American National Thread
ANSI/ACME B1.5-1977

The ACME thread was developed as a compromise, to offer better strength than a V-form while overcoming the problems with the square thread form.
Diameter
"		 Diameter
mm		 Tapping Drill Size
mm		 TPI Pitch
mm
1/4" - 16 ACME 6,350 4,762 16 1,588
5/16" - 14 ACME 7,938 6,123 14 1,814
3/8" - 12 ACME 9,525 7,408 12 2,117
7/16" - 12 ACME 11,112 8,996 12 2,117
1/2" - 10 ACME 12,700 10,160 10 2,540
5/8" - 8 ACME 15,875 12,700 8 3,175
3/4" - 6 ACME 19,050 14,817 12 2,117
7/8" - 6 ACME 22,225 17,992 6 4,233
1" - 5 ACME 25,400 20,320 5 5,080
1 1/8" - 5 ACME 28,575 23,495 5 5,080
1 1/4" - 5 ACME 31,750 26,670 5 5,080
1 3/8" - 4 ACME 34,925 28,575 4 6,350
1 1/2" - 4 ACME 38,100 31,750 4 6,350
1 3/4" - 4 ACME 44,450 38,100 4 6,350
2" - 4 ACME 50,800 44,450 4 6,350
2 1/4" - 3 ACME 57,150 48,683 3 8,467
2 1/2" - 3 ACME 63,500 55,033 3 8,467
2 3/4" - 3 ACME 69,850 61,383 3 8,467
3" - 2 ACME 76,200 63,500 2 12,700
3 1/2" - 2 ACME 88,900 76,200 2 12,700
4" - 2 ACME 101,600 88,900 2 12,700
4 1/2" - 2 ACME 114,300 101,600 2 12,700
5" - 2 ACME 127,000 114,300 2 12,700
Nut Washer
Screw Nut