Clamp causing warps?

[bobschneider]

I recently acquired a heavy record clamp. It weighs just over a pound (580 g), and has a collet which clamps onto the spindle.

I've noticed that, when I clamp down on most of my LPs, it creates a significant warp at the outer edge of the LP. This varies by LP, but most of mine seem to have at least a slight warp, while before getting the clamp I only noticed warps on a minority of my albums. The warp seems to get worse if I press down on the weight before I tighten it down, but a warp is often there even if I just set the weight down on the LP, without clamping it at all. It appears that the weight it pressing down on the label area, causing the LPs to dish a bit.

I'm using this clamp on my Technics SP-15 with a copper mat I recently bought from another AK member. The mat has a shallow indentation in the label area.

Am I doing something wrong here, or has the new mat and weight just made the existing warps in my LPs more noticeable?

Thanks!

 

[grumpy]

There may be a rubber washer missing that goes between the record and the clamp. Also you may be tightening it too much. This will cause a bowl effect.

Grumpy

 

[Shackman55]

Might try getting a thin large rubber washer, or better yet a felt ring to go under it if there is an indentation on the platter it is as grumpy said causing it to bowl.