Bearing spool holder for the FLSun V400, though I imagine it will probably work with other printers as well. This sits on top of the regular spool holder, and provides a bearing interface, and GREATLY reduces force required to rotate the spool!

The spools consists of the following:

1x Lower bearing race
32x bearings
4x bearing carriers
1x bearing shim
1x Upper bearing race
1x end cap

To assemble:

1) First take the lower bearing race, and place it facing up in front of you.

2) Then take a bearing carrier and place it on to the lower race.

3) This is the tricky part, you have to sandwich the bearings between the first carrier you put down, and a second carrier to control the other end of the bearing. If you're having a hard time this, that's natural, take your time. It might help if you have a sowing needle, or similar, which you can reach through the carrier holes with to help align bearings

4) Next you put on the bearing shim (or spacer), this will separate the first bearing set from the second bearing set.

5) You basically repeat step three to assemble a second bearing set on top of the shim/spacer you just put down.

6) Carefully slide the upper race over both sets of bearing assemblies. I say "carefully" because if you jostle the bearings (before they are fully captured) they will fall to peice on you, and you'll have to start over.

7) Snap the end cap in place, and work it down until there is just enough freedom to allow for smooth rotation. This end cap should be a firm pressure fit, as it retains the entire assembly.

Congratulations, you now have a fully assembled bearing spool holder! Let the good times roll!