Socket Head Cap Screw Thread Lengths
| Nom. Size D | #0 | #1 | #2 | #3 | #4 | #5 | #6 | #8 | #10 | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Basic Thread Length LT | 0.500 | 0.625 | 0.625 | 0.625 | 0.750 | 0.750 | 0.750 | 0.875 | 0.875 | |||||||||
| Nominal Length L | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB |
| 3/4 | .25 | .19 | ||||||||||||||||
| 7/8 | .25 | .19 | .25 | .17 | .25 | .16 | .25 | .15 | ||||||||||
| 1 | .50 | .44 | .25 | .17 | .25 | .16 | .25 | .15 | .25 | .12 | .25 | .12 | ||||||
| 1-1/4 | .75 | .69 | .62 | .55 | .62 | .54 | .62 | .52 | .25 | .12 | .25 | .12 | .50 | .34 | .38 | .22 | .38 | .17 |
| 1-1/2 | .88 | .80 | .88 | .79 | .88 | .77 | .75 | .62 | .75 | .62 | .50 | .34 | .38 | .22 | .38 | .17 | ||
| 1-3/4 | 1.12 | 1.04 | 1.12 | 1.02 | .75 | .62 | .75 | .62 | 1.00 | .84 | .88 | .72 | .88 | .67 | ||||
| 2 | 1.38 | 1.27 | 1.25 | 1.12 | 1.25 | 1.12 | 1.00 | .84 | .88 | .72 | .88 | .67 | ||||||
| 2-1/4 | 1.25 | 1.12 | 1.25 | 1.12 | 1.50 | 1.34 | 1.38 | 1.22 | 1.38 | 1.17 | ||||||||
| 2-1/2 | 1.75 | 1.62 | 1.50 | 1.34 | 1.38 | 1.22 | 1.38 | 1.17 | ||||||||||
| 2-3/4 | 2.00 | 1.84 | 1.88 | 1.72 | 1.88 | 1.67 | ||||||||||||
| 3 | 1.88 | 1.72 | 1.88 | 1.67 | ||||||||||||||
| Nom. Size D | 1/4 | 5/16 | 3/8 | 7/16 | 1/2 | 5/8 | 3/4 | 7/8 | 1.000 | |||||||||
| Basic Thread Length LT | 1.000 | 1.125 | 1.250 | 1.375 | 1.500 | 1.750 | 2.000 | 2.250 | 2.500 | |||||||||
| Nominal Length L | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB | LG | LB |
| 1-1/2 | .50 | .25 | ||||||||||||||||
| 1-3/4 | .50 | .25 | .62 | .35 | .50 | .19 | ||||||||||||
| 2 | 1.00 | .75 | .62 | .35 | .50 | .19 | .62 | .27 | ||||||||||
| 2-1/4 | 1.00 | .75 | 1.12 | .85 | 1.00 | .69 | .62 | .27 | .75 | .36 | ||||||||
| 2-1/2 | 1.50 | 1.25 | 1.12 | .85 | 1.00 | .69 | 1.12 | .77 | .75 | .36 | .75 | .30 | ||||||
| 2-3/4 | 1.50 | 1.25 | 1.62 | 1.35 | 1.50 | 1.19 | 1.12 | .77 | .75 | .36 | .75 | .30 | ||||||
| 3 | 2.00 | 1.75 | 1.62 | 1.35 | 1.50 | 1.19 | 1.62 | 1.27 | 1.50 | 1.12 | .75 | .30 | 1.00 | .50 | ||||
| 3-1/4 | 2.00 | 1.75 | 2.12 | 1.85 | 2.00 | 1.69 | 1.62 | 1.27 | 1.50 | 1.12 | 1.50 | 1.04 | 1.00 | .50 | 1.00 | .44 | ||
| 3-1/2 | 2.50 | 2.25 | 2.12 | 1.85 | 2.00 | 1.69 | 2.12 | 1.77 | 1.50 | 1.12 | 1.50 | 1.04 | 1.00 | .50 | 1.00 | .44 | 1.00 | .38 |
| 3-3/4 | 2.50 | 2.25 | 2.62 | 2.35 | 2.50 | 2.19 | 2.12 | 1.77 | 2.25 | 1.86 | 1.50 | 1.04 | 1.00 | .50 | 1.00 | .44 | 1.00 | .38 |
| 4 | 3.00 | 2.75 | 2.62 | 2.35 | 2.50 | 2.19 | 2.62 | 2.27 | 2.25 | 1.86 | 2.25 | 1.80 | 2.00 | 1.50 | 1.00 | .44 | 1.00 | .38 |
| 4-1/4 | 3.00 | 2.75 | 3.12 | 2.85 | 3.00 | 2.69 | 2.62 | 2.27 | 2.25 | 1.86 | 2.25 | 1.80 | 2.00 | 1.50 | 2.00 | 1.44 | 1.00 | .38 |
| 4-1/2 | 3.50 | 3.25 | 3.12 | 2.85 | 3.00 | 2.69 | 3.12 | 2.77 | 3.00 | 2.62 | 2.25 | 1.80 | 2.00 | 1.50 | 2.00 | 1.44 | 2.00 | 1.38 |
| 4-3/4 | 3.50 | 3.25 | 3.62 | 3.35 | 3.50 | 3.19 | 3.12 | 2.77 | 3.00 | 2.62 | 3.00 | 2.54 | 2.00 | 1.50 | 2.00 | 1.44 | 2.00 | 1.38 |
| 5 | 4.00 | 3.75 | 3.62 | 3.35 | 3.50 | 3.19 | 3.62 | 3.27 | 3.00 | 2.62 | 3.00 | 2.54 | 3.00 | 2.50 | 2.00 | 1.44 | 2.00 | 1.38 |
| 5-1/4 | 4.12 | 3.85 | 4.00 | 3.69 | 3.62 | 3.27 | 3.75 | 3.36 | 3.00 | 2.54 | 3.00 | 2.50 | 3.00 | 2.44 | 2.00 | 1.38 | ||
| 5-1/2 | 4.12 | 3.85 | 4.00 | 3.69 | 4.12 | 3.77 | 3.75 | 3.36 | 3.75 | 3.30 | 3.00 | 2.50 | 3.00 | 2.44 | 3.00 | 2.38 | ||
| 5-3/4 | 4.62 | 4.35 | 4.50 | 4.19 | 4.12 | 3.77 | 3.75 | 3.36 | 3.75 | 3.30 | 3.00 | 2.50 | 3.00 | 2.44 | 3.00 | 2.38 | ||
| 6 | 4.62 | 4.35 | 4.50 | 4.19 | 4.62 | 4.27 | 4.50 | 4.12 | 3.75 | 3.30 | 4.00 | 3.50 | 3.00 | 2.44 | 3.00 | 2.38 | ||
| 6-1/4 | 5.12 | 4.85 | 5.00 | 4.69 | 4.62 | 4.27 | 4.50 | 4.12 | 4.50 | 4.04 | 4.00 | 3.50 | 4.00 | 3.44 | 3.00 | 2.38 | ||
| 6-1/2 | 5.00 | 4.69 | 5.12 | 4.77 | 4.50 | 4.12 | 4.50 | 4.04 | 4.0 | 3.50 | 4.00 | 3.44 | 4.00 | 3.38 | ||||
| 6-3/4 | 5.50 | 5.19 | 5.12 | 4.77 | 5.25 | 4.86 | 4.50 | 4.04 | 4.00 | 3.50 | 4.00 | 3.44 | 4.00 | 3.38 | ||||
| 7 | 5.50 | 5.19 | 5.62 | 5.27 | 5.25 | 4.86 | 5.25 | 4.80 | 5.00 | 4.50 | 4.00 | 3.44 | 4.00 | 3.38 | ||||
| 7-1/4 | 6.00 | 5.69 | 5.62 | 5.27 | 5.25 | 4.86 | 5.25 | 4.80 | 5.00 | 4.50 | 5.00 | 4.44 | 4.00 | 3.38 | ||||
| 7-1/2 | 6.00 | 5.69 | 6.12 | 5.77 | 6.00 | 5.62 | 5.25 | 4.80 | 5.00 | 4.50 | 5.00 | 4.44 | 5.00 | 4.38 | ||||
| 7-3/4 | 6.12 | 5.77 | 6.00 | 5.62 | 6.00 | 5.54 | 5.00 | 4.50 | 5.00 | 4.44 | 5.00 | 4.38 | ||||||
| 8 | 6.12 | 6.27 | 6.00 | 5.62 | 6.00 | 5.54 | 6.00 | 5.50 | 5.00 | 4.44 | 5.00 | 4.38 | ||||||
Trying to make sense of all the different screw and bolt thread lengths can be a real challenge—even for the most knowledgeable of professionals. Are you finding yourself a little confused, or do you need a quick refresher? Never let thread length get the best of you with our help from ASMC. We’ve put together a handy thread length chart that is certain to make quick work of confusion and increase work production.