There should be a small rubber washer, about the size of a quarter, that slips over the spindle and sits on the platter. The record sits on this washer and then is held tight by the clamp. Is this there?.... I can't tell from your post. Might be the problem if it's missing. You shouldn't tighten the clamp too much... I think "snug" would be a good way to discribe it.
Chris
Chris
Chris
Chris