4-40 screws are a common choice for electronics, D-sub connectors, and small hardware projects due to their compact size and reliable threading. This guide highlights top 4-40 screw kits and single screws from reputable brands, summarizing key features and uses. Whether you need a single screw for a precise fit or a full assortment for ongoing projects, the selections below offer durable stainless steel construction, varied head styles, and complete thread options to suit a range of applications.
| Brand | Product Type | Sizes | Notes |
|---|---|---|---|
| Jameco Valuepro | Jack Screw | 4-40 | For D-Sub connectors |
| MroMax | Screw Assortment Kit | #4-40, multiple lengths | 304 stainless steel |
| BNUOK | Flat Head Machine Screws | #4-40 | With hex socket, 304 stainless |
| HELIFOUNER | Screw Assortment Kit | #4-40 | 10 sizes, 304 stainless |
| uxcell | Pan Head Screws | #4-40 | 1/4″ length, 304 stainless |
Jameco Valuepro 14-556-L11.8 Jack Screw
Brand: Jameco Valuepro. Size: 4-40. Chrome finish offers corrosion resistance and a clean appearance. Recommended for D-sub connectors where small, precise fasteners are required. The zinc/chrome finish enhances durability in light to moderate environments. This jack screw is designed for secure mating in electronic assemblies and provides reliable torque transfer in constrained spaces. Suitable for hobbyist and professional electronics work.
310Pcs #4-40 Phillips Pan Head Machine Screws Assortment Kit
Brand: MroMax. Size: #4-40. An assortment kit with 310 pieces in multiple lengths (#4-40×3/16″ to #4-40×1″). Made from 304 stainless steel for rust and corrosion resistance with deep, smooth threads and burr-free cuts. Phillips pan head design provides easy drive and reliable seating. This kit is suited for general repairs, electronics assemblies, and DIY projects requiring a broad selection of #4-40 screws and matching nuts.
BNUOK #4-40 Screws, 100Pcs Flat Head Socket Caps
Brand: BNUOK. Material: 304 stainless steel with black zinc finish for corrosion resistance and high durability. Flat head countersunk design permits flush mounting, suitable for woodworking or metal surfaces. Includes screws with hex socket heads for stable torque transmission and clean installation. The set provides reliable threading and a professional finish for electronics enclosures and small assemblies.
HELIFOUNER 240 Pieces #4-40 Assortment Kit
Brand: HELIFOUNER. Sizes include 3/16″ to 1″ lengths with 10 size variants, all in 304 stainless steel. Coarse thread and fully machine threaded for versatile mounting. Comes in a durable storage box for easy size identification and access. Suitable for electronics, appliances, and general hardware projects requiring a range of #4-40 screws.
uxcell #4-40 x 1/4 Pan Head Screws
Brand: uxcell. Material: 304 stainless steel with bright finish. Includes 25 pieces of #4-40 x 1/4″ pan head machine screws. Phillips drive, full thread, and wide bearing design for stable torque transfer. Suitable for electronics enclosures, appliances, and instrument assemblies where a flush, clean appearance matters.
iexcell 100 Pcs #4-40 Hex Socket Button Head Screws
Brand: iexcell. Includes 100 pieces of #4-40 x 1/4″ hex socket button head screws in stainless steel 304. Features a hex drive (1/16″ size) for secure torque transmission and easy driving with the included hex key. Suitable for projects requiring a smaller, robust, and aesthetically pleasing fastener with a clean button head profile.
Buying Guide
Key considerations when selecting 4-40 screws:
- Material and finish: Stainless steel (304) offers corrosion resistance for electronics and outdoor use; black zinc adds rust protection and a distinctive look.
- Head style: Pan head, flat head, and button head serve different flushness and torque transfer needs. Choose flush fittings for surfaces that must remain smooth.
- Thread length and total length: Ensure the screw reaches the required depth without protrusion. Consider fully threaded versus partial threaded for load direction and grip.
- Drive type: Phillips, hex socket, or slotted drives affect ease of installation and torque control in tight spaces. Include a matching driver if purchasing in a kit.
- Quantity and assortment: Kits with multiple lengths prevent interruptions during projects; individual screws are ideal for precise, repeat tasks.
- Packing and organization: A transparent case or labeled tray helps quickly locate sizes during assembly and maintenance.
- Compatibility: Verify the screw’s diameter, pitch (40 TPI for #4-40), and thread style match the corresponding nuts and components you plan to use.
- Application environment: For high humidity or salt exposure, prioritize stainless steel and appropriate coatings to extend service life.