How the flip do you remove the Z-axis stepper motors

I’m aware that there are the four screws holding it to the mount and the coupler is attaching it to the lead screw, but how on earth do you loosen the coupler from anything? I’ve tried all of my hex keys but none seem to fit it quite right. I don’t want to go at it however I want and strip all of the screws. Anyone know the actual size key to use on the couplers, or if there’s something else I need to do to get the motor off?

It is a 1.3MM. But they probable have thread lock on them, which it makes them hard to remove.

Are you having a hard time loosening the grub screws holding the couplers to the shafts? If so, heat them first by placing the tip of a soldering iron on the grub screw. The heat will soften the thread locker.

I’ll add (very little) to this for future Googlers. I found the grubs impossible to remove without destroying them. Of the four screws, only one came out after applying heat, oil, and lots of frustration. I ended up using highly precise instruments like a drill and a hammer to get them off. Good luck!

Its pretty much impossible without destroying them. It is very annoying that they use loctite now on them and it plugs the hole for unscrewing also. I have two taz 4’s where they did not use loctite and have never come loose.