Summary

38 mm hanging spool bearing.

Materials:
12 mm m3 x 4

1/4 inch countersink bit (to ream the acme rod hole)
C clamp or vice to jam in chain
appropriate pre drill bit for your chain.
2 zip ties incase the plastic de-laminates.

Instructions

Print out 2 adapters, 2 bearing holders (i just repaired the original and slapped two on the plate for the stl posted here) and 2 chain adapters. I use 1 infil for these because it is hanging above a glass desk.

Ream the acme to 608 adapters with the quarter inch countersink. Hold it with something so you dont mangle your hands with the drill, I used pliers .
You might need to file the 608zz surface slightly with a nail file. I like filing you get a better fit if you work at it. I use a dollar store nail file.
Once they fit nice and snugly in the 608zz bearings , make sure your acme bar fits in. One side should be tight , one considerably looser.
Jam your chain in the adapters. I used a 10foot box of chain from standard hw supply. About 34mm x 11mm on each link. I used a drill to slightly widen the hole then a c clamp to jam it in there. Slap a set screw in to lock the chain in so vibration doesnt ruin your day.

Slide in the acme bar , lock one set screw and tiewrap it around the chain link and the bar. IF the plastic breaks this will save your day. The other do the same but leave it loose so you can mount spools. It will grip the acme bar and lock it on but I still use a set screw on both sides. It will be a really really bad day to have a 2 lb weight crash into my printer / glass desk.

Everything should be tight.

38mm hanging spool bearing system