If it's just a recess for the head of the bolt it actually could be drilled 3/4 of the way threw and tapped for a treaded rod. That would be the easiest way. Instead of cutting the hex in. I'm also a cnc machinist/ programmer. Been doing this for 15 years
Can you still get these pleaseHi, I am too new to PM you apparently, I am very interested in order 2 sets of these for my FX5, could you pm me or email me at c_steig@hotmail.com
Thanks
Connie