Pitch Diameter Tables FORNOS.575AND585SCREWTHREADMICROMETERS Metric Standard p d f f 60º Whitworth Standard Caliper Reading or Pitch Diameter for Whitworth Threads = D - .640 N p = pitch = 1 No. thread per inch d = depth = p x .6495 f = flat = pitch 8 Diameter (in) Threads per Inch Caliper Reading or Pitch Diameter Single Depth of Thread D N D - .640 .640 N N — 48 — .0133 — 46 — .0139 — 44 — .0146 — 42 — .0152 — 40 — .0160 — 38 — .0168 — 36 — .0178 — 34 — .0188 — 32 — .0200 — 30 — .0213 — 28 — .0229 — 26 — .0246 — 24 — .0267 — 22 — .0291 1/4 20 .2180 .0320 5/16 18 .2769 .0355 3/8 16 .3350 .0400 7/16 14 .3918 .0457 1/2 12 .4467 .0533 9/16 12 .5092 .0533 5/8 11 .5668 .0582 11/16 11 .6293 .0582 3/4 10 .6860 .0640 13/16 10 .7485 .0640 7/8 9 .8039 .0711 15/16 9 .8664 .0711 1 8 .9200 .0800 1-1/8 7 1.0336 .0914 1-1/4 7 1.1586 .0914 1-3/8 6 1.2684 .1066 1-1/2 6 1.3934 .1066 1-5/8 5 1.4970 .1280 1-3/4 5 1.6220 .1280 1-7/8 4-1/2 1.7328 .1422 2 4-1/2 1.8578 .1422 2-1/8 4-1/2 1.9828 .1422 Size (mm) Pitch Intl. Std. French Std. 2 .45 .50 3 .55 .50 4 .70 .75 5 .85 .75 6 1.00 1.00 7 1.00 1.00 8 1.25 1.00 9 1.25 1.00 10 1.50 1.50 11 1.50 — 12 1.75 1.50 14 2.00 2.00 16 2.00 2.00 18 2.50 2.50 20 2.50 2.50 22 2.50 2.50 24 3.00 3.00 26 — 3.00 27 3.00 — 28 — 3.00 30 3.50 3.50 32 — 3.50 33 3.50 3.50 34 — 3.50 36 4.00 4.00 38 — 4.00 39 4.00 — 40 — 4.00 587 starrett.com R eference T ables