supply of driving ring and 90 degree centre unit. (2 items).driving ring and 90 degree centre unit. (2 items).,90 degrees centering unit for third line lathe machine material : 20mncr 5/en-20 7 case hardening to 62-65 hrc case depth - 1-5 - 2mm accuracy - axle play max 0.02 tir - 0.15 align ment to taper shaft max 0.02 note: the preference will be given for proven sources in the center manufact uring at any govt. organization [ warranty period: 30 months after the date of delivery ] ] , driving ring for hyt lathe machinesize:dial31.90mm x thickness46mm x id46mmdimensions material: m2 hardness 61-63 hrc with case hardening depth of 1.80 to 2.20mm [ warranty period: 30 m onths after the date of delivery ] ] => limited