Brass Flat Head Socket Cap Screws

Brass flat head socket cap screws are designed for countersunk assemblies where the installed head should sit flush with, or close to, the surrounding surface. Their flat-head geometry reduces surface projection, while the internal hex socket allows installation with a hex key in areas where external wrench clearance may be limited.

These fasteners are commonly used in electrical equipment, decorative hardware, instrumentation, controls, access panels, light-duty machinery, fixtures, display equipment, enclosures, and maintenance applications where brass material and a countersunk profile are specified. A properly prepared countersink helps the head seat cleanly and can reduce snag points, improve clearance around adjacent parts, and create a smoother finished surface.

Brass is often selected for its appearance, general corrosion resistance, electrical conductivity, and nonferrous composition. It can be useful in assemblies where alloy steel or stainless steel is not the specified material. Final product selection should still reflect the actual mechanical, environmental, electrical, and dimensional requirements of the application.

Cold Headers supplies brass flat head socket cap screws in a range of inch thread sizes and lengths, including uncommon and difficult-to-source configurations. Individual product pages should be reviewed for exact thread size, overall length, nominal body diameter, head diameter, hex socket size, key engagement where verified, and other available dimensional information.

Why Use a Brass Flat Head Socket Cap Screw?

  • Flush installation: The countersunk head is intended to seat within a properly prepared countersink.
  • Reduced surface projection: Helps improve clearance around covers, panels, fixtures, and adjacent components.
  • Internal hex drive: Supports installation with a hex key where external wrench access is limited.
  • Brass construction: Offers a nonferrous material option with a distinctive appearance and useful electrical and corrosion-related characteristics.
  • Exact-size selection: Product pages allow engineers and purchasers to compare thread, length, head, body, and socket dimensions.

Selecting the Correct Brass Flat Head Socket Cap Screw

Begin by confirming the required thread size and overall screw length. Then review the head diameter and countersink requirements to make sure the fastener seats properly without excessive projection or over-travel. The hex socket size should match the intended installation tool, while the available body and key-engagement dimensions can help confirm fit and drive access. Do not assume a brass fastener is interchangeable with a steel or stainless product solely because the nominal size is the same.

Cold Headers Inc. has supplied specialty industrial socket fasteners since 1962. Our catalog is structured to help engineers, distributors, maintenance teams, and purchasing professionals locate exact sizes, uncommon lengths, and hard-to-find socket products without unsupported inventory claims.

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.

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4-40 x 1/4 Brass Flat Head Socket Cap Screw
List Price (per 100 pieces) $29.00
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4-40 x 3/8 Brass Flat Head Socket Cap Screw
List Price (per 100 pieces) $31.00
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4-40 x 1/2 Brass Flat Head Socket Cap Screw
List Price (per 100 pieces) $33.00
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4-40 x 5/8 Brass Flat Head Socket Cap Screw
List Price (per 100 pieces) $34.00
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4-40 x 3/4 Brass Flat Head Socket Cap Screw
List Price (per 100 pieces) $35.00
Description N/A

4-40 x 1/4 Brass Flat Head Socket Cap Screw is a brass flat head socket cap screw for assemblies that use a prepared countersink to reduce surface projection.

The 82-degree flat head is intended for a properly prepared countersunk hole; final seating depends on the mating countersink and the surrounding assembly geometry. Typical uses include electrical enclosures, control panels, and communication equipment, where reduced projection, socket-drive access, and a clean exposed surface can matter.

Brass may be specified for nonferrous construction, electrical conductivity, distinctive appearance, and general resistance to ordinary atmospheric corrosion. For this 4-40 thread and 1/4 in. length, review the body diameter, head diameter, head height, hex socket size, and key engagement before approving the fastener for a countersunk assembly. Cold Headers has supplied specialty industrial socket fasteners since 1962 and supports buyers looking for exact brass socket screw sizes.

Technical Highlights

  • Material: Brass
  • Thread Size: 4-40
  • Length: 1/4 in.
  • Nominal Body Diameter: 0.112 in.
  • Head Diameter: 0.218-0.255 in.
  • Head Height: 0.083 in.
  • Hex Socket Size: 1/16 in.
  • Drive Type: Internal Hex
  • Minimum Key Engagement: 0.055 in.

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.

 		N/A

4-40 x 3/8 Brass Flat Head Socket Cap Screw gives engineers a brass internal-hex fastener for countersunk holes where a smooth exposed face is part of the design.

Brass may be specified for nonferrous construction, electrical conductivity, distinctive appearance, and general resistance to ordinary atmospheric corrosion. It may be used in instrumentation, laboratory fixtures, and display hardware when the design already calls for a brass countersunk socket fastener.

The 82-degree flat head is intended for a properly prepared countersunk hole; final seating depends on the mating countersink and the surrounding assembly geometry. For this 4-40 thread and 3/8 in. length, review the body diameter, head diameter, head height, hex socket size, and key engagement before approving the fastener for a countersunk assembly. Cold Headers has supplied specialty industrial socket fasteners since 1962 and supports buyers looking for exact brass socket screw sizes.

Technical Highlights

  • Material: Brass
  • Thread Size: 4-40
  • Length: 3/8 in.
  • Nominal Body Diameter: 0.112 in.
  • Head Diameter: 0.218-0.255 in.
  • Head Height: 0.083 in.
  • Hex Socket Size: 1/16 in.
  • Drive Type: Internal Hex
  • Minimum Key Engagement: 0.055 in.

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.

 		N/A

4-40 x 1/2 Brass Flat Head Socket Cap Screw is commonly specified when a brass socket-drive screw needs to seat into a flat-head countersink rather than stand proud of the surface.

When the countersink is prepared correctly, the flat head can sit flush with or close to the surrounding surface to reduce snag points and improve clearance. This makes the product useful for access covers, equipment panels, and interior equipment, especially where raised hardware could interfere with adjacent components.

Cold Headers has supplied specialty industrial socket fasteners since 1962 and supports buyers looking for exact brass socket screw sizes. Brass may be specified for nonferrous construction, electrical conductivity, distinctive appearance, and general resistance to ordinary atmospheric corrosion. For this 4-40 thread and 1/2 in. length, review the body diameter, head diameter, head height, hex socket size, and key engagement before approving the fastener for a countersunk assembly.

Technical Highlights

  • Material: Brass
  • Thread Size: 4-40
  • Length: 1/2 in.
  • Nominal Body Diameter: 0.112 in.
  • Head Diameter: 0.218-0.255 in.
  • Head Height: 0.083 in.
  • Hex Socket Size: 1/16 in.
  • Drive Type: Internal Hex
  • Minimum Key Engagement: 0.055 in.

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.

 		N/A

4-40 x 5/8 Brass Flat Head Socket Cap Screw supports panel and fixture designs that require a brass countersunk screw with top-side hex socket access.

Applications can include decorative hardware, architectural components, and bracket assemblies. The material is often selected where the assembly requires brass hardware for electrical equipment, controls, instrumentation, or appearance-sensitive components.

When the countersink is prepared correctly, the flat head can sit flush with or close to the surrounding surface to reduce snag points and improve clearance. Cold Headers has supplied specialty industrial socket fasteners since 1962 and supports buyers looking for exact brass socket screw sizes. For this 4-40 thread and 5/8 in. length, review the body diameter, head diameter, head height, hex socket size, and key engagement before approving the fastener for a countersunk assembly.

Technical Highlights

  • Material: Brass
  • Thread Size: 4-40
  • Length: 5/8 in.
  • Nominal Body Diameter: 0.112 in.
  • Head Diameter: 0.218-0.255 in.
  • Head Height: 0.083 in.
  • Hex Socket Size: 1/16 in.
  • Drive Type: Internal Hex
  • Minimum Key Engagement: 0.055 in.

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.

 		N/A

4-40 x 3/4 Brass Flat Head Socket Cap Screw is intended for applications where brass material and flat-head socket geometry are both called out by the drawing or bill of materials.

This head style differs from button head, low head, and cylindrical socket head screws because the head is designed to nest into a matching countersunk seat. Typical uses include fixtures, housings, and low-load mechanical assemblies, where reduced projection, socket-drive access, and a clean exposed surface can matter.

The material is often selected where the assembly requires brass hardware for electrical equipment, controls, instrumentation, or appearance-sensitive components. For this 4-40 thread and 3/4 in. length, review the body diameter, head diameter, head height, hex socket size, and key engagement before approving the fastener for a countersunk assembly. Cold Headers helps industrial distributors, sourcing teams, and maintenance operations identify uncommon lengths and specialty socket products.

Technical Highlights

  • Material: Brass
  • Thread Size: 4-40
  • Length: 3/4 in.
  • Nominal Body Diameter: 0.112 in.
  • Head Diameter: 0.218-0.255 in.
  • Head Height: 0.083 in.
  • Hex Socket Size: 1/16 in.
  • Drive Type: Internal Hex
  • Minimum Key Engagement: 0.055 in.

Call 773-775-7900 or email Sales@coldheaders.com for pricing, availability, or a quote.
Brands N/A Cold Headers, Inc.
Diameter N/A 4-40
Length N/A 1/4 in N/A 3/8 in N/A 1/2 in N/A 5/8 in N/A 3/4 in
Material N/A Brass
Quantity N/A 100
Package Type N/A Box