Square Head Set Screw
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Square Head Set Screw

Square head set screws, also known as jack bolts, are fully threaded fasteners with a square head and most commonly, a cup point, though other types of points are available. Square head set screws are manufactured from alloy steel for maximum strength, as well as high resistance to galling , wear, and fatigue. They have a large wrenching area that provides positive gripping for a hand wrench. They are ideal for holding pulleys, collars, and other machinery shafts where fine adjustments are necessary. Dimensional specifications are governed by ASME B18.6.2.

Governing StandardsAlloy Steel Square Head Set Screw

ASME B18.6.2 Covers the complete general and dimensional data for the various styles of slotted head cap screws and square head and slotted headless set screws recognized as American National Standard.
ASME B1.1 UNC & UNF Class 2A Specifies the thread form, series, class, allowance, tolerance, and designation for unified screw threads.

Alloy Steel Square Head Set Screw
Alloy Steel Square Head Set Screw requires no material marking

Dimensional SpecificationsAlloy Steel Square Head Set Screw

Finished bolt and cap screw dimensions
Per ASME B18.6.2-1998
Size Nominal UNC UNF F G H K S U W
Width Across
Flats
Width Across
Corners
Head
Height
Neck Relief
Diameter
Neck
Relief
Fillet
Radius
Neck
Relief
Width
Head
Radius
Max Min Max Min Max Min Max Min Max Min Min
#10 0.1900 24 32 0.1880 0.1800 0.2650 0.2470 0.1480 0.1340 0.1450 0.1400 0.0270 0.0830 0.4800
1/4 0.2500 20 28 0.2500 0.2410 0.3540 0.3310 0.1960 0.1780 0.1850 0.1700 0.0320 0.1000 0.6200
5/16 0.3125 18 24 0.3120 0.3020 0.4420 0.4150 0.2450 0.2240 0.2400 0.2250 0.0360 0.1110 0.7800
3/8 0.3750 16 24 0.3750 0.3620 0.5300 0.4970 0.2930 0.2700 0.2940 0.2790 0.0410 0.1250 0.9400
7/16 0.4375 14 20 0.4380 0.4230 0.6190 0.5810 0.3410 0.3150 0.3450 0.3300 0.0460 0.1430 1.0900
1/2 0.5000 13 20 0.5000 0.4840 0.7070 0.6650 0.3890 0.3610 0.4000 0.3850 0.0500 0.1540 1.2500
9/16 0.5625 12 18 0.5620 0.5450 0.7950 0.7480 0.4370 0.4070 0.4540 0.4390 0.0540 0.1670 1.4100
5/8 0.6250 11 18 0.6250 0.6060 0.8840 0.8330 0.4850 0.4520 0.5070 0.4920 0.0590 0.1820 1.5600
3/4 0.7500 10 16 0.7500 0.7290 1.0600 1.0010 0.5820 0.5440 0.6200 0.6050 0.0650 0.2000 1.8800
7/8 0.8750 9 14 0.8750 0.8520 1.2370 1.1700 0.6780 0.6350 0.7310 0.7160 0.0720 0.2220 2.1900
1 1.0000 8 14 1.0000 0.9740 1.4140 1.3370 0.7740 0.7260 0.8380 0.8230 0.0810 0.2500 2.5000
1 1/8 1.1250 7 12 1.1250 1.0960 1.5910 1.5050 0.8700 0.8170 0.9390 0.9140 0.0920 0.2830 2.8100
1 1/4 1.2500 7 12 1.2500 1.2190 1.7680 1.6740 0.9660 0.9080 1.0640 1.0390 0.0920 0.2830 3.1200
1 3/8 1.3750 6 12 1.3750 1.3420 1.9450 1.8430 1.0630 1.0000 1.1590 1.1340 0.1090 0.3330 3.4400
1 1/2 1.5000 6 12 1.5000 1.4640 2.121 2.0100 1.1590 1.0910 1.2840 1.2590 0.1090 0.3330 3.7500
  1. All dimensions are in inches.
Square Head Set Screw
View
Diameter Thread Pitch Length Threading Item # Availability Price Quantity UOM
1/4 20 1/2 Full SHSA0250050 In Stock $0.09249/EA EA
1/4 20 3/4 Full SHSA0250075 In Stock $0.11099/EA EA
1/4 20 1 Full SHSA0250100 In Stock $0.11791/EA EA
1/4 20 1 1/4 Full SHSA0250125 In Stock $0.16582/EA EA
1/4 20 1 1/2 Full SHSA0250150 In Stock $0.16859/EA EA
1/4 20 2 Full SHSA0250200 In Stock $0.30884/EA EA
1/4 20 4 Full SHSA0250400 In Stock $3.58861/EA EA
1/4 20 4 1/2 Full SHSA0250450 In Stock $3.47351/EA EA
1/4 20 6 Full SHSA0250600 3-5 Working Days $3.47351/EA EA
5/16 18 1/2 Full SHSA0310050 In Stock $0.18572/EA EA
5/16 18 3/4 Full SHSA0310075 In Stock $0.22679/EA EA
5/16 18 1 Full SHSA0310100 In Stock $0.19959/EA EA
5/16 18 1 1/4 Full SHSA0310125 In Stock $0.29382/EA EA
5/16 18 1 1/2 Full SHSA0310150 In Stock $0.35764/EA EA
5/16 18 2 Full SHSA0310200 In Stock $0.33629/EA EA
5/16 18 3 Full SHSA0310300 In Stock $1.43622/EA EA
3/8 16 1/4 Full SHSA0370025 3-5 Working Days $0.22198/EA EA
3/8 16 1/2 Full SHSA0370050 In Stock $0.3778/EA EA
3/8 16 3/4 Full SHSA0370075 In Stock $0.33215/EA EA
3/8 16 1 Full SHSA0370100 In Stock $0.33115/EA EA
3/8 16 1 1/2 Full SHSA0370150 In Stock $0.4488/EA EA
3/8 16 2 Full SHSA0370200 In Stock $0.62168/EA EA
3/8 16 2 1/2 Full SHSA0370250 In Stock $0.70137/EA EA
3/8 16 3 Full SHSA0370300 In Stock $1.1232/EA EA
3/8 16 4 Full SHSA0370400 In Stock $1.45257/EA EA
3/8 16 5 Full SHSA0370500 In Stock $1.83811/EA EA
3/8 16 6 Full SHSA0370600 In Stock $6.66763/EA EA
7/16 14 3/4 Full SHSA0430075 3-5 Working Days $0.84994/EA EA
7/16 14 1 Full SHSA0430100 In Stock $1.05142/EA EA
7/16 14 1 1/2 Full SHSA0430150 In Stock $0.87643/EA EA
7/16 14 2 Full SHSA0430200 In Stock $0.94462/EA EA
7/16 14 2 1/2 Full SHSA0430250 In Stock $0.70292/EA EA
1/2 13 3/4 Full SHSA0500075 In Stock $0.55808/EA EA
1/2 13 1 Full SHSA0500100 In Stock $1.17999/EA EA
1/2 13 1 1/4 Full SHSA0500125 In Stock $0.99834/EA EA
1/2 13 1 1/2 Full SHSA0500150 In Stock $1.31731/EA EA
1/2 13 2 Full SHSA0500200 In Stock $1.74835/EA EA
1/2 13 2 1/2 Full SHSA0500250 In Stock $1.27636/EA EA
1/2 13 3 Full SHSA0500300 In Stock $2.20266/EA EA
1/2 13 3 1/2 Full SHSA0500350 In Stock $2.14706/EA EA
1/2 13 4 Full SHSA0500400 In Stock $2.34924/EA EA
1/2 13 4 1/2 Full SHSA0500450 In Stock $4.14262/EA EA
1/2 13 5 Full SHSA0500500 In Stock $2.57407/EA EA
1/2 13 6 Full SHSA0500600 In Stock $3.54717/EA EA
1/2 13 8 Full SHSA0500800 In Stock $9.17921/EA EA
1/2 13 10 Full SHSA0501000 In Stock $20.18128/EA EA
5/8 11 3/4 Full SHSA0620075 3-5 Working Days $1.80984/EA EA
5/8 11 1 Full SHSA0620100 In Stock $1.10326/EA EA
5/8 11 1 1/4 Full SHSA0620125 In Stock $1.80984/EA EA
5/8 11 1 1/2 Full SHSA0620150 In Stock $1.59042/EA EA
5/8 11 2 Full SHSA0620200 In Stock $1.80155/EA EA
5/8 11 2 1/2 Full SHSA0620250 In Stock $2.53899/EA EA
5/8 11 3 Full SHSA0620300 In Stock $3.22449/EA EA
5/8 11 3 1/2 Full SHSA0620350 In Stock $2.88468/EA EA
5/8 11 4 Full SHSA0620400 In Stock $4.65383/EA EA
5/8 11 4 1/2 Full SHSA0620450 In Stock $5.58639/EA EA
5/8 11 5 Full SHSA0620500 In Stock $6.28657/EA EA
5/8 11 6 Full SHSA0620600 In Stock $5.7495/EA EA
5/8 11 8 Full SHSA0620800 3-5 Working Days $12.78661/EA EA
3/4 10 1 Full SHSA0750100 In Stock $1.36885/EA EA
3/4 10 2 Full SHSA0750200 In Stock $3.27954/EA EA
3/4 10 2 1/2 Full SHSA0750250 In Stock $4.93611/EA EA
3/4 10 3 Full SHSA0750300 In Stock $5.89501/EA EA
3/4 10 3 1/2 Full SHSA0750350 In Stock $4.98324/EA EA
3/4 10 4 Full SHSA0750400 In Stock $4.84539/EA EA
3/4 10 4 1/2 Full SHSA0750450 In Stock $7.76652/EA EA
3/4 10 5 Full SHSA0750500 In Stock $6.80163/EA EA
3/4 10 5 1/2 Full SHSA0750550 In Stock $9.60337/EA EA
3/4 10 6 Full SHSA0750600 In Stock $7.98479/EA EA
3/4 10 6 1/2 Full SHSA0750650 3-5 Working Days $6.58938/EA EA
7/8 9 2 Full SHSA0870200 In Stock $2.7007/EA EA
7/8 9 2 1/2 Full SHSA0870250 In Stock $3.25564/EA EA
7/8 9 3 Full SHSA0870300 In Stock $5.67425/EA EA
7/8 9 4 Full SHSA0870400 In Stock $6.32815/EA EA
7/8 9 5 Full SHSA0870500 In Stock $12.06478/EA EA
7/8 9 6 Full SHSA0870600 In Stock $12.34898/EA EA
7/8 9 8 Full SHSA0870800 In Stock $30.59741/EA EA
7/8 9 10 Full SHSA0871000 In Stock $26.67407/EA EA
1 8 2 Full SHSA1000200 In Stock $8.80503/EA EA
1 8 3 Full SHSA1000300 In Stock $6.5899/EA EA
1 8 4 Full SHSA1000400 In Stock $12.23892/EA EA
1 8 5 Full SHSA1000500 In Stock $10.07751/EA EA
1 8 5 1/2 Full SHSA1000550 In Stock $32.5256/EA EA
1 8 6 Full SHSA1000600 In Stock $12.88154/EA EA
1 8 7 Full SHSA1000700 In Stock $29.32619/EA EA
1 8 8 Full SHSA1000800 3-5 Working Days $31.57603/EA EA