Threading TN60252019608TN602520196182019622 Laydown Threading Threading Inserts P ⅷ M ⅷ API Round-External ⅷ first choice K ⅷ ࠗ alternate choice N ࠗ S ⅷ H ER-APIRD insert thread catalogue number RC EX E size pitch mm TPI TPF right hand 3ER10APIRD 0,34 1,2 1,4 3 — 10 .750 API Round-Internal IR-APIRD insert thread catalogue number RC EX E size pitch mm TPI TPF right hand 3IR10APIRD 0,34 1,2 1,4 3 — 10 .750 3IR8APIRD 0,40 1,3 1,5 3 — 8 .750 F64 widia.com