# Double lead nut on double shaft stepper motor

Hi,

I`d like to move two lead nuts using a stepper motor (also called travel nut). The result I want to achieve is to have a motion that goes back and forth.

I was wondering if I can use 2 travel nuts on a single double shaft stepper motor to achieve a back and forth motion?

Why do you think that might not be possible?

Without a clear diagram showing what you want to make I can't think of anything else to say.

...R

LarsHuisman:
Hi,

I`d like to move two lead nuts using a stepper motor (also called travel nut). The result I want to achieve is to have a motion that goes back and forth.

I was wondering if I can use 2 travel nuts on a single double shaft stepper motor to achieve a back and forth motion?

I think you will need a lead screw for the nuts to travel on. Drawing definitely required.

Paul

Robin2:
Why do you think that might not be possible?

Without a clear diagram showing what you want to make I can't think of anything else to say.

...R

I'll draw up an example tomorrow to clarify what I would like to achieve, the reason I'm asking is that I couldn't find examples of projects that use both shafts of a stepper motor with traveling nuts.

LarsHuisman:
I'll draw up an example tomorrow to clarify what I would like to achieve, the reason I'm asking is that I couldn't find examples of projects that use both shafts of a stepper motor with traveling nuts.

You have to have a different definition of "traveling nuts" than everyone else has. What makes nuts travel on the smooth shafts of stepper motors?

Paul

LarsHuisman:
I couldn't find examples of projects that use both shafts of a stepper motor with traveling nuts.

The nature of invention is to try new things to see if they work

...R

Sorry for this late reply, I’ve been thinking about the hardware part and looked at stepper motors with leaded screw, however it seems that the ‘through shaft’ or double shaft types move the entire shaft back and forth. That means that when I put a travel nut on one of either shaft, the travel nut won’t travel, right?

I’ve added a picture of the type of stepper motor I’m talking about as an attachment.

...R

AFAIK with that type of stepper motor the lead-nut is inside the motor and the screwed rod is moved in and out without rotating. Consequently you don't need travel-nuts on the screwed rod.

Maybe it would be possible to take the motor apart and fix the internal lead-nut to the screwed rod so as to make the rod rotate and then put your own travel nuts on the ends of the screwed rod. But DON'T come to me if you break the motor.

...R

So after the xyproblem part, can we discuss what you are actually trying to do?

Is this the idea?

I think the OP wants a motor with the lead screw projecting out both ends and two lead nuts.

...R

Robin2:
I think the OP wants a motor with the lead screw projecting out both ends and two lead nuts.

...R

I am still waiting to see what the OP really wants!

Paul

Robin2:
I think the OP wants a motor with the lead screw projecting out both ends and two lead nuts.

…R

Yes, correct! In the prototype i’ve made i’ve used two stepper motors to drive 2 plastic pieces that stretch a rubber band. However one of them gave out and the force of the rubber band didn’t play well with the motor so we needed to improvise and now i’d like to make a functioning machine.

I think placing two stepper motors ‘back to back’ with lead screws and travel nuts is the way to go, i’ve stitched the image below together to clarify what i mean.

LarsHuisman:
I think placing two stepper motors ‘back to back’ with lead screws and travel nuts is the way to go, i’ve stitched the image below together to clarify what i mean.

I suggest a single stepper motor driving a lead screw with both right hand and left hand threads.

Paul

If all you want to do is stretch something I can't see why there is a need for moving both ends of the piece.

...R

Paul_KD7HB:
I suggest a single stepper motor driving a lead screw with both right hand and left hand threads.

Paul

Oh wow, it didn’t knew about left handed and right handed threads, brilliant solution, thanks a lot!

Robin2:
If all you want to do is stretch something I can’t see why there is a need for moving both ends of the piece.

…R

Yes… It is a more of a design choice than a functionality choice

If left hand thread is hard to get, you can use gears to drive a second leadscrew in reverse.