November 15, 2011
Description
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 those silicon bracelets? A large hose clamp could also work.
Half of the bearings are also inverted. This moves the bearings into two planes, so that it only moves along one axis and doesn't tilt to the sides. In v1 this was done with steps, but I think this design is cleaner.
One revolution yields about 35 mm of travel with the standard petals, which have a 15 degree angle. The fine petals have a 5 degree angle, and I assume should be ~11.5 mm/revolution.
All the sketchup files are in the zip below. Add a comment if there's any trouble opening it.
Video: http://youtu.be/bW7UEPq3LA8
License:
GNU - LGPL
Buback
