[croweater (Richard)]

Some more photos Malcolm. The "unknown part" is the drive wheel that has rubber insert to act as a clutch. It is slid on polar shaft to be turned by the worm drive.After the drive wheel/ cog is on a locking clamp with rubber clutch is slid on and clamped there with a collar. When the clutch is tightened it pushes against the drive wheel to drive the polar axis. This works well as the worm and cog are left driving all the time. Hope it makes sense. Cheers Richard ps The graduated circle screwed on the face of the drive wheel is the RA setting circle