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B.S.F SCREW THREADS

Dia of Bolts Threads Per inch Dia. Tap Drill Core Dia   Dia of Bolts Threads Per inch Dia. Tap Drill Core Dia
7/32 28 .1770 .1731   3/4 12 21/32 .6433
1/4 26 .2055 .2007   13/16 12 23/32 .7058
9/32 26 .238 .2320   7/8 11 25/32 .7586
5/16 22 .261 .2543   1 10 57/64 .8719
3/8 20 .316 .3110   1-1/8 9 1 .9827
7/16 18 3/8 .3664   1-1/4 9 1-1/8 1.1077
1/2 16 27/64 .4200   1-3/8 8 1-15/64 1.2149
9/16 16 .492 .4825   1-1/2 8 1.358 1.3399
5/8 14 35/64 .5335   1-5/8 8 1-31/64 1.4649
11/16 14 39/64 .5960    

       

U.N.C Screw Threads

U.N.F. Screw Threads

Dia

(Inch)

NO. OF Threads Core Dia.

(Inch)

Tap Drill   Dia

(Inch)

No. Of Threads Core Dia.

(Inch)

Tap Drill
1/4 20 .1959 5.2 mm   1/4 28 .2113 5.50 mm
5/16 18 .2524 6.60 mm   5/16 24 .2674 6.90 mm
3/8 16 .3073 8.00 mm   3/8 24 .3299 8.50 mm
7/16 14 .3602 9.40 mm   7/16 20 .3834 9.90 mm
1/2 13 .4167 10.80 mm   1/2 20 .4459 11.50 mm
9/16 12 .4723 12.20 mm   9/16 18 .5024 12.90 mm
5/8 11 .5266 13.50 mm   5/8 18 .5649 14.50 mm
3/4 10 .6417 16.50 mm   3/4 16 .6823 11/16 in.
7/8 9 .7547 49/64 mm   7/8 14 .7977 0.804 in
1 8 .8647 22.25 mm   1 12 .9098 23.25 mm
1-1/3 7 .9704 63/64 in.   1-1/8 12 1.0348 26.50 mm
1-1/4 7 1.0954 1-7/64 in.   1-1/4 12 1.1598 29.50 mm
1-3/8 6 1.1946 1-1364 in.   1-3/8 12 1.2848 1.290 in.
1-1/2 6 1.3196 1-21/64 in.   1-1/2 12 1.4098 36.00 mm
1-3/4 5 1.5335 1.35/64 in.          
2 4-1/2 1.7594 1.25.65 mm