This Counterweight Shaft is the standard shaft for 1100GTO and all 900GTO mounts shipped after January 2007. It can also be used as an optional "heavyweight" shaft for the Mach2GTO, or even as an optional "lightweight" shaft for the 1200 or 1600 for those times that you remove the big scope and put a small instrument on the big mount.
The threads on the mount end of the shaft have a lead-in to help prevent cross threading. We machined matching female threads into the far end of the counterweight shaft, to accept the versatile 8.5" extension (M12675) so that you don't have to order a longer shaft to accomodate a larger scope. The washerless Safety Stop (M12676) is a required accessory for this counterweight shaft.
This 1.875" diameter counterweight shaft is precision-machined from solid 303 stainless steel as are all the counterweight shafts we produce. It weighs in at 12.9 lb. (5.8 kg) and its 16.675" usable length can hold up to six 30 lb. counterweights (180 lb. total - Note: This exceeds 1100GTO recommended capacity.). It is compatible with our 5 lb. (5SCWT), 10 lb. (10SCWT), 18 lb. (18SCWT), 24 lb. (24SCWT) and 30 lb. (30SCWT188) counterweights.
This shaft is recommended for: the 1100GTO, and all 900 models (HDA, QMD, SMD and GTO) that have been produced. It may also be used with the Mach2GTO if care is taken not to exceed the mount's recommended capacity.