pinion gearing and difference in sizes
 

hi guys here is my first of many questions, i have sourced a company called Marchant Dice Ltd who supply steppers and controlers along with rack and pinion systems.
My question is,does the pinion have to be geared or can it be fitted directly on to the stepper motor? if so does it make much of a difference to fit their 20T or 30T pinion? their rack seems to be standard pitch so what difference is there between the two units? sorry for the stupid question, but i have absolutely no experience in this field.

cheers in advance:confused:

It has been coved to many times to repeat it…..in my opinion
I think the best advice I should give ya is…..
YOU NEED TO READ, READ and do even more reading before asking those basics ( covered) questions
Nothing personal here……you’ll be glad having read lots….will become handy FOR YOU after all !
......See this....
Cheers, Robert ;)

There are lots of machines running with pinions connected directly to the stepper motors. If you are referring to imperial measure rack, there are guys running in the 20T to 30T range. Not sure for metric rack if that range would be ok.

See Understanding & Selecting gear pinions - setting the steps per mm[inch]
and


Sticky Thread Why must the gear teeth be so small or fine?

To get a feel for the subject. :)

heath

cheers for the info, some thing that i can work with....as i have said earlier, i know a sum total of zero on this subject, but i assume that if it was geared lower it would be more accurate (is this correct?) and if it was directly connected to the shaft it would need a higher torque????? any how thank you for the link

You are correct on the gearing, lower gearing increases the torque to the pinions, at the cost of a lower top speed. This also increases the resolution at the same cost. For direct drive you would need a higher torque, but if you use the suggested motors ,
Selecting motors for the MechMate
you could use them direct drive. Have a look at some of the build threads and see who is using direct drive. Kobus' #6 is using direct drive as I recall with good success as well as others.