 and 1954 I think. They use Gilmer belts with timing type pulley instead of a grooved pulley.

Time is tight though, I'll try to finish this today, but there is a hurricane headed directly at my house right now. I hope we're all prepped up but sometime tomorrow we may lose power for who knows how long because National Grid runs its power lines through as many large old trees as possible.