Summary

The stock TAZ has some Z hysterisis, often called backlash. These parts remove a large amount of it, and make things like a software compensated bed-level probe possible.

Instructions

Print 2 sets of each part. I suggest ABS for the Z-nut, and Nylon for the motor to M6 parts to give them strength and flexibility.

You will need the following hardware:
-(8) M3 insert nuts (short ones) and tool to insert them (Mcmaster carr). Technically you can remove and re-use the ones in the TAZ parts you are replacing
-(2) extra M6 BRASS nuts (Mcmaster again)
-(8) M3x16 Bolts and Nyloc M3 nuts, mor the motor to M6 mount
-Springs and 2 brass M6 nuts from your existing TAZ Z-nut
-4 1/8" pins. Dowel or drills for assembly use only. 3mm material may possibly work instead
-(7-11) LM10UU linear Ball bearings...optional but recommended.

Disassemble the z-nut spring and PVC motor to M6 couplings on your TAZ.

Z-nut spring:
-remove the support material in the spring window with a knife.
-install the insert nuts in the 4 mounting holes.
-ream the 4 assembly holes to 1/8" (3.175mm) and test that the pins go in place easilly
-install one of the brass nuts all the way up in the hex pocket (see picture)

insert the 4 1/8"assembly pins in the holes. These are there to keep the nuts in place during assembly.
-insert the other M6 nut in the hex socket (see picture)
-compress and hold the spring between flat pliers, be carefull not to clamp your fingers, this can be tricky.
-push the compressed spring into the front slot of the Z-nut and push it in place. It should pop into the counterbore on the bottom and push up onto the brass nut.
-thread the M6 rod from the top nut, thru the bottom nut and spring and out the bottom.
-once the rod is in both nuts the assembly pins can be removed.
-grease the rod with your favorite grease, and thread it thru to where it needs to be to re-assembly.

Motor to M6 mounts:
-ream the 3mm holes if necessarry.
-Install the B-half up against the flat on the stepper motor
-install the A-half across from the B-half
-use the M3 screws and Nyloc nuts to hold the 2 halves together looselly.
-insert the M6 rod from above
-tighten the M3 nuts

Lulzbot TAZ anti-backlash Z-nut and motor to M6 mount mod