Dynabrade 78474 2-1/2" Dia. x 3/4", 8-32 Female Center Thread, A/O, 80 Grit, 8-Ply J-DynaCut Cross Pad, 100/pack 
Insize 4168-23E, STEEL STANDARD BALLS, 13/16″, 6940561981612
$22.34
To measure angle and diameter of taper holes
Material: tool steel
Hardness: HRC63
Diameter accuracy:?.00012?
Roundness .00004″
Supplied with manufacturer inspection certificate.
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