- Manufacturer: Losi
- Part Number: Z-LOSA6221
- EAN: 660132005641
- Thread Size: 4-40
- Length: 5/8 inch
- Head Type: Cap Head
- Driver Type: Hex Socket
- Colour: Black
- Quantity: 6 pieces
- Material: Steel
- Finish: Black coating for corrosion resistance
Overview
The Losi 4-40 x 5/8 inch Cap Head Screws (6) Z-LOSA6221 are precision-engineered fasteners designed for RC car enthusiasts and hobbyists across the UK who demand reliable, high-quality components. Whether you're maintaining your Losi RC vehicle, performing routine upgrades, or undertaking comprehensive repairs, these socket head cap screws deliver the durability and precision fit that serious RC builders expect. As an essential spare part for Losi RC models, these screws are an absolute must-have for your RC hobby toolkit.
These black hex socket head cap screws are manufactured to exacting standards by Losi, a recognised leader in the RC car industry. If you own a Losi RC buggy, RC truggy, or any other Losi-based RC vehicle, having a supply of quality replacement fasteners ensures your model stays in peak condition. The 4-40 thread specification paired with the 5/8 inch length makes these screws suitable for a wide range of assembly and repair applications on Losi RC platforms. Whether you're a seasoned RC racer, a weekend basher, or someone new to the RC car hobby in the UK, maintaining spare fasteners is fundamental to keeping your model in working order.
Cap head socket screws are preferred by RC enthusiasts because they offer superior holding power compared to standard fasteners, and the hex socket design allows for precise torque application without risk of stripping the fastener head. This pack contains six screws, providing you with multiple replacements for lost, damaged, or worn fasteners across your RC vehicle collection.
Key Features
- 4-40 Thread Specification — The 4-40 metric designation is a standard fastener size widely used throughout Losi RC vehicles and components, ensuring universal compatibility across multiple models and assembly points.
- 5/8 Inch Length — This length specification is carefully engineered to work with Losi's suspension systems, chassis assemblies, and body mounting points, providing the correct engagement depth without protruding excessively.
- Cap Head Socket Design — The cap head configuration offers a larger bearing surface than traditional fasteners, distributing load more effectively and reducing the risk of stripping plastic or aluminium components commonly found on RC cars.
- Hex Socket Driver — The hex socket accepts standard hex Allen keys or socket drivers, allowing you to apply precise torque without risk of cam-out or fastener damage, which is essential for maintaining critical assemblies on your RC model.
- Black Finish — The black coating provides corrosion resistance and a professional appearance, protecting the fasteners from moisture and dirt common in outdoor RC racing and bashing environments.
- Pack of Six — Six screws per pack means you have multiple replacements on hand, reducing downtime during maintenance and repair sessions and ensuring you can complete comprehensive rebuild projects without waiting for additional parts.
- OEM Losi Product — Manufactured by Losi themselves, these are genuine original equipment manufacturer parts, guaranteeing compatibility, material quality, and reliability that third-party alternatives simply cannot match.
Technical Performance
These Losi cap head screws are manufactured from high-grade steel that provides exceptional strength-to-weight ratio, critical for applications where fastener failure could compromise vehicle performance or safety. The 4-40 thread profile has been engineered to work seamlessly with Losi's precision-machined receiving holes and threaded inserts, ensuring a secure fit without stripping or cross-threading. The hex socket design prevents the common problem of fastener head damage that occurs with standard slot-head or Phillips-head fasteners, which lose their grip and become impossible to remove once stripped. The 5/8 inch length is precisely calibrated to engage adequately with Losi's mounting points whilst avoiding protrusion that could interfere with suspension geometry, steering linkages, or body clearances. The black finish is applied through a process that provides long-lasting corrosion resistance even when exposed to water, mud, and salt—common hazards for RC vehicles used in UK outdoor conditions. Whether you're working on competitive RC racing builds, casual RC car bashing sessions, or restoration projects on classic Losi models, these fasteners represent the quality standard you should expect.
What's in the Box
- Losi 4-40 x 5/8 inch Cap Head Screws (6 pieces)
Frequently Asked Questions
- What are cap head socket screws used for on RC cars? — Cap head socket screws are used throughout RC vehicle assemblies including suspension mounting points, servo mounting brackets, body mounts, chassis attachments, and drivetrain components. The larger head design provides better load distribution, making them ideal for plastic and aluminium components commonly found on RC buggies, RC trucks, and RC racing platforms.
- Will these Losi screws fit my RC vehicle? — These 4-40 x 5/8 inch screws are specifically engineered by Losi for their RC car range. If you own a Losi RC model, check your assembly manual or contact us to confirm the correct fastener size for your specific vehicle. Using the correct fastener specification is essential to avoid stripping holes or compromising assembly integrity.
- How many replacement screws do I need? — This pack contains six screws, which provides multiple replacements for lost or damaged fasteners. Depending on your project scope, you may wish to purchase additional packs to maintain a comprehensive spare parts inventory for frequent maintenance and repair work.
- What is the difference between cap head screws and other fastener types? — Cap head screws feature a larger cylindrical head that sits flush against components, distributing load across a wider surface area compared to standard bolts. The hex socket design is more reliable than Phillips or slot-head alternatives because it resists cam-out, making it superior for precision RC work where fastener damage could delay or complicate projects.
- Are these screws suitable for beginners? — Yes, these screws are an essential spare part for any RC enthusiast, whether you are just starting your RC hobby or have years of experience. Understanding fastener maintenance is one of the fundamental skills for RC car ownership, and stocking quality replacement parts builds confidence in performing your own maintenance and repairs.
- How do I apply the correct torque to these screws? — Use a hex socket driver or Allen key with a torque wrench set to manufacturer specifications (typically found in your vehicle's assembly manual). Apply consistent, even pressure to avoid over-tightening, which can strip plastic receiving holes, or under-tightening, which can lead to loose assemblies and poor vehicle performance.
Why Buy from RC Model Shop?
RC Model Shop is a trusted UK RC retailer and authorised dealer for all the brands we stock, including Traxxas, ARRMA, Losi, FTX, Hobbywing, Spektrum and more. Based in Walsall, we have a physical store where customers are welcome to come in, view products and purchase in store. Whether you are a seasoned competitor, a weekend basher, or just discovering the world of RC for the first time, our team of experienced RC enthusiasts is here to help you find the perfect setup and provide ongoing support. Order the Losi 4-40 x 5/8 inch Cap Head Screws (6) Z-LOSA6221 today with confidence, knowing you are buying from an authorised retailer with genuine products, expert knowledge and a commitment to customer satisfaction. Shop online or visit us in Walsall — we look forward to helping you get the most out of your RC experience.
We want to make sure your delivery goes smoothly, so here are some important details about our service:
- For orders above £120, we offer delivery to most mainland UK addresses. For orders under £120, we can still deliver to Northern Ireland and the outlying isles, as long as the item can be sent by Royal Mail, weighs less than 30kg, and fits within 61cm × 46cm × 46cm. Some highland and remote areas may carry an extra delivery charge as couriers often apply surcharges in these locations. If you live in one of these areas, feel free to contact us before ordering so we can confirm the delivery options and costs for you.
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