At One Place

Unified inch thread chart

40 unified inch thread sizes, with the drill to tap each one and the hole to clear it.

Thread Pitch Tap drill Clearance Hex Torque
#0-80 UNF 80 tpi 3/64" 1.78 mm — —
#1-72 UNF 72 tpi #53 2.06 mm — —
#1-64 UNC 64 tpi #53 2.06 mm — —
#2-64 UNF 64 tpi #50 2.44 mm — —
#2-56 UNC 56 tpi #50 2.44 mm — —
#3-48 UNC 48 tpi #47 2.79 mm — —
#4-48 UNF 48 tpi #42 3.26 mm 6.35 mm —
#4-40 UNC 40 tpi #43 3.26 mm 6.35 mm —
#5-40 UNC 40 tpi #38 3.45 mm 7.94 mm —
#6-40 UNF 40 tpi #33 3.8 mm 7.94 mm —
#6-32 UNC 32 tpi #36 3.8 mm 7.94 mm —
#8-32 UNC 32 tpi #29 4.5 mm 8.73 mm —
#10-32 UNF 32 tpi #21 5.11 mm 9.52 mm —
#10-24 UNC 24 tpi #25 5.11 mm 9.52 mm —
#12-24 UNC 24 tpi #16 5.79 mm 11.11 mm —
1/4"-32 UNEF 32 tpi 7/32" 6.76 mm 11.11 mm —
1/4"-28 UNF 28 tpi #3 6.76 mm 11.11 mm 10.5–14.5 N·m
1/4"-20 UNC 20 tpi #7 6.76 mm 11.11 mm 9–12.5 N·m
5/16"-24 UNF 24 tpi I 8.43 mm 12.7 mm 21–29 N·m
5/16"-18 UNC 18 tpi F 8.43 mm 12.7 mm 19–26 N·m
3/8"-32 UNEF 32 tpi 11/32" 10.08 mm 14.29 mm —
3/8"-24 UNF 24 tpi Q 10.08 mm 14.29 mm 38–52 N·m
3/8"-16 UNC 16 tpi 5/16" 10.08 mm 14.29 mm 34–46 N·m
7/16"-20 UNF 20 tpi 25/64" 11.91 mm 15.88 mm 60–82 N·m
7/16"-14 UNC 14 tpi U 11.91 mm 15.88 mm 54–73 N·m
1/2"-28 UNEF 28 tpi 15/32" 13.49 mm 19.05 mm —
1/2"-20 UNF 20 tpi 29/64" 13.49 mm 19.05 mm 92–126 N·m
1/2"-13 UNC 13 tpi 27/64" 13.49 mm 19.05 mm 82–112 N·m
9/16"-18 UNF 18 tpi 33/64" 15.08 mm 20.64 mm 132–180 N·m
9/16"-12 UNC 12 tpi 31/64" 15.08 mm 20.64 mm 118–162 N·m
5/8"-27 UNS 27 tpi 15 mm 16.67 mm 23.81 mm —
5/8"-18 UNF 18 tpi 37/64" 16.67 mm 23.81 mm 185–253 N·m
5/8"-11 UNC 11 tpi 17/32" 16.67 mm 23.81 mm 163–223 N·m
3/4"-20 UNEF 20 tpi 45/64" 19.84 mm 28.57 mm —
3/4"-16 UNF 16 tpi 11/16" 19.84 mm 28.57 mm 320–440 N·m
3/4"-10 UNC 10 tpi 21/32" 19.84 mm 28.57 mm 290–395 N·m
7/8"-14 UNF 14 tpi 13/16" 23.02 mm 33.34 mm 515–700 N·m
7/8"-9 UNC 9 tpi 49/64" 23.02 mm 33.34 mm 465–640 N·m
1"-12 UNF 12 tpi 59/64" 26.19 mm 38.1 mm 765–1050 N·m
1"-8 UNC 8 tpi 7/8" 26.19 mm 38.1 mm 700–960 N·m

Plain steel property class 8.8 or SAE grade 5, dry threads, tightened to about 65% of yield. Lubricated threads reach the same preload at 20-30% less torque. Where the manufacturer publishes a figure — spark plugs, wheel nuts, cylinder heads — use theirs.

Sources

  1. Official vendor product documentation — At One Place
  2. Typical range compiled from manufacturer specifications — At One Place

How these figures are compiled and checked