I'm working on a Cincinnati lathe and am having trouble with the turret. It is a Duplomatic BSA 200 series 20. it needed clocked in. I got it to zero and I can grab the turret and move it 5 thou in either direction and it does'nt come back to zero. I've pulled it and tore it down and my question is what clamps the turret? It has an indexer pin but I'm fairly sure this is not the clamp function. Thanks