This modular ram mount extension uses a 17mm ball. The "arm" portion can be swapped out depending what shape you need. A screw (M4) is used to attach the ball or the socket to the arm. If you wanted to use 8-32 screws, you could probably get it to work since the major diameter is only .006" larger than the M4.

if you need help getting the screw started into the hole, you might want to use an M4 tap (or 8-32). Otherwise, just push harder!

the printed threads do not need anything special. The tap drill diameter for the nut was increased to 0.7mm (normally fitment is .12mm). For reference, the threads are M22x1.5

Anycubic

All-metal Mega

Doesn't Matter

Doesn't Matter

0.2

20%

only the arm uses a bed-facing support. Everything else does not.

ball: use a brim to increase contact on the print bed so it doesn't dislodge while printing
nut: can also use a brim, but you can probably get away without using it