This is the base of a ball value. My intent is to use it when I need specific ball valve based projects. It is most helpful to people who use FreeCAD and want to use it as a base for their ball valves as well.

To create a ball valve:

1. print the housing and the ball
2. print the stem, grease and install a 12 mm OD x 1.5mm CS Oring
3. print two of the inserts and on each install a 24 mm OD x 2.4mm CS Oring, an 18 mm OD x 2.4 mm CS Oring, and a 21 mm OD x 2.4 mm CS Oring. Grease all orings with silicon grease.
4. print the handle

Then assemble

1. Use the key on the handle to screw one of the inserts into the housing - don't go too far, you still want to leave room to adjust the ball at this point.
2. slide the ball into the housing and up against the insert such that the slot for the stem is visible through the stem housing.
3. slide the stem into the housing and into the ball
4. put the second insert into the housing, again using the handle to screw it in place
5. do not tighten insert against the ball too much - too much and you won't be able to turn the ball - you make break a stem or catch an oring. leave it a bit loose and adjust later
6. put the handle on the stem and test the mechanism.