Grade Marked Square Head Bolt

You’ll need an open-end or adjustable wrench to tighten a Grade Marked Square Head Bolt, as its flat sides make it easy to hold, even if the bolt is a bit worn. Xiaoguo® gets its products from good suppliers, so every fastener they send out is strong and meets basic safety rules.

Model:GB/T 8-1988

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Product Description

The Grade Marked Square Head Bolt has a quadrilateral head that is fixed to the threaded rod. Its four corners are sharp and square, which distinguishes it from the hexagonal bolt. The head is usually larger than the threaded part, so it can disperse the pressure when being tightened - this helps prevent material damage. Most of the bolt body has threads, so it can be screwed into a pre-drilled nut or hole. Some of these bolts have a flat bottom head, while others are slightly conical. This makes it easier to align and start the tightening process. Due to its smooth sides, this type of bolt is very practical in narrow spaces, as it can still function properly in such locations even when a regular wrench might slip at the circular head.

Excellent rust resistance

The color of the Grade Marked Square Head Bolt depends on the type of coating on their surface. The pure steel bolts are dark gray and are suitable for dry internal environments. If they are coated with a black oxide layer, they will have a dark gray or nearly black appearance. This coating combines anti-rust protection with low light reflection properties, which is a significant advantage for machine use scenarios such as garages and wet work areas where glare is likely to occur. Galvanized bolts have a shiny silver appearance, sometimes with a hint of yellow. They are better able to withstand humid environments - such as garages or damp workspaces. If the product is often used outdoors and may face harsh weather conditions such as rain and snow, then hot-dip galvanized bolts will be the best adaptation solution. They have a rough matte gray surface and can withstand harsh weather conditions.

Mon	1-1/4	1-3/8	1-1/2	1-5/8	1-3/4	2	2-1/4	2-1/2	2-3/4	3	3-1/4
P	7	-	6	5	5	4.5	4	4	3.5	3.5	3.25
ds max	1.3	1.425	1.55	1.685	1.81	2.06	2.25	2.5	2.5	3	3.25
k max	0.89	0.98	1.06	1.18	1.27	1.43	1.6	1.77	1.93	2.15	2.32
k min	0.83	0.92	1	1.08	1.17	1.33	1.5	1.67	1.83	2	2.17
s max	1.86	2.05	2.22	2.41	2.58	2.76	3.15	3.55	3.89	4.18	4.53
s min	1.815	2.005	2.175	2.365	2.52	2.7	3.09	3.49	3.83	4.08	4.43
r max	0.125	0.125	0.125	0.125	0.125	0.125	0.1875	0.1875	0.1875	0.1875	0.25

FAQ

Q: Which international standards do your Grade Marked Square Head Bolt conform to?

A: The standard Grade Marked Square Head Bolt we produce mainly follow the ANSI B18.2.1 standard. This standard specifies the size specifications for square and hexagonal bolts in imperial units. We can also produce square-head bolt products according to other specifications based on your technical drawings. Please clearly define the standards you require, as this ensures that the products are compatible with your specific application and market, and possess good mechanical properties.

Grade Marked Square Head Bolt