Well, something like the cam-track. But due to lack of expertise and the needed parts, the next best thing is to take a light small GEM and try to make it proper for a grab&go, airplane fit, AP tracker for a DSLR. Thus I'm looking for set of small hobbed worm/worm gears , bearings and so, in order to fix the extraordinarily huge PE, backlash and play these small GEMs have.