With a set of 3 effectorAdapters plus 3 carriageAdapters, you can adapt an Anycubic Predator to work with my MagBall Arms, using the stock effector. These use a center-to-center MagBall spacing of 76mm.
The advantage of using MagBall Arms is that they are zero-backlash, which improves auto-calibration and the ability to print details faithfully.
When installing the effectorAdapters, notice that the horizontal holes are oval, which gives them some extra freedom. First tighten the two M3x16 bolts only finger tight, and then slowly and alternately tighten them until snug. This helps ensure that the adapter seats symmetrically and correctly. By the way, these parts are printed upside down, with the nut traps on top, but should be installed with the nut traps on the bottom.
You can purchase sets of MagBall Arms directly from Haydn Huntley via email: firstname.lastname@example.org
Alternatively, you can use 3 smartCarriageAdapters with David Crocker's Delta Smart Effector. You can purchase these from:
The Delta Smart Effector uses a center-to-center MagBall spacing of 55mm.
Many thanks to Jay S. and John Giardino for helping me, suggesting improvements, and in John's case, actually testing them on his printer.
Here is a video John Giardino shot: https://youtu.be/jtPPRN12znc
These parts were inspired by some of Rizza81's designs: https://www.thingiverse.com/thing:3567642
They were also inspired by some parts which a person named Flint Read posted on Facebook: