A new design, the R&P Crayford.
Posted 30 December 2013 - 05:26 AM
Posted 30 December 2013 - 05:28 AM
Posted 30 December 2013 - 09:38 AM
Posted 30 December 2013 - 10:04 AM
 Realized I wrote ring and pinion instead of rack and pinion - got my head in the car world. Sorry.
Posted 30 December 2013 - 10:49 AM
Posted 30 December 2013 - 12:07 PM
Posted 30 December 2013 - 12:15 PM
Posted 30 December 2013 - 01:08 PM
two are dovetails two were linear bearing slides. They perform better than an standard R&P and way better than a Crayford. I'll post a pic of the one on my 6" F8 newt.
Posted 31 December 2013 - 02:43 AM
Did I get that right? So it is a neat but logical evolution of the track type crayford...
Posted 31 December 2013 - 03:19 AM
Posted 31 December 2013 - 10:45 AM
Posted 31 December 2013 - 11:10 AM
Posted 31 December 2013 - 01:34 PM
Posted 31 December 2013 - 03:52 PM
backlash free lead screws can be pretty expensive.. but they are available off the shelf..
Any good off-the-shelf micrometer head is backlash free.
Posted 31 December 2013 - 10:06 PM
Posted 31 December 2013 - 11:31 PM
Why not use a leadscrew?
Wouldn't the lead screw get in way of the eyepiece? Don the lead screw on your focuser is off to the side.
Posted 01 January 2014 - 12:25 AM
Posted 01 January 2014 - 12:34 AM
Posted 01 January 2014 - 02:03 AM
Posted 01 January 2014 - 06:35 AM
It took me a while to find pics of the dovetail R&P focuser on the Zanteson 6" f/5 Jaegers:
That looks similar to the helical R&P dovetail slide from an old American Optical Cycloptic microscope like mine as shown below. Backlash on the R&P and play in the dovetail slide are adjusted at the same time by rotating both knobs against each other.
Posted 01 January 2014 - 07:03 AM
One of my linear bearing units used a micrometer head for focusing.
As does almost every linear stage in the Newport catalog unless direct driven by a linear motor: http://www.newport.c...33/content.aspx
I really like the idea of direct drive. At one time I used an Electroglas 1034X wafer prober. The platen was floated on an air bearing above a Sawyer XY linear stepper drive- no contact, stiction free, backlash free precision movement. http://machinedesign...ve/motionsys... The Electoglas 1034X was a vast improvement over their original model that used rotary steppers to drive leadscrews to an ball bearing XY stage. I know because I actually have an original electroglas leadscrew wafer prober bought to work as a caustic tester.
I am thinking of a similar direct single axis drive to replace the leadscrew in my focuser, perhaps servo voice coil or Sawyer linear stepper. The drawback is power must be applied to hold position.
Posted 01 January 2014 - 07:48 AM