Motor shaft to nut

Does anyone have advice on how to hook a motor shaft to a nut? I will need gearing for some torque, but I haven't found any products that allow you to hook gears to a nut. Does anything like that exist?

You want to do both, fix a nut to a shaft and fix a gear to a nut? How big is the motor? - Scotty

What is 'hooking' ??

What type of shaft ? round, splined, keyed, flat ...

What does the gear have for a hole? a spline, a round hole, a keyway, a grub screw hole?

As scotty asks: you mention shaft, then gear - you mean gear to shaft with nut (and how?) or two separate tasks?

And why a nut?

There are long nuts normally used for joining threaded rods. These can be drilled up to the shaft diameter

best to send a couple of pictures.

you ask for a shaft to a nut
and also gears to a nut.

and in most cases, you never use a nut with a stepper.

also, once you start adding things to the end of the shaft, the possibility of the torque creating problems increases.
best to have a jackshaft and the gear on that.
or mount the gear on to the shaft directly.

if you want to drive something, the most common way is to use a belt. the tiny belts you see on scanners and such are XLT google 'stepper xlt pulley' to get a look at some ideas.

http://www.sdp-si.com/web/html/products.htm

take a long nut, put a bolt in it, drill the hole for the shaft and you have a connection.
gearing is another problem, or use a belt like above mentioned.