Hi, I am new to this! I am struggling to answer the following: what size ( torque etc. ) 6 volt dc. planetary gear motor would I need to lift a 3kg. load vertically. I plan to couple the gear motor directly to a 12mm dia. steel acme lead screw with a 3mm pitch. The load I will attach to a brass lead screw nut. A stainless steel guide will stop the nut rotating and so give it vertical travel. Any better guesses out there than mine ? Thanks all.