I am attempting to replace the X axis stepper motor with a new one. I see that I need to remove the pulley from the old stepper motor. I loosened the set screws on the pulley but I am still unable to remove the pulley from the shaft on the old stepper motor.
Is there any documentation that covers how to replace the stepper motors?
Is there a specific way to remove the pulley from the stepper motor without damaging it?
Any guidance would be appreciated.
Thanks,
Bryan McDowell
I don’t recall for sure, but it’s very possible there’s red Loctite on there, which is meant to be permanent.
I also had to purchase a new extension cable for the X axis and I just found that it included a new pulley. So I just need to install the new pulley on the new motor shaft. It looks like the shaft has a flat spot so I assume that the pulley must be installed onto the shaft a specific way.
Yes. Be sure the flat spot is centered under one of the grub screws and tightened onto that flat spot
Are there any images that show the correct orientation of the pulley on the shaft for the X axis motor?
On the old motor, the pulley is installed with the large end of the pulley bearing away from the stepper motor. See the attached picture “Old X stepper motor.jpg”
The pulley is installed with the large bearing closer to the stepper motor housing which is different from the pulley on the X stepper. See “Y stepper motor.jpg”
Which way is correct for the X Stepper motor? It seems like the pulley aligns on the shaft if the bearing is oriented closer to the stepper motor housing.
I’ve never seen one installed like in the first picture. The second picture is correct.
There are 2 set screws. One should be on the flat of the stepper motor. Some people replace those tiny set screws with cap screws of the same thread pitch. It is easy to strip those pulley set screws so use a good quality wrench and not the ball end of a ball ended allen wrench. Make sure the wrench is fully seated.
It’s been advised to tighten the setscrew on the flat before tightening the setscrew on the shaft surface. Thinking about this, I just realized that this will micro-clock the pulley to the flat, ensuring the firmest contact between the setscrew tip and the flat. The setscrew out on the motor shaft won’t do anything to disturb the pulley clocking, only possibly slide the first setscrew a little laterally on the flat depending on the clearance between the shaft and the pulley bore.
[disclaimer–mechanical engineer on his lunch hour]
Hi,
Both pictures are correct. On the “X” stepper, the thick collar goes to the outside end of the shaft, away from the motor, and on the “Y” stepper the thick collar goes inside or closest to the motor. The thick collar is to allow the threading for set screws.
As to removing the pulley from the old stepper motor shaft, loosen the set screws and pull away from the motor. If it seems stuck, after loosening the set screws, use a wrench to pry the pulley off the shaft. However, I do see where you mention you did receive a new pulley.
If locktite was used on the set screws, apply heat to break the bond.
side note, if you do have to pry the pulley off, only loosen the set screws about one full turn but do not completely remove them (this will help prevent the thick collar from separating from the toothed section. Also, it’s unlikely that locktite was used. That was a known issue with the SO3, pulleys, becoming loose. And looking at the old stepper picture I do not see any evidence of red locktite in the threads.
also, are you sure you need a new stepper motor? Those things last a Very long time.
Good Luck and have fun milling.
MC
I worked with Carbide 3D support to troubleshoot an issue in which the X-axis was not moving and causing the machine initialization to fail. I discovered that one of the female slots on the X-axis connector has a scorch mark on it. The corresponding pin on the X extension cable is also scorched. Therefore, Support suggested that I needed to replace the stepper motor and the extension cable.
Well, keep the original motor. You now have a spare.
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