UNF Screw Thread per ANSI B1.1
UNF = Unified National Fine Screw Thread. This is one of three graded series: UNC (Unified National Corase); UNF (Unified National Fine); and UNEF (Unified National Extra Fine). The Nominal Major Diameter and Threads-per-inch (Pitch) are defined by ANSI/ASME B1.1 and are the choices for the customary Unified screws and nuts.
Nominal Diameter	Major Diameter Inch	Major Diameter mm	Tapping Drill Size mm	TPI	Pitch mm
#0 - 80 UNF	0.0600	1.524	1.25	80	0.317
#1 - 72 UNF	0.0730	1.854	1.55	72	0.353
#2 - 64 UNF	0.0860	2.184	1.90	64	0.397
#3 - 56 UNF	0.0990	2.515	2.15	56	0.453
#4 - 48 UNF	0.1120	2.845	2.40	48	0.529
#5 - 44 UNF	0.1250	3.175	2.70	44	0.577
#6 - 40 UNF	0.1380	3.505	2.95	40	0.635
#8 - 36 UNF	0.1640	4.166	3.50	36	0.705
#10 - 32 UNF	0.1900	4.826	4.10	32	0.794
#12 - 28 UNF	0.2160	5.486	4.70	28	0.907
1/4" - 28 UNF	0.2500	6.350	5.50	28	0.907
5/16" - 24 UNF	0.3125	7.938	6.90	24	1.058
3/8" - 24 UNF	0.3750	9.525	8.50	24	1.058
7/16" - 20 UNF	0.4375	11.112	9.90	20	1.270
1/2" - 20 UNF	0.5000	12.700	11.50	20	1.270
9/16" - 18 UNF	0.5625	14.288	12.90	18	1.411
5/8" - 18 UNF	0.6250	15.875	14.50	18	1.411
3/4" - 16 UNF	0.7500	19.050	17.50	16	1.587
7/8" - 14 UNF	0.8750	22.225	20.40	14	1.814
1" - 12 UNF	1.0000	25.400	23.25	12	2.117
1-1/8" - 12 UNF	1.1250	28.575	26.50	12	2.117
1-1/4" - 12 UNF	1.2500	31.750	29.50	12	2.117
1-3/8" - 12 UNF	1.3750	34.925	32.75	12	2.117
1-1/2" - 12 UNF	1.5000	38.100	36.00	12	2.117
UNF Screw Thread

Disclaimer:
This data is provided for general information only. The intention is to provide accurate information; regardless; errors may exist in the supplied information. If accuracy is critical, base your final decisions on the data provided in the root document: ANSI/ASME B1.1:2003; which is a copyrighted document. To purchase a copy visit an Authorized Reseller.

Comments:
Original Posting: 7/14/2009
Last Revision: 5/16/2016
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