[bojan]

Finally, I put together another set of gear boxes for my EQ6.
As I described earlier in this thread, previous modification almost halved the PE, introduced by original gearboxes.
However, what bothered me was the residual 3-5arc-sec pp component, caused by transfer gears (47 teeth gears, they are different, with smaller modulus, and it seems of better quality in newer mounts with Synscan).
So, I decided to go for timing belt coupling as my next attempt to further reduce PE, or at least to have it smoother, so the future auto-guider can do its job properly.
The belts and pulleys came from Small Parts & Bearings, and overall reduction is 1:16, same as in previous version [20:80 spur gears pair (I wish they were helical) and 12:48 timing belt pulleys].
This gives 1:2880 at motor axle, and resolution is 2.2500 arcsec/step or 0.0703 arsec/u_step (at 32 /u steps as per Darren's firmware)

The details of the gearbox design are visible on the attached photo.
I expect the installation of those gearboxes may prove to be quite challenging job.. and if all goes well, my EQ6 should be as close to the perfection as it can be...