UPDATED January 4th I made more room for X-axis travel and should be the full 175mm of X-axis of travel. Sorry to those who downloaded the original version and printed. You may be able to trim the ExtruderClamp like version 2 on the side that gets near the X-axis motor pulley.
This is a belt clamp for the QU-BD 2Up/One Up extruder. This is to avoid the use of glue to attach the extruder to the belt. It has worked well for me. NOTE: I have not tested it on a One Up printer.
Assembly: Looking at the extruder back side (belt side) I attached the extruder belt clamp with a M4 by 8mm long cap screw into the hole on the left side. The M4 will self-thread into the MDF and hold it secure without interfering with the Filament spring loaded clamp 3/8-16 button head cap screw. Let the right side remain unattached while attaching the extruder assembly to the two linear bearings on X-axis gantry. Once the extruder is attached to the X-axis gantry linear bearings then close the clamp onto the belt and then use a M3 by 8mm long cap head screw (or equivalent) and thread into the hole of the printed clamp.
I have printed it at .25mm layer height and .20% infill with only one perimeter (or wall) using PLA material. I printed with the flat side on the build plateform not as it is shown in the 3D STL model view.