Steel Square-Head Plugs | McMaster-Carr

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5,464 Products

Fluid Handling

Pipe Plugs

Insert into the ends of pipe to keep out dirt and debris

Pipe Caps

Cover the ends of pipe to keep out dirt and debris

Pipe Flanges

Create an access point in a line by bolting two same-size flanges together with a gasket

Pipe Fittings

Form threaded, barbed, flanged, and other types of connections between lengths of pipe

Tube End Plugs

Insert into the ends of tube to keep out dirt and debris

Tube End Caps

Cover the ends of tube to keep out dirt and debris

Tube Fittings

Make threaded, push to connect, barbed, and other types of connections between lengths of tube

Hose Fittings

Create threaded, barbed, quick-disconnect, and other types of connections between lengths of hose

Hose End Caps

Cover the ends of hose to keep out dirt and debris

Hose

Flexible and stronger than tubing; often used to convey liquids and gases under pressure

Bore Sealing Plugs

Bore Sealing Plugs

Permanently seal unthreaded holes in pneumatic and hydraulic components

Sights

Observe and monitor the contents of pipes, tanks, and other containers

Pressure Test Fittings

Pressure Test Fittings

Create a temporary connection point for gauges and other testing equipment

Breather Vents

Maintain even pressure and vacuum as temperatures change by allowing airflow in tanks and enclosures

Building and Machinery Hardware

Protective Plugs

Protective Plugs

Insert into holes in pipe, containers, panels, and parts to keep out debris

Protective Caps

Protective Caps

Cover holes at the end of pipe, conduit, and fittings to keep out debris

Countertop Trash Chutes

Countertop Trash Chutes

Finish the hole over a waste container

Grommets

Protect wire, cable, and cords from holes with sharp or rough edges

Strut Channel Framing and Fittings

Strut Channel Framing and Fittings

Secure fittings in the U-shaped channel to route conduit and pipe or build other structures

Electrical

Electrical Enclosure Plugs

Electrical Enclosure Plugs

Cover unused holes in enclosures to keep out dust, dirt, and moisture

Electrical Enclosure Drains

Electrical Enclosure Drains

Release moisture to keep components dry

Cord Grips

Securely connect cords to enclosures while sealing out dirt and moisture

Outlet Boxes

House electrical components such as on-off switches, receptacles, and dimmer knobs

Cable Entry Panels

Cable Entry Panels

Pass multiple cords into an enclosure while sealing out moisture, dust, and other contaminants

Outlet Strips

Plug in multiple devices to power them from a single outlet

Electrical Connector Caps

Electrical Connector Caps

Protect data connectors when not in use

Wall Plates

Cover switches and outlets for a finished look or to close them off when not in use

Electrical Contact Installation Tools

Electrical Contact Installation Tools

Add or remove pin-and-sleeve contacts in connectors

Wire and Cable Crimpers

Wire and Cable Crimpers

Crimp connectors onto electrical wire or cable

Wire Stripper Crimpers

Wire Stripper Crimpers

Strip wire and crimp connectors with one tool

Wire and Cable Crimper Dies

Wire and Cable Crimper Dies

Attach to cordless crimpers to secure connectors onto cable

Battery Chargers

Battery Chargers

Charge everything from large-cell to cordless tool to household batteries

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

Hex Head Screws

Hex Head Screws

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

Flat Head Screws

Flat Head Screws

Fit in countersunk holes for a flush finish

Tapping Screws

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

Wood Screws

Fasten material to wood or pieces of wood to each other

Quick-Release Pin Receptacles

Quick-Release Pin Receptacles

Secure quick-release pins when you don’t have a through hole

Quick-Release Pin Retaining Caps

Quick-Release Pin Retaining Caps

Hold quick-release pins in holes that are oversized or out of round

Standoff Caps

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

Retaining Rings

Retaining Rings

Hold components on a shaft

Press-Fit Nuts

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

Fabric Snaps

Join soft, heavy fabrics such as leather and canvas

Rivets

Join materials together permanently, especially when too thin or fragile to fasten with screws

Lubricating

Grease Fittings

Grease Fittings

Create an inlet on equipment and machinery for injecting lubricant; also known as Zerk fittings

Grease Fitting Adapters

Grease Fitting Adapters

Mate grease fittings when the sizes and thread types don't match

Grease Fitting Cleaning Tools

Grease Fitting Cleaning Tools

Flush out old grease, dirt, and debris from clogged fittings

Grease Fitting Junction Blocks

Grease Fitting Junction Blocks

Send different types and amounts of grease from multiple grease fittings to lubricate several points

Grease Fitting Repair Tools

Grease Fitting Repair Tools

Remove and repair broken or clogged grease fittings and re-tap threaded holes

Grease Fitting Installation Tools

Grease Fitting Installation Tools

Tap to insert grease fittings in unthreaded holes

Oil Fittings

Install in engine blocks and other machinery to pour in oil while keeping dust out

Fabricating and Machining

Fixture Plate Plugs

Fixture Plate Plugs

Keep chips and shavings from clogging or damaging unused holes on fixture plates in milling machines

Measuring and Inspecting

Hose Coupling Size-Identification Kits

Hose Coupling Size-Identification Kits

Match your hose coupling to one of the plugs to determine its size without measuring

Containers, Storage, and Furniture

Drum Plugs

Seal drum lid openings

Stacking Caps and Targets

Stacking Caps and Targets

Turn the ends of posts into stackable shelving and rack systems

Facility and Grounds Maintenance

Sink Drain Strainers

Sink Drain Strainers

Catch debris to prevent clogs and plug drains to fill sinks

Sink Drains

Empty liquids from sinks into sewer lines

Faucet Hole Covers

Faucet Hole Covers

Close off unused faucet holes intended for soap dispensers and side sprayers

Sealing

Tube Fitting Gaskets

Tube Fitting Gaskets

Prevent leaks when connecting sanitary tube fittings

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