I noticed some dragging on my Taz 5 spool arm. I didnt like anyone elses ideas I found online. I really like the stock mounting location on the Taz and I like how it pivots a little. So I cut up a taz arm and combined it with the idea "mde091234" had going of using a screw rod.
My screw rod is a little bigger than 7mm. it fits nicely in the 608z bearings i have. i have 2 washer, 1 nut, and 1 locking nylon nut. a wing nut would be nice to substitute the outside nut.
you will need the rod, and 4 bearings (608Z) i dont know the difference between 608Z and 608ZZ that the other user was using.
Grabbed part of my spool arm from Lulzbot
I grabbed the spool cone from:
I printed this in ABS and it came out great. the natural shrinkage worked out really well. I was able to thread the rod onto the arm part and then secured it with the locking nut. it wasnt going anywhere after that. I placed a washer on the rod next and put the inner spool cone on and secured it with a regular nut. When I was loading the bearings into the spool cones, they were a nice snug fit. I loaded the next spool cone on, then a washer and finally the last nut. preferably you should use a wing nut here but i didnt have one available.