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shaft

12mm output motorgearbox

Hi I am looking to build a 4WD robot with 4 independent motorgearboxes. I have some wheels that I would like to use that have a 12mm hex hub. I need a motogearbox with high torque, and a threaded bar or a tapped hole at the end of the output shaft. Has anyone seen/heard of a motogearbox with these specifications? 

Shaft coupling from 0.125 D to 0.25 square

Hi, hoping someone can help me with what I think is a pretty basic question:

I have 2 motors with a 0.125inch keyed (or D) shaft.  I need to connect it to a 0.25" square socket (vex tank tread driver).  I assume there's some sort of coupler or adaptor that could help with this?  I've been looking for most of the afternoon and haven't found any good solutions but I imagine it's largely due to me not knowing where to look...this is my first robot so I'm a bit new to the whole connnecting a shaft thing...  many thanks for any suggestions or thoughts.

Gears and gearboxes. What do you want for your robot?

Sometimes when your building a robot you will need gears. Although there are plenty of ready made gearboxes on the market they will not always fit your needs. I have been looking at puting together a collection of gears, shafts and even small bearings so that you can build you own gearboxs.

I started off with the green bevel gears shown below, they have big, strong, chunky teeth that are hard to break. These allow you to have a 90° output.

What can I get away with in bearings?

I'm in the process of building up a drive system from scratch around a couple of high-torque NEMA 17 steppers.  The idea was to use a small V-Belt drive to provide a boost in torque so I could use larger wheels and get up off the floor a bit.  I have a 4:1 reduction going with an intermediate pully in addion to the drive and wheel pulleys.  I'm machining all the parts myself and have the pulleys made.  I wanted the ends of the wheel and intermeadiate pulley to hang free.  Looking at bearings it's become clear that even cheap ones if doubled up on the fixed end of ea

Low RPM Motor With High Torque Needed

I need a motor that has a lot of torque but the shaft looks like this:

 

GEARS.jpg

I CANT FIND ONE!!  I need it to be cheap though... If anyone knows anything at all, please let me know.  Thanks!

P.S. Even if I have to slightly modify the motor, that's ok for me too!