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Socket head screws, also known as Allen screws, are indispensable fasteners for a wide range of applications, from furniture assembly to machinery repair. Their hexagonal socket drive allows for high torque application and a clean, flush finish. Selecting the correct type and size ensures secure connections and prevents damage to both the screw and the equipment.
【Perfect for DIY Projects】 This M3 screw assortment kit are ideal for hobbyists working with 3D printing, electronics, RC models, DIY repairs, chair replacement and CNC machinery, offering precision for intricate designs.
【Standardized Metric Sizes】 -The M3-0.5 hex socket head cap screws set come with 8 commonly used lengths—M3 x 6mm, 8mm, 10mm, 12mm, 16mm,20mm,25mm,30mm—ideal for routine installations and repairs. They meet standard metric specs, the average error...
【Premium 12.9 Grade Alloy Steel】- This M3 bolts, nuts and washers assorted kit are crafted from high-strength 12.9 grade alloy steel, ensuring exceptional durability and load-bearing capacity. High-strength steel resists wear, corrosion, and heavy...
【Oil-Free & Rust-Proof】 -Black zinc plating means no greasy mess—keep hands and projects clean. Superior rust resistance ensuring long life.This 3mm black allen screw set perfect for any indoor/light outdoor use.
【Smart Storage Box 】- The metric machine screws kit comes in a durable, compartmentalized case with clear size labels—so you can spot the right screw instantly. Keeps your workspace tidy and speeds up project progress, making every job smoother.
【4 Sizes Metric Screw Set】This 1760pcs screws kit includes M2-0.4, M3-0.5, M4-0.7, M5-0.8 sizes with precise thread diameters (2mm/3mm/4mm/5mm) and Lenths of the bolts M3x6mm/8mm/10mm/12mm, M4x8mm/10mm/16mm/20mm, M5x10mm/16mm/20mm/30mm...
【Perfect for DIY Projects】 This hex socket head screw assorted kit are ideal for hobbyists working with 3D printing, electronics, RC models, DIY repairs, chair replacement and CNC machinery, offering precision for intricate designs.
【Premium 12.9 Grade Alloy Steel】- This machine screw assortment kit are crafted from high-strength 12.9 grade alloy steel, ensuring exceptional durability and load-bearing capacity. High-strength steel resists wear, corrosion, and heavy loads, ideal...
【Organized Storage Box 】- The M2 M3 M4 M5 allen head screws set comes in a compartmentalized case with clear labels for quick access to bolts, washers, and nuts. Keeps your workspace tidy and speeds up project progress, making every job smoother.
【Wide Applications】Keep a set of commonly used Fgruh metric hardware assortment at hand. Whether you are working on DIY projects, bicycle repairs, or professional construction, it can meet your needs at any time, making your work more convenient and...
【4 Sizes Metric Screw Assortment Kit】This 2200pcs screws set includes M2-0.4, M3-0.5, M4-0.7, M5-0.8 sizes with precise thread diameters (2mm/3mm/4mm/5mm). Lenths of the thread M2x4mm/8mm/12mm/16mm. M3x6mm/8mm/12mm/16mm. M4x8mm/12mm/16mm/20mm...
【High quality】– Made of durable 10.9 grade alloy steel metric bolts, nuts and washers assorted kit with oil-free black galvanizing for corrosion resistance. Smooth, burr-free surface with precise threading ensures secure fastening. Weatherproof...
【Organized & Portable】The hex socket button head bolt assortment sets are neatly packed in a sturdy plastic storage box, ensuring easy organization and quick access. The metric machine assortment kit includes M2 M3 M4 M5 sizes for convenient...
【Wide Applications】Keep a set of commonly used small screw hardware kit at hand. Whether you are working on DIY projects, small projects repair, or professional construction, it can meet your needs at any time, making your work more convenient and...
【Brand Guarantee】 Backed by rigorous quality control, Fgruh guarantees reliable metric screw for your projects. Enjoy peace of mind with our 24-month warranty and dedicated customer support.
【4 Sizes Metric Screw Set】This 1220pcs screws kit includes M3, M4, M5,M6 sizes with precise thread diameters (3mm/4mm/5mm/6mm) and Lenths of the bolts M3-0.5x6mm/8mm/10mm/12mm, M4-0.7x8mm/10mm/16mm/20mm, M5-0.8x10mm/16mm/20mm/30mm...
【Perfect for DIY Projects】 This hex socket head screw assorted kit are ideal for hobbyists working with 3D printing, electronics, RC models, DIY repairs, chair replacement and CNC machinery, offering precision for intricate designs.
【304 Stainless Steel Material 】 This metric cap head bolts,nuts and washers assortment kit are made of high-quality 304 stainless steel, which resist corrosion and rust, with smooth threads and high hardness for secure fastening, heavy-load capacity...
【Organized Storage Box 】- The M3 M4 M5 M6 allen head screws set comes in a compartmentalized case with clear labels for quick access to bolts, washers, and nuts. Keeps your workspace tidy and speeds up project progress, making every job smoother.
【Wide Applications】Keep a set of commonly used Fgruh metric hardware assortment at hand. Whether you are working on DIY projects, bicycle repairs, or professional construction, it can meet your needs at any time, making your work more convenient and...
【SMALL PRECISION SCREWS – IDEAL FOR 3D PRINTING & DIY】 Includes M2 / M3 / M4 / M5 metric screws, specially designed for 3D printing, electronics repair, RC models, and precision DIY projects. ⚠️ These are small-size screws, NOT suitable for...
【WIDE SIZE COVERAGE – MOST COMMON SIZES IN ONE KIT】 Covers the most frequently used metric sizes: M2 (4/8/12/16mm), M3 (6/8/12/16mm), M4 & M5 (8/12/16/20mm) with standard ISO/DIN threads. One complete kit eliminates repeated purchases and ensures...
【MOST FREQUENTLY USED SIZES FOR 3D PRINTING & DIY】 This kit includes M2, M3, M4, and M5 — the most commonly used metric screw sizes for 3D printing, robotics, RC models, and precision DIY projects. With a balanced 1:1 ratio of screws, nuts, washers...
【CLEARLY ORGANIZED BOX + SIZE LABELS + INCLUDED WRENCHES】 All parts are stored in a durable, compartmentalized case with clear, easy-to-read labels for quick identification. Includes M2–M5 hex keys (Allen wrenches), making installation faster and...
【10.9 GRADE ALLOY STEEL – DURABLE & PRECISE THREADS】 Made from high-strength 10.9 grade alloy steel, featuring clean threads, excellent durability, and reliable fastening performance. Backed by Kadrick’s strict quality control and a 24-month...
Thread: Coarse / Full Thread / Alloy Steel / Black Oxide
Recommended Hex Socket Allen Key Wrench: 3/16
Black Oxide is not a protective finish and will rust if exposed to moisture.
Fits all common climbing holds: Our climbing bolts will fit in all standard climbing holds on the market today. We offer different length packs to have you covered in all aspects
Stainless Steel material is recommended for environments with moisture
✔ Includes 500 Pcs, 13 Sizes, M3 Hex Socket Head Cap Screws, Screws Head Style: Socket Cap Head, Screws Drive Style: Hex Socket Drive ( Hex Size 2.5 mm ), Thread Pitch 0.5 mm, Thread Size ( Diameter ) 3 mm, Thread Length From 4 mm to 50 mm: M3 x 4, M3 x...
✔ Includes 500 Pcs Thread Pitch 0.5 mm M3 Hex Nuts to Meet Different Applications;These Hex Nuts are Made of Made of Stainless Steel 304 and Not Need Additional Finish,High Strength and Anti-corrosion in Various Conditions.
✔ Includes 500 Pcs Φ3 Washers: Add More Touch Area to Meet Different Applications, Protect Parts from Being Damaged;These Washers are Made of Made of Stainless Steel 304 and Not Need Additional Finish,High Strength and Anti-corrosion in Various...
✔ Includes 1 Pcs Hex Key, Hex Size: 2.5 mm, to Drive These Screws Conveniently and Easily; This Hex Key is Made of Chrome-Vanadium Steel and Nickel Plated, Higher Strength and Anti-rust
【 Organized and Packed Well 】 These 500 Pcs Screws, 500 Pcs Hex Nuts, 500 Pcs Washers and 1 Pcs Hex Key Packed in a Sturdy Multi-compartments Plastic Organizer Box , Organized Conveniently and Easily【 About Hex Socket Drive 】 Hex Socket Drive...
Exquisite Material: These allen head wood screws are made of high-quality stainless steel with high strength and hardness, corrosion and rust resistance, smooth surface without burrs, not easy to break or deform, durable for use.
Cylinder Cup Head & Hex Socket Cap Design: The thread of metric socket head cap screw assortment is clear and firm, smooth and burr-free, easy to insert and not easy to loosen. The design of the inner hex head also makes it easy to install.
Easy to Store: All hex cap self tapping screws are stored in a clear and sturdy storage box with compartments. The socket head cap screw assortment is stored separately, well-organized, easy to carry and find. Mess-free and easy to use during transport.
Wide Application: Suitable for assembling most beds, tables, chairs, workbenches, etc., for joining most woods, planks, kitchen countertops, cabinets, etc. Also commonly used in furniture, machinery, automobiles, motorcycles, auto repair and DIY...
Package Includes: You will receive 480 pcs in total, sizes include 80 pcs m3x6mm, 70 pcs m3x8mm, 65 pcs 3x10mm, 55 pcs m3x12mm, 50 pcs m3x14mm, 35 pcs m3x16mm, 35 pcs m3x18mm, 30 pcs m3x20mm, 30 pcs m3x25mm, 30 pcs m3x30mm , the quantity is sufficient...
【Product Details】- This M5 screw assortment kit comes with a total of 272 pieces, includes 72pcs hex socket head bolts,40pcs hex nuts, 80pcs flat washers, 80pcs spring washers, and a mini wrench.The m5 metric socket head cap screw kit feature...
【High Quality】– Made of durable 12.9 alloy steel 5mm black hardware kit with oil-free black galvanizing for corrosion resistance. Smooth, burr-free surface with precise threading ensures secure fastening. Good rust resistance for indoor/light...
【Wide Applications】This M5 hex socket head bolts assorted kit is perfect for all sorts of building and repair projects. Whether you’re into 3D printing, working on RC cars, fixing small electronics, or tackling DIY jobs—these screws have you...
【Organized Storage Box 】- The M5 machine screw set comes in a durable, compartmentalized case with clear size labels—so you can spot the right screw instantly. Keeps your workspace tidy and speeds up project progress, making every job smoother.
【Brand Guarantee】 Backed by rigorous quality control, Fgruh guarantees reliable metric screw for your projects. Enjoy peace of mind with our 24-month warranty and dedicated customer support.
This article is part of our complete guide Hand Tools — browse all our comparisons and buying guides.
Last update on 2026-07-11 / Affiliate links / Images from Amazon Product Advertising API
How to Choose the Best Socket Head Screws
Understanding Socket Head Screw Types
Cap Screws (Socket Head Cap Screws): These are the most common type, featuring a cylindrical head with a hexagonal socket. They are ideal for applications requiring strength and a flush or countersunk finish.
Set Screws (Socket Set Screws): These screws lack a head and are designed to secure an object within or against another object. They are often used to prevent relative motion between parts, like fastening a pulley to a shaft.
Button Head Screws: With a low-profile, rounded head, these offer a clean aesthetic and are suitable for areas where a protruding head is undesirable.
Flat Head Screws: These have a countersunk head that sits flush with the surface, providing a smooth finish. They are often used in conjunction with a countersunk hole.
Material Matters
Stainless Steel: Offers excellent corrosion resistance, making it suitable for outdoor or wet environments. Grades like 18-8 (304) and 316 provide varying levels of strength and resistance.
Alloy Steel: Typically heat-treated for high strength and durability, often coated with black oxide for moderate corrosion resistance and a sleek appearance.
Brass: Provides good corrosion resistance and is non-magnetic, often used in decorative applications or where electrical conductivity is a concern.
Plastic/Nylon: Lightweight and non-conductive, used in specific electronic or chemical applications where metal is unsuitable.
Choosing the Right Size and Thread
Diameter: Measured in fractions of an inch (e.g., #8, 1/4", 5/16") or millimeters. Ensure it matches the hole size and load requirements.
Length: Measured from the bearing surface to the tip. Select a length that allows for adequate thread engagement without bottoming out or protruding excessively.
Thread Pitch: Refers to the number of threads per inch (TPI) for standard UNC (coarse) or UNF (fine) threads. Coarse threads are stronger and easier to start, while fine threads offer finer adjustment and better resistance to vibration.
Frequently Asked Questions
What is the difference between a socket head cap screw and a socket set screw?
A socket head cap screw has a distinct cylindrical head with a hexagonal socket, used for joining components. A socket set screw, on the other hand, is headless and designed to secure one part against another, often to prevent movement.
Why are socket head screws often made of stainless steel?
Stainless steel offers superior resistance to rust and corrosion compared to many other metals. This makes socket head screws made from stainless steel ideal for use in humid environments, outdoors, or any application where exposure to moisture is likely.
How do I determine the correct length for a socket head screw?
Screw length is typically measured from the underside of the head to the tip of the screw. You need to ensure the screw is long enough to engage enough threads in the mating part for a secure hold, but not so long that it bottoms out or protrudes unnecessarily.
What does 'alloy steel' mean for a socket head screw?
Alloy steel indicates that the screw is made from a blend of steel and other elements, like chromium or molybdenum, to enhance its properties. These screws are often heat-treated to achieve high tensile strength and durability, making them suitable for demanding applications.
Are there specific tools needed for socket head screws?
Yes, socket head screws require a specific tool known as an Allen wrench or hex key. These wrenches fit into the hexagonal socket on the screw head, allowing you to apply torque to tighten or loosen them.
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