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Grade A Square Head Machine Bolts

You can order Grade A Square Head Machine Bolts from Xiaoguo®. We can meet your requirements for length, special threads, and special-shaped square heads. Customized drawings or samples can be provided. The minimum order quantity can be negotiated. We guarantee to provide sample testing within 10 days.

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Product Description

Customized service

The customizable features of the Grade A Square Head Machine Bolts are highly flexible, allowing almost all key parameters to be adjusted as needed to meet your unique application requirements.

（1）Size specification

Thread diameter: Choose according to the load-bearing requirements. It can be provided for applications ranging from small machinery to large-scale engineering.

Screw length: Determined based on the total thickness of the clamped object. Usually, 2-3 pitches will be reserved.

Thread length: Full thread (Fully Threaded) or Partial thread (Partially Threaded)

Thread specifications: UNC, UNF, BSW, ACME, metric coarse thread/finely threaded, etc.

（2）Material selection

Base material: Low carbon steel (such as 1018 / 1022), which is the default choice for cost-effectiveness

Upgrade materials: Medium carbon steel (such as 1035 / 1045), alloy steel (such as 40Cr / 35CrMo), stainless steel (304 / 316), brass, aluminum, etc., to meet the requirements of special working environments

Grade A Square Head Machine Bolt

（3）Mechanical properties

Strength grades: 4.6, 4.8, 5.8, 8.8, 10.9, 12.9, etc. Customization of higher strength grades of Grade A Square Head Machine Bolts are available.

Hardness/ductility: Can be adjusted according to customer requirements through heat treatment (quenching + tempering).

（4）Surface treatment

Basic rust prevention: Black Oxide, Phosphating

Regular rust prevention: Zinc Plated, optional colors such as blue-white, yellow, black, etc.

High-strength rust prevention: Hot-Dip Galvanizing, Dacromet/Geomet

Special properties: Teflon coating, nickel/chromium plating, etc.

（5）Identification and Packaging

Product Identification: Head imprinting / laser marking of brand logo, strength grade, specification size, batch number

Retail Packaging: Colored printed boxes, PE bags with brand labels, etc.

Industrial Packaging: Bulk cartons, woven bags, plastic bags + pallets, etc.

（6）Technical Support

Offer material selection suggestions, torque calculations, installation guidance, and provide a complete service covering the entire process from design selection to actual installation.

Grade A Square Head Machine Bolt

Mon	3/8	7/16	1/2	5/8	3/4	7/8	1	1-1/8	1-1/4	1-3/8	1-1/2
P	16\|24\|32	14\|20\|28	13\|20\|28	11\|18\|24	10\|16\|20	9\|1420	8\|1220	7\|12\|18	7\|12\|18	6\|12\|18	6\|12\|18
ds max	0.388	0.452	0.515	0.642	0.768	0.895	1.022	1.149	1.277	1.404	1.531
s max	0.562	0.625	0.75	0.938	1.125	1.312	1.5	1.688	1875	2.062	2.25
s min	0.544	0.603	0.725	0.906	1.088	1.269	1.45	1.631	1.812	1.994	2.175
e max	0.795	0.884	1.061	1.326	1.591	1.856	2.121	2.386	2.652	2.917	3.182
e min	0.747	0.828	0.995	1.244	1.494	1.742	1.991	2.239	2.489	2.738	2.986
k max	0.268	0.316	0.348	0.444	0.524	0.62	0.684	0.78	0.876	0.94	1.036
k min	0.232	0.278	0.308	0.4	0.476	0.568	0.628	0.72	0.812	0.872	0.964
r max	0.03	0.03	0.03	0.06	0.06	0.06	0.09	0.09	0.09	0.09	0.09
r min	0.01	0.01	0.01	0.02	0.02	0.02	0.03	0.03	0.03	0.03	0.03

Customized Guarantee

The custom service for Grade A Square Head Machine Bolts cover all aspects from basic dimensions to high-end materials, aiming to provide you with the perfect fastener solution.

（1）Standard compliance

For all custom products, unless otherwise specified by the customer, they will be manufactured in accordance with the core standards ASTM A307 (mechanical properties) and ASME B18.2.1 (dimension tolerances), ensuring the universality and reliability of the Grade A Square Head Machine Bolts .

（2）Quality Certification

We have obtained the ISO 9001 quality management system certification, and can provide various industry certifications such as IATF 16949 according to customer requirements.

（3）Traceability system

Each batch of products will retain the entire process of their traceability from the source to the factory.

（4）Flexible minimum order quantity

Standard product: The minimum order quantity is usually 500 - 1,000 pieces.

Customized products: The minimum order quantity is more flexible, ranging from 200 to 500 pieces.

Brand packaging: The minimum order quantity needs to be negotiated with the supplier based on the specific packaging specifications.

（5）Delivery period:

Sample: It can usually be dispatched within 3 to 7 working days.

Batch orders: Typically take 15 to 35 working days, depending on the order quantity and the complexity of customization.