Shopsmith Forums

I noticed when oiling my machine that the shaft holding the top sheave runs into the speed control is that normal?

Are you referring to the point of contact indicated by the arrow in the picture below?

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If so that is normal and how the speed is controlled. If not can you post a picture of what you are referring to.

That's it Russ thanks just concerned

The Headstock pictured is pre-restoration but shows how it does look. As you turn the Speed Dial on the front of the Headstock the the worm gear moves the Quadrant Assembly aka "Pork Chop" back and forth which opens and closes the sheave of the Idler Pulley Assembly. The Pulley Assembly on the motor having the spring keeps the tension on the belt as each pulley opens and closes and does so opposite of the other. I hope that explanation is clear and not clear as mud.

Clear enough explanation. You need to understand how split sheaves (adjustable pulleys) work in the first place to understand any explanation of this. This video of a mechanism very similar to the Shopsmith illustrates how the effective pitch diameter of the pulleys changes as the two halves of the pulley move closer or further apart.