Shopsmith Forums

Has anyone had an issue with the belt sander tension knob failing to hold tension? I put a new belt on and turned the knob to tension it. The button on the knob clicked out and the belt was secured in place, or so I thought. Once I turn on the motor the knob releases and rotates releasing the tension. If I hold the knob with one hand to prevent it from releasing the sander works fine but that's not an ideal way to use the machine. I removed the knob and could not find any obvious breakage it just doesn't want to lock in place. Any thoughts on what I might need to do to repair this? Also I can only get parts from second hand dealers as Shop Smith doesn't ship anything to my location.

Yes. The idler wheel has an internal torsion spring in it and comes lubricated from the factory. Two things can happen to it.

#1 It can get gunk in it. If the problem is just gunk, Nick Engler has a video on YouTube that shows how to clean and lube the guts.

#2 The more serious problem is that torsion spring can lose its "spring" over time, in which case all you can do is order a brand new idler drum assembly from Shopsmith. This is an expensive part but I would not buy it used because the condition of the internal torsion spring cannot be assessed. EDIT: I see you are in a location where you can't buy from Shopsmith. Guess you will have to buy used.

Question I have to ask is do you understand how to properly tension it? The procedure is counter intuitive. Hopefully the instructions are printed on the flat plate platen underneath the belt. The arrow can be misleading. I will look for a copy to add to this post.

Search not successful - hope someone else can provide it.

Well I see it has been done!!!!

.pdf copy of tensioning instructions are in this post from Russ Chapman.

WOW, you guys are quick at giving a link. I was still posting in the other Belt Sander thread.

Ofcalipka,

Below is the actual label they are referring to. It is a PDF you can print out on 8-1/2" x 11" self-adhesive label paper. It makes three labels. It is a replica I made for my Belt Sander restorations.
.

Thank you,

It looks like it was un-tensioned and following the procedure on the label you shared here resolved the issue.

You ain't the Lone Ranger! BTDT

Getting the tension set properly is difficult without understanding the steps.

Like JPG said, I too have been there, done that.

For anyone having trouble with the tension on the 6" Belt Sander DO follow the instructions carefully.

Seems like it could be the tension knob’s locking mechanism is stripped or just not securing as it should. You might want to make sure you clean it sometimes dust or debris entering the locker may affect the locking process. If the above tips will not do the trick you may have to change the knob or the internal spring if it is week or damaged. If you can’t get parts from Shop Smith because they do not ship to your region then consider looking for generic or compatible parts from scrap dealers or internet shops.

You may have to go back and forth adjusting the idler drum position for the right tension and then re-tensioning the spring. For belts can be different lengths and stretch from use. Your looking for the sweet spot where the belt can be little longer or shorter and tensioned by the spring while the knob will still click back in.