UN fine (UNF) taps have more threads per inch than UN coarse (UNC) taps. - Compared to UNC taps, UNF taps perform better in threading applications on thin-walled workpieces and hard materials. - Fine threads provide more tensile strength and shear strength than coarse threads. - The bright finish on these taps provides a smooth, polished surface. Thread Size / 3/8"-24 Thread Standard / UNF Tap Material / High Speed Steel Tap Finish / Bright (Uncoated) Thread Length / 3/4 in Overall Length / 2 15/16 in 75% Thread Drill Size / 8.50 mm Thread Limit / H1 Class of Fit / 2B Thread Direction / Right Hand Number of Flutes / 3 Primary Material Application / All Materials 55% Thread Drill Size / 11/32 in 65% Thread Drill Size / R Drill Bit Size / Q Extended Neck / Yes Measurement System / Fractional Inch Primary Material Application ISO Code / N, P Series / SPGP Shank Dia. / 3/16 in Shank Length / 1 11/16 in Shank Type - Machining / Straight Spiral Direction / Neutral Square Size / 0.2860 in Standards / USCTI Table 302A Tap Chamfer / Plug Tap Grouping / Individual Tap Thread Size / 3/8"-24 Threads per Inch / 24 Thread Limit / Class of Fit / H1 / 2B