Shopsmith Forums

The top 80% of my speed dial works fine, but it won't go slow into the bottom 20%. I did a tear down and I think I've found the problem, and pardon my lingo, as I'm not super familiar with the names.

There's a steel "toothpick" that rides on the shaft to keep the two fly wheels aligned when they open to speed the unit up, and when they close to slow them down. As you can see in the attached, I think mine is bent. Is it supposed to be like that? Whenever I take the toothpick out, I'm able to press the fly wheels tight together on the shaft, as they would be on low speed. However, when I put the toothpick in place, the fly wheels don't come all the way together. Therefore, I'm thinking my toothpick got bent.

Is this making sense to anyone out there? Do I need a new, straight toothpick? Any suggestions are welcome. I'm dying with my Shopsmith not working!

The square keystock is supposed be 'bent' as shown in your picture - however the bent end needs to be positioned down into a recess in end of the keyway(groove) on the idler shaft.

That recess is hidden under the fixed sheave of the idler pulley.

You may need to remove the fixed sheave which is retained by a small(thin) spring clip on the inner side of the sheave.

That bent end and the recess prevent the keystock from moving away from the fixed sheave.

The drawing below from October 1956 shows the parts of the Idler Shaft Assembly. The Clip JPG refers to is part number A3209 in the drawing. The Idler Shaft Assembly parts shown in the drawing remained the same until the change to the Poly V Drive in 1961. With the exception of the Eccentric the parts of the Idler Shaft Assembly were the same for all Gilmer Drive Headstocks from 1954 to early 1961. The first Mark 5's had a split Eccentric which changed to one without the split but now having a set screw (as seen in the drawing) to hold it to the Bearing which changed in July 1954. At the time it changed to the Poly V Drive the only parts that changed was the fixed Sheave to work with the Poly V Belt. Another difference was the early movable Sheave did not have a hole for lubricating it. That was also an early change but being the same part just an improvement modification.

This may be more information than you need but may help someone with a similar problem who may find this thread. Those with an early 1954 Headstock that has not been modified may have problems changing speeds but unrelated to the key being installed improperly. Poor lubrication and the Idler Shaft Assembly moving in and out of the Headstock Casting mounting point may be the problems they are having. The movable Sheave in the Motor Shaft for early Mark 5's didn't have the oil hole either. For these, oil had to be put directly on the shafts while the Sheaves were spread apart as far as possible. A more difficult way of putting oil on those shafts.

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