1) Re-align the tail-stock on your lathe to eliminate that slight taper when turning over a long distance. 2) Manufactured from EN31 Alloy Selected Steel. 3) Useful for alignment test between centers as well as in Morse Taper Spindles. 4) Accuracy within 1 to 5 micron. 5) Max.run-out : 0.0002". 6) Overall length : 13-3/16" ( 335mm )