This is an X axis carriage that mounts to a linear rail that I designed for my Ender 3. It uses a direct drive BMG extruder and pancake stepper. I added a fan duct on the stepper that uses the original part cooling fan, as it does get a bit warm and there is not room for a heat sink.
Belt attaches via clamps on the bottom of the carriage. I feed mine through the hole and then into the clamps so as to keep the belt as straight as possible.
I have been continually modifying this for a bit now and will likely continue to do so.
75% or more as this is structural