DIY Record Clamp
There are a number of different record clamping devices on the market, some of which rely on mass, and others that physically clamp the record onto the platter.

High mass record weights are popular on unsprung turntables, but the additional mass can affect the balance of those with softly sprung suspension such as the Linn LP12, Pink Triangle etc
Screw-down clamps have been used successfully by Ariston and Michell but the requirement for the spindle to have a threaded portion makes these suitable for original fitment only.

Another type, the collet style clamp, is used by Michell in their universal record clamp. This lightweight Delrin design fits standard size, unthreaded spindles and uses a collet to grip the spindle when the upper portion is turned, offering rigid coupling of the record to the platter.
The design offered for consideration here is a DIY mass type (exact weight dependent on the material used for the main body) with integral collet to grip the spindle. This should offer the benefits of both the mass type clamp and the rigid coupling of the collet type. The nut and body should be machined from brass, or you could also use an Austenitic (non-magnetic) stainless steel for the body.
DIY Collet Style Record Clamp Drawings © LPSpinner Jan 2007
Discuss the DIY Clamp in the Forum