4-40 Bolts | McMaster-Carr

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System of Measurement

Length

Thread Size

Material

Aluminum Oxide Ceramic

Stainless Steel

Fastener Head Type

Drive Style

Drilled Spanner

Tamper-Resistant Hex

Tamper-Resistant Torx

Threading

Partially Threaded

Finish

Black Zinc Plated

Corrosion-Resistant Coated

Tin Zinc Plated

Titanium Carbon Nitride (TiCN) Coated

Zinc Yellow-Chromate Plated

Head Height

Head Diameter

Socket Head Profile

Head Width

Thread Spacing

Specifications Met

Federal Specification

Screw Size

Thread Type

Tensile Strength

Less than 10,000 psi

10,000 psi to 19,999 psi

20,000 psi to 29,999 psi

30,000 psi to 99,999 psi

100,000 psi or greater

Drive Size

Fastener Strength Grade/Class

Rounded Head Style

Thread Fit

Metric Class 6g

Metric Class 6H

Unified Standard Class 1A

Unified Standard Class 1B

Unified Standard Class 2A

Unified Standard Class 2B

Unified Standard Class 3A

Unified Standard Class 3B

Thread Direction

DFARS Specialty Metals

Export Control Classification Number (ECCN)

RoHS

Compliant with Exemptions

REACH

How can we improve?

2,715 Products

Fastening and Joining

Hex Head Screws

Hex Head Screws

Used with nuts to create a stronger joint than flat and rounded screws

Socket Head Screws

Socket Head Screws

With a deeper drive than flat and rounded head screws, these withstand more torque for a tighter hold

Rounded Head Screws

Rounded Head Screws

Sit just above the surface for a low-profile finish and hold tighter than flat head screws

Flat Head Screws

Flat Head Screws

Fit in countersunk holes for a flush finish that won't snag on surrounding parts

Shoulder Screws

Shoulder Screws

Rotate parts around the cylinder under the head to guide and align them during installation

Tighten and loosen by hand without the need for tools

Set Screws

Exert pressure at the tip to hold parts in place, unlike screws that hold material together with threads

Tapping Screws

Fasten a range of materials together without needing to tap the hole first

Captive Panel Screws

Captive Panel Screws

Secure panels and enclosures while still having access to them

Jack Screws

Secure computer cables and panels

Oval Head Screws

Oval Head Screws

The domed top sits slightly above the surface of countersunk holes for a decorative look

Studs

Press, weld, or screw in place to add a threaded fastening point

Standoff Caps

Create a finished look on standoffs and protect them from dirt and debris

Standoffs

Threaded to separate or connect parts as well as position components in assemblies

Threaded Rods

Anchor, connect, or hang components in a wide variety of applications

Thread Adapters

Thread Adapters

Join threads of a different type, size, and gender

Rivet Nuts

Add threads to thin panels with access from only one side; also known as blind inserts

Weld Nuts

Weld to metal surfaces to add permanent threads

Stud Welders

Join studs and pins to metal, leaving no marks on the back of the material

Power Transmission

Lead Screws and Nuts

Lead Screws and Nuts

Components travel along a screw with broad, square threads to clamp and lift heavy loads

Fabricating and Machining

Fixture Clamps

Secure your workpiece to a fixture table so it won't move during machining

The quick brown fox jumped over the lazy dog. Pedestal (35" Ht. x 4" Wd. x 4" Dp.)