4-40 Fasteners | McMaster-Carr

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System of Measurement

Thread Size

Length

Material

Stainless Steel

Fastener Head Type

Drive Style

Drilled Spanner

External Square

Tamper-Resistant Hex

Tamper-Resistant Torx

Threading

Partially Threaded

Finish

Black Zinc Plated

Cadmium Yellow-Chromate Plated

Corrosion-Resistant Coated

Dry Film Lubricated

Phosphate Coated

Tin Zinc Plated

Titanium Carbon Nitride (TiCN) Coated

Head Diameter

Specifications Met

Federal Specification

Socket Head Profile

Head Height

Rounded Head Style

Thread Type

Drive Size

Countersink Angle

Flat Head Profile

Thread Direction

Screw Size

Thread Spacing

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

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

DFARS Specialty Metals

RoHS

Compliant with Exemptions

Export Control Classification Number (ECCN)

REACH

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3,577 Products

Fastening and Joining

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

Hex Head Screws

Hex Head Screws

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

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

Shoulder Screws

Shoulder Screws

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

Captive Panel Screws

Captive Panel Screws

Secure panels and enclosures while still having access to them

Jack Screws

Secure computer cables and panels

Studs

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

Tapping Screws

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

Hex Nuts

Handle most general fastening needs

Locknuts

Hold fasteners in place to prevent loosening from vibration

Easy to tighten and loosen by hand for making frequent adjustments

Flange Nuts

The flange distributes pressure, so you don't need a washer

Socket Nuts

Install in recessed holes and tight spots where a wrench won’t fit; also known as Allen nuts

Coupling Nuts

Connect and extend threaded rods

Cap Nuts

Cover and protect threads while adding a finished look; also known as acorn nuts

Square Nuts

Flat sides won’t spin in channels and square holes

Press-Fit Nuts

Push into drilled or punched holes to add threads to thin panels

Threaded Inserts

Threaded Inserts

Create new threads or repair stripped threads

Push Nuts

Press onto threads for a light duty hold that’s faster to install than typical nuts

Rivet-Mount Nuts

Rivet-Mount Nuts

Add threads in hard-to-reach areas and materials that are too thin to be tapped

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

Adhesive-Mount Nuts

Adhesive-Mount Nuts

Attach threads to material that’s too thin for a threaded insert

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

Press-Fit Nut Installation Tools

Press-Fit Nut Installation Tools

Everything you need to install press-fit nuts by hand

Rivet Nut Tools

Rivet Nut Tools

Install rivet nuts

Fabricating and Machining

Fixturing Clamps

Fixturing 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.)