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Socket Head Cap Screw Thread Lengths

socket-head-cap-screw-thread-lengths.jpg

Nom. Size D#0#1#2#3#4#5#6#8#10
Basic Thread Length
LT
0.5000.6250.6250.6250.7500.7500.7500.8750.875
Nominal Length LLGLBLGLBLGLBLGLBLGLBLGLBLGLBLGLBLGLB
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 D1/45/163/87/161/25/83/47/81.000
Basic Thread Length LT1.0001.1251.2501.3751.5001.7502.0002.2502.500
Nominal Length LLGLBLGLBLGLBLGLBLGLBLGLBLGLBLGLBLGLB
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 bold 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.