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UNC Threads UNF threads UNEF ThreadsTPI Unified Thread Standard

 

Unified Screw Threads - UNC, UNF and UNEF  specifications
Major diameter
(in mm)
Threads per inch (Pitch) Tap drill size - Preferred sizes 
Coarse (UNC) Fine (UNF) Extra fine (UNEF) Coarse Fine Extra fine
#0 = 0.0600 (1.5240) 80     3/64 in  
#1 = 0.0730 (1.8542) 64 72   #53 #53  
#2 = 0.0860 (2.1844) 56 64   #50 #50  
#3 = 0.0990 (2.5146) 48 56   #47 #45  
#4 = 0.1120 (2.8448) 40 48   #43 #42  
#5 = 0.1250 (3.1750) 40 44   #38 #37  
#6 = 0.1380 (3.5052) 32 40   #36 #33  
#8 = 0.1640 (4.1656) 32 36   #29 #29  
#10 = 0.1900 (4.8260) 24 32   #25 #21  
#12 = 0.2160 (5.4864) 24 28 32 #16 #14  
1/4 = 0.2500 (6.3500) 20 28 32 #7 #3  
5/16 = 0.3125 (7.9375) 18 24 32 F I  
3/8 = 0.3750 (9.5250) 16 24 32 5/16 in Q  
7/16 = 0.4375 (11.1125) 14 20 28 U 25/64 in  
1/2 = 0.5000 (12.7000) 13 20 28 27/64 in 29/64 in  
9/16 = 0.5625 (14.2875) 12 18 24 31/64 in 33/64 in  
5/8 = 0.6250 (15.8750) 11 18 24 17/32 in 37/64 in  
3/4 = 0.7500 (19.0500) 10 16 20 21/32 in 11/16 in  
7/8 = 0.8750 (22.2250) 9 14 20 49/64 in 13/16 in
  • ASME/ANSI B1.1 – 2003 Unified Inch Screw Threads, UN & UNR Thread Form
  • ASME/ANSI B1.10M – 2004 Unified Miniature Screw Threads
  • ASME/ANSI B1.15 – 1995 Unified Inch Screw Threads, UNJ Thread Form