SwissTech: 1/2"X13 UNC Blue Ring Sp/Fl DIN376 HSS-EV Tap Spiral Flute (BLF) - UNC HSS-EV Oxidised Finish. For shorter blind holes. Taper lead to DIN form C (3 x P). Tapping tolerance to 6H. Manufactured to DIN 371/376. UNC - Unified Nationa…View more