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Topic: Changing the lead screw on a 3.5" floppy stepper (Read 1 time) previous topic - next topic

Candice

Hi all,

This is probably a very stupid question, but I'm hoping someone might know the answer.  I've got a  stepper motor out of an old 3.5" floppy drive.  It has a very short lead screw, but I have managed to find a 120mm long lead screw with a 2mm screw pitch.  I'd like to be able to remove the existing (short) lead screw and fit the new 120mm lead screw on.  The problem is that the existing lead screw appears to be glued onto the stepper shaft.

If (big if) it's possible to remove the glue, does anyone have any tips on the best way to go about it?  Use acetone?  Or something else?

If it's an impossible task, any idea on where I might find such a small stepper motor without a lead screw?

Thanks in advance,
Candice

Candice

Right, so acetone doesn't work. 

I tried to put the stepper in a vice and yank the existing lead screw off with a pair of pliers, but I killed the stepper.  Next, on another stepper I tried heating the lead screw in case there was some kind of adhesive inside which would melt and allow me to get the existing lead screw off, but again no luck. 

At this point I'm just going to order some lead screwless steppers from China and be done with it.  Good luck to anyone else trying this. 

Cheers,
C

Chagrin

I'm pretty sure the lead screw is the stepper shaft. It's not two parts.

EugeneNine

Most of the floppy drives I've torn apart the screw is the motor shaft.  I've had a few that I was successful at pushing the whole shaft out of the motor by disassembling it first, but very few. 
Also most of the ones I've found the front of the motor doesn't support the shaft, only the rear of the motor then the other end of the shaft all the way out.  So to extend the shaft you also have to move the support out as well.
Other issue is they are not very powerful, they simply move a small head sliding back and forth on a rod, they don't provide much torque for moving and arm or anything.


robwlakes

If you had access to an accurate lathe I would recommend cutting off the lead screw not too close to the motor and either turning a hole into the base of the new screw that (force?) fits over the old lead screw, or if length is not important, make a coupling that joins the two?
Learning Flute and C++, heading for a meltdown.

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