NPTF Thread, improved surface finish and product consistency. 。 。 。, but are more brittle and must be used with rigid toolholding systems 。 CoroThread 266 is a threading concept for all types of threads. Designed with an iLock interface to combat extreme forces placed upon the insert during threading operations. U-Lock and Twin-Lock / for external threading, Sandvik Coromant 266RG-16NF01A270E 1125 PVD Coated Solid Carbide CoroThread 266 Threading Insert. NPTF Thread, 27: Industrial & Scientific. Inserts threading. T-Max U-Lock, 27: Industrial & Scientific. Sandvik Coromant 266RG-16NF01A270E 1125 PVD Coated Solid Carbide CoroThread 266 Threading Insert. this tool guarantees excellent insert stability for ultimate accuracy. Lay-down with center screw 。 Inserts for external threading 。 Solid carbide tools offer long tool life and faster cutting speeds than other substrates.