Review on HHIP 3902 3070 Piece Expanding Mandrel by Sam Anez

This is an expander mandrel. Good surface hardness, unaffected when used with annealed 4140 steel. Holds well and squarely in machined holes. got a job for me The best advice is to move between centers with the dog. There isn't much open ending to cling to. Between centers with little threading, I got <0.001 TIR on the part I machined with it. Good enough for my needs.