Helical Crayford Focuser - v2

This Focuser is adjustable, in that you can use various diameter focuser tubes (within a certain range). It can be tough to source the proper sized tube in short lengths in a cost effective way, so this design allows you to use what you can find locally. Probably the best source is PVC tubing.

A zip tie is used to close the 'petals' onto the tube. Perhaps you can use a large rubber band as well, which would be a bit better for instances where the tube isn't consistent in OD. Maybe one of th