Hi everyone,
I'm looking at fitting the Argo Navis to my big dob. I'm looking at doing the installation using the hardware that came with the system that I bought.
The hardware I've got are:
* 2X encoders fitted with timing pulleys, 36.7mm diameter
* 2X 70mm timinig pulleys, with hubs, and 31.5mm bore. Two locking grub screws are tapped into each hub.
* 2X timing belts.
Azimuth: my idea is to fit the encoder onto the ground board with the timing belt system located in the space between the ground board and the rocker box. My question is how can I fit the 70mm timing pulley around the azimuth pivot which is a 10mm metric stainless steel threaded bolt. I realise I may need to cut a hole into the ground board to accomodate the encoder - that's not a big deal really, and I'm quite happy to do that. Just how do I fix the large timing pulley,

.
Do I just centre it around the pivot hole of the ground board and screw it into place?
There is not enough clearance between the OTA's mirror box and the rocker box to fit the encoder inside the rocker box.
Altitude: Thing here is I would like to make the encoder a removeable component. Needs to be for transportation and storage purposes. So I'm looking at mounting the encoder directly onto the altitude tangent arm, and make a little coupler to sit on the altitude bearing. The altitude tangent arm can then be readily removed/replaced, and the encoder just slips in and out of the coupler. This is the simpler solution.
The other is to stuff around with timing belts and pulleys on the tangent arm, but this is too complicated.
Any other ideas for the altitude encoder?
Still, my main concern is the azimuth connection.
The first pic shows the 70mm timing pulley. The second pic the encoders with their fitted timing pulleys. The third the altitude bearings of my big dob.
Any ideas, suggestions, techniques, machining places, etc, is greatly appreceiated.
Mental.