STEP BY STEP
Unscrew one servo’s back (avoid disturbing gears in the top section). De-solder wires to motor and remove the three core cables and circuit board. Solder new cable to motor and refit. Repeat for second servo. You may need to enlarge cable slot to suit new cable.
Use the downloadable plan/template to mark out parts – adjust shape to suit your focuser (see main article). We used 18mm thick plywood made from some 15mm and 3mm offcuts glued together. Carefully cut out servo mount from thin plywood or acrylic.
It’s easier to drill holes in the plywood bracket and servo mount plate before cutting out the fiddly shapes as there’s more material to hold. The bracket holes accommodate two trimmed nails, which provide support for the cable ties. Smooth and paint finished parts.
Make a round wheel from thin plywood with a dowel handle for speedy turning. One of the servo attachments that comes with the kit is glued to the centre. Superglue a second attachment to the GT2 pulley (roughing up the surfaces makes the joint stronger).
Make a thicker wheel with a 48mm diameter. Drill the centre to suit the focuser knob. A small hole may be drilled radially to accommodate a grub screw so you can attach it securely. Glue the smaller GT2 belt inside out to the circumference of the wheel.
Use cable ties passing over the nails to attach the bracket. A rubber strip underneath aids the grip. Make sure the pulley and drive gear are in line before tightening. Fit the larger belt and remove slack before finally tightening the screws on the mount.