Mark v speed controller problem

[Majjr]

The bearing in button with clip that is connected to the sheeve on my speed controller has burned out twice with little use. I oil that bearing every time I use the machine. Can’t understand what is making it burn out. Has anyone else had this problem?

[chapmanruss]

Majjr,

Welcome to the Shopsmith Forum.

I have not had that problem. That is a sealed Bearing and should not need oiling. Over time sealed bearings will "wear" out which does happen. I have to wonder where you are getting your replacements from. Shopsmith only sells it installed in the Floating Sheave (part number 515556) of the Idler Shaft Pulley Assembly, so some owners elect to get just a replacement bearing elsewhere. This is not necessarily a bad thing, but improper installation could cause a failure. A lower quality bearing not able to handle the RPMs of the Idler Shaft could be the problem. Keep in mind the Idler shaft rotates at 1.7 times the speed of the Quill. That's over 8800 RPMs at top speed.

[edma194]

If the quadrant that pushes on the bearing is not centered and perpendicular to the shaft on the upper sheaves you'll need excessive force on the speed dial to move the sheaves. Also, the outer sheave has to slide on the shaft to change speeds, if that's not sliding smoothly it could require excessive force to change speed. Really anything that prevents the upper sheaves from opening and closing can be the problem. The problem I've seen is the roll pin that the quadrant pivots on can be loose and some users have replaced it with a nut and bolt.

[edma194]

Majjr, here is a link to Bill Mayo's headstock improvement guide: (download/file.php?id=34357)

I found that in this thread: viewtopic.php?p=314807#p314807

Look around on the forum and you should find other references to this.

[Majjr]

Thank you.