This is the current shaft for 1100 and 900 mounts. It can also be used as an optional "heavyweight" shaft for the Mach1 or Mach2, 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 accommodate 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.
Weight: 12.9 lb. (5.8 kg)
Length: 16.675" usable length can hold up to six 30 lb. counterweights (180 lb. total - Note: This exceeds 1100GTO recommended capacity.).
Counterweights: 5 lb. (5SCWT), 10 lb. (10SCWT), 18 lb. (18SCWT), 24 lb. (24SCWT - no longer available) and 30 lb. (30SCWT188) counterweights.
Use with these mounts: 1100, 1200, 900 (except older mounts with shaft encoders). It may also be used with the Mach2GTO or Mach1GTO if care is taken not to exceed the mount's recommended capacity. For the Mach1GTO, you must also consider that you may not be able to balance lighter telescopes when using this shaft.
Important Mount Balancing Note: Please read this document to understand the proper way to position counterweights when balancing your mount: Recommended Balanacing Techniques to Optimize Guiding