This a industrial grade aluminum machine adapter that is manufactured by "Shagsall" / SDC LLC.
 
The adapter is approximately three inches long and one inch in diameter. The receiver end of the adapter is drilled and tapped with a female M12 x 1.25 threads You have approximately 1 1/4" of usable threads for strength.
 
Just simply screw your M12 x 1.25 threaded rod from your personal machine into the adapter and tighten down a jamb nut against the adapter to keep it from loosening up. Loc-tite is recommended when assembling the personal machine adapter.
 
The smooth surface is easy to clean.