extreem slow/percise stepper control

i would like to drive a stepper on the order of 1000's (5000-10000?) steps per 1/3 of a revolution (a 400 step / rev .. 1.8deg/step will not work ...)

how easy is it to attach a stepper to attach a stepper to a worm/planetary gearbox ?

or is there a source of dc motors that could be driven at ~ .1 -0.05 RPM (600sec/rev - 1200sec/rev)

ralphnev: i would like to drive a stepper on the order of 1000's (5000-10000?) steps per 1/3 of a revolution (a 400 step / rev .. 1.8deg/step will not work ...) how easy is it to attach a stepper to attach a stepper to a worm/planetary gearbox ? or is there a source of dc motors that could be driven at ~ .1 -0.05 RPM (600sec/rev - 1200sec/rev)

Wow that's pretty demanding. To answer your question try this site http://en.nanotec.com/steppermotor_lowcost.html. The alternative is a something like a telescope taracker motor or is your demads are not heavy you might want to look at an egg turner motor that does 1 revolution every 2 hours.

hmmm .. nice ones -- a bit more serching has brought me to www.servocity.com which has Worm Drive Gearbox (Vertical Shaft) Product # WDG30P used with a 1 RPM Gear Motor Product # RZ12-3000-1RPM gets me down to 30min/Rev which is roughly where i want to be ... (they also have a 0.5 rpm .. 1hour /rev .... might be too long ... not inexpencive & i'm worried about vibration but may have to try it ....

For that resolution you may have issues with backlash - do you need to change direction ever? If so then a low- or zero-backlash geartrain will be needed.

only need to change direction at the end of a run (1/3 of a revolution,10min or so)

I'm mostly conserned about vibration/ this mech. will be holding optics