VPI 16.5 clamp

There could possibly be other causes, if you are regularly experiencing slippage.

Going by memory, I'm thinking that the Spindle is only threaded so far on the shaft, One could possibly shim the Platter on the Platter-Motor Arbor, thus in effect raising the Platter on the Spindle.

Or one could swap the stock Cork Mat, and replace with a thicker Neoprene Mat. Neoprene sheet They can be gotten in 12x12 size from places like McMaster-Carr. Suitable Shore A Hardness, would be between 40-60.

With the stock Cork Mat, I on occasion would get slippage, if I didn't firmly crank down the knob tightly, but since changing to the Neoprene Mat, I never have that problem anymore.

The big metal clamps might look cool, but there's always the potential of accidently dropping it upon the record. There's less likely damage if this occurs with the little Nylon Nut.

The Rubber Mat, IMO killed two birds with one stone, less liklihood of slippage, and a Mat that is much easier to keep clean, and is non-porous. Mark

I buy the idea of a clamp covering the label, Chadnliz makes sense there. But I find it is virtually impossible to induce slippage with the stock knob snugged down. I think the amount of pressure required to make it slip would more likely stop the drive motor first....
I would never put that much pressure to cleaning to begin with. I have inadvertantly cleaned records forgetting to put the clamp on, and no slippage noted.

Wilson
Make sure the flat surface of the clamp is up this should solve the problem. When the other side is up the clamp doesn't hold some records tight.

Another possible cause of slippage, or maybe a better term could be called siezing.

The Vacuum Wand could possibly be out of vertical adjustment. There is a Collar on the vacuum wand assembly which is adjustable in height, and held in place with an allen set screw.

To adjust, remove Vacuum Wand Assembly, remove Coil Spring.
Now, with a Record on the Platter, swing the Vacuum Wand over on the Record. The collar should be adjusted that the Wand just contacts the record surface. If not, loosen Allen Set Screw on Collar, raise, or lower Collar on the Tube, and tighten Setscrew. Mark

are you saying an out-of-alignment wand would slip the record??

BTW VPI has a new Delrin wand now, lifetime guarantee, no cracking.