MPA & Tensile Strengths.

Grade 2

Cap Screw Diameter Course Thread Fine Thread
Threads Per Inch Tensile Strength Min. Lb. Proof Load Min. Lb. Threads Per Inch Tensile Strength Min. Lb. Proof Load Min. Lb.
1/4″ 20 2350 1750 28 2700 2000
5/16″ 18 3900 2900 24 4300 3200
3/8″ 16 5750 4250 24 6500 4800
7/16″ 14 7850 5850 20 8800 6550
1/2″ 13 10500 7800 20 11800 8800
9/16″ 12 13500 10000 18 15000 11200
5/8″ 11 16700 12400 18 18900 14100
3/4″ 10 24700 18400 16 27600 20500
7/8″ 9 27700 15200 14 30500 16800
1″ 8 26400 20000 12 39800 21900
1 1/8″ 7 45800 25200 12 51400 28200
1 1/4″ 7 58100 32000 12 64400 35400
1 1/2″ 6 84300 46400 12 94900 52200

Grade 5

Cap Screw Diameter Course Thread Fine Thread
Threads Per Inch Tensile Strength Min. Lb. Proof Load Min. Lb. Threads Per Inch Tensile Strength Min. Lb. Proof Load Min. Lb.
1/4″ 20 3800 2700 28 4350 3100
5/16″ 18 6300 4450 24 6950 4900
3/8″ 16 9300 6600 24 105050 7450
7/16″ 14 12800 9050 20 14200 10100
1/2″ 13 17000 12100 20 19200 13600
9/16″ 12 21800 15500 18 24400 17300
5/8″ 11 27100 19200 18 30700 21800
3/4″ 10 40100 28400 16 44800 31700
7/8″ 9 55400 39300 14 61100 43300
1″ 8 72700 51500 12 79600 56400
1 1/8″ 7 80100 56500 12 89900 63300
1 1/4″ 7 101700 71700 12 112700 79400
1 1/2″ 6 147500 104000 12 166000 117000

Grade 8

Cap

Screw

Diameter

 Course Thread Fine Thread
Threads

Per

Inch

 Tensile

Strength

Min. Lb.

 Proof

Load

Min. Lb.

 Threads

Per

Inch

 Tensile

Strength

Min. Lb.

 Proof

Load

Min. Lb.
1/4″ 20 4750 3800 28 5450 4350
5/16″ 18 7850 6300 24 8700 6950
3/8″ 16 11600 9300 24 13200 10500
7/16″ 14 15900 12800 20 17800 14200
1/2″ 13 21300 17000 20 24000 19200
9/16″ 12 27300 21800 18 30400 24400
5/8″ 11 33900 27100 18 38400 30700
3/4″ 10 50100 40100 16 56000 44800
7/8″ 9 69300 55400 14 76400 61100
1″ 8 90900 72700 12 99400 79600
1 1/8″ 7 114400 91600 12 128400 102700
1 1/4″ 7 145400 116300 12 161000 128800
1 1/2″ 6 210800 168600 12 237200 189700