Neat.
That is a friction drive wheel.
That and lots of neat stuff can be found at Stock Drive Products.
Go to
https://sdp-si.com/eStore/ then click on Miscellaneous, then Friction drive wheels. .25 bore is a standard size. Most have a hub with set screw, to fix the wheel onto the drive shaft (encoder bearing).
Other options: Rollers, with Hub
Or, try the Pulleys, grooved, and then pursue the o-ring as a separate purchase. Least favorable, as fitting the roller (o-ring) will be a hassle.
Don't know but I'd bet McMaster Carr carry something, also.
you can set your system to accept any ratio, then? Or does the drive wheel have to be a specific diameter? Does that friction drive wheel ever slip? Timing belts would be better, I'd think, but that goes back to your issue with no axis line to use....
Just curious...for my education..since I don't (can't) build scopes from the ground up: How can you not have an Az or Alt axis? Is it a Porta-ball like scope? In which case, how can you use encoders...I guess that answers my own question. But, don't you have a central azimuth bolt as the center of rotation, or is your dob base mounted atop a plate of transfer bearings with no central az axis bolt? The pic looks like that's the alt axis there. You can find the precise center of the alt or az axis of rotation of any dob, even those lacking an obvious axis centerline, using some trig. There is this little dobsonian 'trig for dummies' (Hmmmm...I resemble that remark) powerpoint file out there, if anyone is interested...in how to zero onto the exact axis of rotation of your dob....helps when struggling to precisely align the alt encoder (the harder one, usually) to the exact center of the axis of alt rotation.
EDIT: Hey, just saw your scope on the articles page. neat. you can fit a conventional alt encoder to that, but it'd need a special bracket...kinda like how the Obsession 18" UC accepts encoders. But best regards however you do it, very nice set-up. I esp like the low profile and ability to avoid ladders with that design...wish I could drill a hole without hemorrhaging and make something like that....
Scott
Quote:
Originally Posted by tnott
I want to use this part (see attachment) to fix an encoder to so my scope can sense directions for a goto system for my Tridob. http://www.iceinspace.com.au/index.p...63,324,0,0,1,0
The conventional way of attaching the encoders to the ALT/AZ pivot points would not work for my scope as there is none. So this roller would run along the AZ bearings and ground ring instead.
It is a roller with an O ring on its circumference, a .25" hole in the middle and a grub screw to fix the encoder shaft.
Anyone know where I can find one?
Tim. |