No need for that, friend. I've been a tradesman for forty years, and have done a fair amount of wrenching in my days. I just never ran into a set of screws so tightly bound before.
This really ain't rocket science, and I'll probably have the whole assembly apart by tomorrow. In the meantime, my machine is still running on its other two drives. I'll get the third one back online by this weekend at the latest.
I do appreciate the concern and good advice.
I have seen loc-tite and or interference screws used in the type of application you describe. Manufacturers are more concerned with vibration loosening the parts than you being able to easily service. They want to sell you a new expensive part.
You may have to drill those heads off.
You may find a better quality allen bit socket somewhere too.