About this 3D model

This is a two-piece adapter that allows a J-Head MkV to be securely mounted on the "Jigsaw Replacement Extruder mk3" by lawsy et al. It can also be used to mount the original Makergear-style hotend without the plywood plate (which I've always found rather inelegant anyway). Note that this design occupies the mounting bosses normally used for the accessory mounting system. Then again, now you have the plywood plate mounting holes at your disposal...