ho hum .... the plot thickens. Took off the covers again this morning to try and check the alignment - impossible

The motor pulley has a bit of flange that a long ruler can be laid on - but the pulley on the main spindle has virtually nothing protruding. Laying my 24" ruler along the motor pulley flange it's short by 6" - trying to do the same with my 1 metre rule theres no way it's going in

So when all else fails read the manual : I found a paragraph in the maintenance booklet referring to belt tension, and just maybe I've underestimated how much tension is required on this belt. They refer to a 200 Newton force depressing the belt half way along and getting 14 mm of deflection. Now 200 Newtons is far more force than I've been exerting to get about 1/2" of deflection. So just perhaps it only needs tightening - that seems an awful lot of side force on the spindle bearings

I certainly hope that the belt doesn't need changing in the future. The spindle has the drive pulley, then the belt drive for the rotary encoder, then the spindle hydraulic brake, then the hollow hydraulic cylinder for the collet closer all mounted on the end all with their associated pipes and wires - it would be a long job !
... but at the moment it's not squealing !!!!
Andrew