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JM Hardware Carriage Bolt - Anti-Turn Square Shoulder, Hex Cap Screw
JM Hardware Carriage Bolt - Anti-Turn Square Shoulder, Hex Cap Screw is a strong fastener that stays put while you tighten it. The square shoulder bites into the hole to stop the bolt from turning, and the hex head fits a wrench for quick tightening. It’s great for simple, one-side installs in wood or metal.
Usage scenarios:
- Join deck boards, fence posts, or gates where the bolt must not spin during tightening.
- Fasten metal frames, machinery parts, or brackets when you only have access to one side.
- Build furniture, playgrounds, or farm gear that need a neat, strong hold.
Usage scenarios:
- Join deck boards, fence posts, or gates where the bolt must not spin during tightening.
- Fasten metal frames, machinery parts, or brackets when you only have access to one side.
- Build furniture, playgrounds, or farm gear that need a neat, strong hold.
Product features
The JM Hardware carriage bolt with an anti-turn square shoulder features a smooth round head, flat tip and partially threaded shank that grips wood while the square shoulder locks into the material to prevent rotation — unlike a hex cap screw, which relies on a wrenched hex head, this design provides a flush, tamper‑resistant finish for timber and panel assemblies. Available in sizes from 1/4"–1" and M6–M30 and manufactured in carbon and stainless steels with grades from A307/A2–A4 through 8.8/10.9/12.9 plus multiple finishes (plain, zinc, black oxide, nickel, chrome, HDG), the bolt delivers high tensile strength and corrosion resistance for demanding structural and outdoor applications. JM Hardware’s ISO 9001‑aligned production combines automated cold headers, thread rolling, heat treatment and comprehensive testing (Rockwell, tensile, magnetic particle, SGS) with certified packing and export documentation, ensuring consistent quality, traceability and supply‑chain value for contractors and distributors.
Team strength
JM Hardware's team blends engineering precision and production strength to deliver carriage bolts with anti-turn square shoulders and hex cap heads. Our skilled engineers optimize material selection, heat treatment, and dimensional control while production teams maintain consistent thread quality and finishes. Dedicated quality inspectors run batch testing, torque and fatigue checks, and certification handling to ensure reliability. Supply-chain coordinators guarantee on-time deliveries and scalable volumes, while customer service and technical support provide fast custom solutions and installation guidance. This cohesive team approach ensures every bolt meets performance specs, reduces assembly downtime, and provides long-term value to manufacturers, builders, and distributors.
Enterprise core strength
JM Hardware’s dedicated team combines engineering precision, skilled machining, and rigorous quality control to deliver carriage bolts with anti‑turn square shoulders and hex cap heads. Core strengths include materials expertise, tight-tolerance production, and certified inspection processes that ensure consistent fit and durability. Value-driven support spans rapid quoting, customized sizing, and volume manufacturing capacity to meet project timelines. Cross-functional collaboration between R&D, supply chain, and customer service accelerates problem-solving and continuous improvement. The result is dependable fasteners, transparent communication, and scalability—giving customers confidence in performance, supply reliability, and long-term partnerships for construction and industrial applications, including worldwide delivery and technical training.
Product Introduction
A carriage bolt is a type of fastener that can be made from a number of different materials (stainless steel being the most popular). A carriage bolt generally has a round head and a flat tip and is threaded along part of its shank. Carriage bolts are often referred to as plow bolts or coach bolts and are most commonly used in wood applications. However, they are much more diverse than people might think.
Product Parameters
Carriage bolt | |
Size: | 1/4”-1”,M6-M30 |
Material: | Carbon Steel |
Grade: | A307 Gr. A; SAE J429 Gr.2, 5,8 Class: 8.8, 10.9, 12.9 A2-70, A2-80, A4-70, A4-80 (Stainless Steel) |
Finish: | Plain, Zinc Plated(Clear/Blue/Yellow/Black), Black oxide, Nickel, Chrome, H.D.G. |
Product Details
Quality Control
JM Hardware conducts product quality control in strict accordance with ISO 9001 standards to ensure that our products meet high quality standards. Below are our five quality control steps:
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Incoming material control
We carry out strict incoming material control by conducting dimensional tests on each batch of raw materials and checking the raw material reports from the steel mills. This ensures that the raw materials we use are within specification and provide a reliable basis for production.
We carry out strict incoming material control by conducting dimensional tests on each batch of raw materials and checking the raw material reports from the steel mills. This ensures that the raw materials we use are within specification and provide a reliable basis for production.
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First part control
After the mold assembly is completed, we conduct a thorough inspection of the first production part and make detailed records. Only qualified first parts can be released to start mass production. This step ensures that the quality of the product meets the standard at the beginning.
After the mold assembly is completed, we conduct a thorough inspection of the first production part and make detailed records. Only qualified first parts can be released to start mass production. This step ensures that the quality of the product meets the standard at the beginning.
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Self-inspection by workers during mass production
In the mass production process, we require the workers of each machine to carry out self-inspection every hour. If any substandard product is found, we will immediately pick or scrap the production within this hour until the problem is solved and meets the standard of conformity, and then we can continue the production. This self-inspection mechanism helps to find and solve problems in time during the production process.
In the mass production process, we require the workers of each machine to carry out self-inspection every hour. If any substandard product is found, we will immediately pick or scrap the production within this hour until the problem is solved and meets the standard of conformity, and then we can continue the production. This self-inspection mechanism helps to find and solve problems in time during the production process.
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QC inspection during mass production
In addition, every two hours, the quality inspection personnel will carry out random inspection on the products of each machine. Only qualified products can continue to flow into the next production stage. If non-conforming products are found, we will take the same selection or scrapping measures and ensure that the problem is properly handled. This helps provide additional quality assurance.
In addition, every two hours, the quality inspection personnel will carry out random inspection on the products of each machine. Only qualified products can continue to flow into the next production stage. If non-conforming products are found, we will take the same selection or scrapping measures and ensure that the problem is properly handled. This helps provide additional quality assurance.
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Finished product control
Finally, after each batch of finished product is made, we conduct random inspections in proportion to the order. Qualified products will be packaged and put into storage, while unqualified products will be returned for further analysis and rectification. We insist on ensuring that the quality of our products meets high standards so that we can provide reliable products to our customers.
Finally, after each batch of finished product is made, we conduct random inspections in proportion to the order. Qualified products will be packaged and put into storage, while unqualified products will be returned for further analysis and rectification. We insist on ensuring that the quality of our products meets high standards so that we can provide reliable products to our customers.
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Non-conforming goods management
According to the process of JMhardware's non-conforming products handling, pick or scrap. And the problem of rectification and tracking reasons to ensure that non-conforming products will not flow into the market.
According to the process of JMhardware's non-conforming products handling, pick or scrap. And the problem of rectification and tracking reasons to ensure that non-conforming products will not flow into the market.
These quality control measures constitute JM Hardware's quality management system, and we are constantly striving to improve the quality of our products and are committed to meeting the needs of our customers. We believe that quality control is the key to our success.
Production equipment
Testing Equipment
Magnetic particle flaw detectorTest report
SGS testing report --310S bolt nut
Third-party testing report-P1
Third-party testing report-P2
JM Hardware® testing report
Packing
Why Choose Us
Strong R&D Capability
Successfully developed 680+ new products in past 16 years
Rich Industry Experience
JM has the rich experience to supply the high quality fasteners to Project contractor
Mature & professional service teams
Provides 24/7 online and offline services for you,70%stuff have 5+ working experience in JM
Rich export experience
15+ years exported to 70+ countries
Supply one-stop service & DDP term
Help clients purchase other products,realize door-to-door service to make international procurement more convenient
Certificate
Valued Partners
JM Hardware @ has exported its hardware parts to over 85 countries around the world.
We will make unremitting efforts to provide hardware parts with high quality and reasonable prices for our customers.
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Contact us
we welcome custom designs and ideas and is able to cater to the specific requirements. for more information, please visit the website or contact us directly with questions or inquiries.
xarella.huang@jm-fastener.comOur address
Add: Rm.27202, No.295 South Lingyan Road, Pudong,Shanghai,P.R.C
Contact person: xarella.huang
Whatsapp: +86 13681923533
Wechat:+86 18621005605
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Since our establishment in 2006, JM has been adhering to the mission of creating maximum value for customers by providing differentiated services, and making a positive contribution to the society.