[Update: I have a newer slip-on chuck mount that is very quick/easy yet secure.]

Threaded mount for 1¼-8 chucks, faceplates, and other lathe accessories. 

The weight is on the through-bolt or wood screw, so there is no chance of a layer separation dropping your gear on the floor. The extra nail or screw hole is just an inexpensive way to keep it from spinning.

Note: with default PrusaSlicer settings in PETG, I got some upward warping on the threads with made it too snug. I lowered my temp and fan speed, and increased the layer height from 0.15 to 0.3, and the threads came out well.

Designed in Fusion 360, threads ANSI Unified 1¼-8.