Custom Square Head Bolts

Square Head bolts, square bolts, also called machine bolts are threaded to receive a nut, These bolts have large, flat sides and are easy to tighten with a wrench, come in smooth, hammered, and pyramid head styles. Square Head Bolts are similar to Hex Cap screws but have a 4-sided square head instead of a 6-sided hexagonal head.

Square bolts are now most commonly used for aesthetic purposes to provide a rustic look in a new structure or to match existing fasteners in an older structure. Square lag screws are also used for these purposes. Crossarm or machine bolts are commonly supplied for the utility industry and included an added cone point. Square heads are also best used in tight or dark spaces where a machinist or fabricator must tighten the bolt blind. It is simple to fit a tool over the square shape even when there are no visual markers available.

DIN 21346 – 1989 Square Head Bolts Dimensions Sizes

Screw Thread(d)	M16	M20	M24	M30
P Pitch	2	2.5	3	3.5
b L≤200	36	43	53	–
L＞200	48	58	73	82
e	38.2	45.3	58	70.7
k	10	13	15	19
s	27	32	41	50

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