Never Underestimate the Value of ViseGrips

I was trying to put my mill back together.   There is a screw that holds down a gear thst provides antibacklash on the Y thread.  It is in a very awkward position.   I did not know exactly what size hex head wrench it required.  None seemed to fit and turn it.  So I disassembled it all to use a screw extractor.  

The steel was hard enough that a 5/64" drill did nothing at all to make a pilot hole for the left handed extractor.

Last effort.  ViseGrip on the screw head would not lock down.  I was afraid that locking on the star gear would damage it and unlike the screw, that is not a part you find at Tacoma Screw.   But turning it imparted enough force on the screw to create a gap between screw head and star gear to get a good grip on thr screw head alone.  It backed out.  The head was fine once cleaned out.  3/32" wrench works fine.