I thanked Max last I saw him for the wonderful trick of using a drill press vice on the shop bench to hold the receiver as a thirdhand.
Here's another great use for one. It would also be an excuse to justify the expenditure for a xy table that would be used like a mill table.
Where I'm lucky enough to get the front receiver piece, it's clamped on the table and drill out the existing rivets noting the amount of movement along the x-axis-- that gets the two upper ones done. If I'm confident enough to handle the backlash I will go ahead and get the lower one, otherwise-- another set up on it.
Micing the receiver piece will give the location of the front slice then orient the new receiver on the front and top edges.
I don't a clue what I'm doing, unlike Sang's Dad, but the holes are in the right place.