Installed new Bowden extruder motor mount to vertical frame leg.  Bracket has very tight tolerance to the NEMA17 motor body, so that the motor almost snaps into the mount.  The attachment is actually very solid, even though it is made by wrapping some cable ties around the motor in an “X” pattern.  It mounts to the 15mm wide extrusion rail with two 8mm M3 hex-head bolts, and two standard M3 nuts in the rail.

Clearance from rail is enough to allow linear slider wheels to pass by.

Drawing is available from my github area.