I like Jigs too.
It's often the case that the set up time to do a job far exceeds the actual machining time involved, but without a safe, secure hold of the workpiece, you cannot make a start. Jigs do not need to be flashy, they just need to do their job.
I made this from 40mm extrusion off cuts that we use to make machine guards, to help out a workmate whose XB primary case had suffered the usual catastrophe.
As I do not have exclusive access to the mill, I made it tall, so that I could use the machine without removing the vice.
Once set up, the machining time is less than 5 minutes.
He didn't want to go the bolt up route, so I made him a washer to weld in.
Then I made a bung to centralise it. It's made of delrin, because I didn't have any other material, but it will be good enough to get it tacked in place.
I would have gone the simpler route of screwing in a plate and using dome nuts on the outer cover. But this is what he wanted, so that's what I did.