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Hardware advice - keyed shafts


Aneil
 

Hi guys,
I've stepped away from this project for a while but mouser finally sent me the last parts for my MaxPCB board.  I am now looking at my power train, but am stuck trying to find an 8mm keyed pulley gear or shaft of some sort to engage from my stepper motor. Here is my stepper motor.

Does anyone have any advice on where I can either source an 8mm keyed pulley gear or remove the keyway entirely without damaging the shaft?  I've looked through McMaster-Carr but haven't found a solution, either due to my own inexperience or lack of keyed bore gears.

Thanks!
Aneil


Mike Ahner
 

Hi Aneil,

Those keys (also called woodruff keys) are just pressed into the shaft and since you're are new, you should be able to easily pop them out. Woodruff keys come in different sizes and a variety of shapes but they are all semi-rounded on the bottom and are designed to pop out. If you have a small cold chisel you can tap it gently with a hammer on one end which will pop up the other end. Then you can pry it out or use pliers to pull it out. If you don't have a small enough chisel just use a small screwdriver to pry with from the front. Since yours are new, you shouldn't have any trouble getting them out.

You don't really need to put them back, just run a set screw down thru the slot or avoid the slot altogether.

You can search for woodruff key removal but most of those will be for car axles and bigger stuff that's stuck on from years of use. Yours should be easy.

-Mike


Aneil
 

MIke,

Thanks for the advice! I'll work on it tomorrow and see how far I get. That sounds pretty easy!

Best,
Aneil


Mike Ahner
 

If you do need to tap the key with a small hammer, you might like to put a block of wood under the motor shaft to support it. If need be, you could also use a small clamp to hold the motor solid to the bench & the wood block. It should be tall enough to hold the motor just at or slightly off the work bench so that any shock from the hammer goes into the wooden block. But really, it shouldn't take much at all and since your motors are new, I would be surprised if you had to more than pry the keys out with a flat screwdriver.

Good luck!
-Mike


tomofreno2000
 

Best to clamp the shaft in a vise between two wood blocks to prevent marring the shaft. Otherwise you might damage the bearings when whacking on the key.