Uneven printing on vandercook sp-20

e.aubertbonn
on 20 May 11 (12:54)

Hi.
We have just found a vandercook sp-20 that has been in storage for a very long time and started to print with it. The printing pressure is clearly stronger on one side than on the other. (not the operating side, the other side.) The press is level. Is there any way we can adjust this?
Thanks.

parallel_imp
on 20 May 11 (17:52)

Well, the impression bearings could be loose on the weak side. Another possibility is that you have a broken trip spring, and one side is stuck in the up position. If you look at the rings on the side of the cylinder carriage (the near one has the handle centered in it), they should rotate a bit when the cylinder moves from print to trip to print. The cylinder is at print when it is at the feedboard, and would rotate back to trip at the end of the bed (if you put the cylinder on trip, it would rotate before it reaches the bed, and then go back to print when it returns to the feedboard).

e.aubertbonn
on 24 May 11 (19:11)

Thanks for your answers. It was indeed the trip/print mechanism that was stuck. It now prints like a charm!

parallel_imp
on 24 May 11 (23:51)

I’ll mention that another cause for a stuck print/trip mechanism is when the cheek plates are tightened fast against the carriage. That will prevent rotation of the eccentric bearings. Some SPs have shim plates for clearance, or setscrews for relief. When you remove the cheek plates, be very careful replacing them.