Cap Plugs | McMaster-Carr

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Adjustable-Angle Elbow

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U.S.–Mexico–Canada Agreement (USMCA) Qualifying

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Export Control Classification Number (ECCN)

2A992

2B999

EAR99

DFARS Specialty Metals

11,180 Products

Building and Machinery Hardware

Protective Plugs

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

1,009 products

Protective Caps

Protect just about anything, including pipe, flanges, screws, and posts

1,070 products

Fluid Handling

Tube End Caps

Cover the ends of tube to keep out dirt and debris

394 products

Tube End Plugs

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

260 products

Tube Fittings

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

363 products

Tubing Flow Stops

Temporarily block water flow to make soldering repairs without waiting for your line to drain

9 products

Pipe and Fittings

Generally thicker and more rigid than tubing for distributing liquids and gases

2,208 products

Hose and Hose Fittings

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

279 products

Expansion Plugs

Seal pipe and tubing lines when checking for leaks

346 products

Bore Sealing Plugs

Permanently seal unthreaded holes in pneumatic and hydraulic components

95 products

Thermocouple Connector Covers

Shield thermocouple connectors from dust and debris

1 product

Sights

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

246 products

Breather Vents

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

14 products

Pressure Test Fittings

Create a temporary connection point for gauges and other testing equipment

31 products

Pressure-Relief Valves

Protect equipment by opening at a set pressure and closing when the pressure drops; for repeated use

17 products

Heat Exchanger Plugs

Plug leaky internal tubes in heat exchangers

17 products

Electrical Power, Networking, and Controlling

Power Connectors

Plugs, sockets, receptacles, and other connectors for powering equipment

1,315 products

Metric Circular Connectors

Plugs, sockets, receptacles, and adapters for equipment with metric connections

112 products

Latching Connectors

Protect connections in wet or harsh environments while keeping them accessible

173 products

RJ45 Plugs

Pair with sockets or receptacles to make Ethernet connections

25 products

Breakaway Plugs

Mate with sockets or receptacles to make connections that separate before anything breaks

1 product

USB Plugs

Pair with sockets and receptacles to make USB connections

4 products

DMX Connectors

Replace damaged plugs and sockets on lighting cables

2 products

Ecomate Connectors

Connect machine tools, robots, and other vibrating equipment

14 products

Mil. Spec. Connectors

Meet strict military standards or are compatible with Mil. Spec. connectors

114 products

Molex Connectors

Plugs, sockets, and housings for making Molex connections

123 products

Micro 360 Connectors

Plugs and sockets to make control and data connections in tight spaces

12 products

Mini Connector Thread Adapters

Join two connectors that both have internal threads

6 products

AMP Connectors

Build-your-own and ready-to-use AMP connectors

80 products

Coaxial Plugs

Pair with sockets or receptacles to make coaxial connections

28 products

Ballast Connectors

Avoid exposure to live wires when replacing fluorescent ballasts

2 products

Sure Seal Connectors

A PVC housing keeps out liquids and dust and resists chemicals

6 products

Mini Connectors

Plugs, sockets, and receptacles send power and control signals to equipment and automated systems

29 products

D-Sub Connectors

Plugs, sockets, receptacles, and adapters for connecting computers, monitors, and printers

138 products

Han Connectors

Plugs and sockets to make Han connections

6 products

Solenoid Valve Connectors

Sockets and receptacles to connect solenoid components, such as valves and motors

20 products

Audio Plugs

Pair with sockets or receptacles to make audio connections

6 products

Amphenol Plugs

Mate with a housing to attach wires to a circuit board

13 products

Electrical Connector Caps

Protect data connectors when not in use

78 products

USB Cords

Transfer data between computers, printers, and mobile devices

252 products

Metric Circular Cords

Send power and signal to equipment with metric connections

307 products

Power Cords

Connect equipment and devices to a power source

9 products

Data Port Plugs

Keep dust, debris, and moisture out of unused computer ports

3 products

USB Chargers

Power up mobile devices and other electronics

19 products

Welding Cable Connectors

Plugs and sockets to deliver power to welding cable

10 products

Data Port Locks

Block USB or Ethernet ports from unauthorized use

9 products

Electrical Enclosure Plugs

Block or seal holes in outlet boxes and enclosures to keep out debris, dust, and moisture

77 products

Heat-Shrink Tubing End Caps

Seal moisture out of crimped electrical connections

22 products

Cold-Shrink Tubing End Caps

Seal crimped electrical connections without heat or tools to protect against moisture

4 products

DIN Rail Caps

Guard the edges of DIN rail from damage and create a finished look

2 products

Electrical Enclosure Drains

Release moisture to keep components dry

4 products

Electrical Enclosure Drain Vents

Prevent moisture from getting trapped inside enclosures while letting air flow through

5 products

Circuit Breaker Box Filler Plates

Conceal live electrical components in circuit breaker boxes to prevent injury and damage

2 products

Capacitor Boots

Shield capacitors and wire connections to extend their service life and reduce accidental shocks

3 products

Lubricating

Grease Fittings

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

360 products

Grease Fitting Caps

Protect grease fittings from dirt, debris, and moisture

14 products

Grease Fitting Adapters

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

41 products

Grease Fitting Repair Tools

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

2 products

Grease Fitting Cleaning Tools

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

2 products

Grease Fitting Junction Blocks

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

9 products

Grease Fitting Manifolds

Lubricate multiple points with the same amount and type of grease using one grease fitting

3 products

Grease Fitting Installation Tools

Tap to insert grease fittings in unthreaded holes

2 products

Oil Fittings

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

36 products

Containers, Storage, and Furniture

Syringe Caps

Cover syringe tips when not in use to protect them and prevent leaks

13 products

Drum Plugs

Seal drum lid openings

27 products

Drum Plug Caps

Access inside drums to fill them

4 products

Drum Locks

Secure drum lids and openings to prevent tampering

3 products

Dust Covers

Stretch over drums, pails, and other objects to keep out dust and debris

16 products

Stacking Caps and Targets

Turn the ends of posts into stackable shelving and rack systems

6 products

Measuring and Inspecting

Hose Coupling Size-Identification Kits

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

1 product

Fabricating and Machining

Fixture Plate Plugs

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

8 products

Tooling Ball Covers

Protect tooling balls when not in use

3 products

Lighting

Light Switch/Receptacles

Combine a switch and receptacle into a single outlet box for a small footprint

1 product

Facility and Grounds Maintenance

Sink Drain Stoppers

Plug drains to fill up sinks and tubs

5 products

Sink Drains

Empty liquids from sinks into sewer lines

19 products

Faucet Hole Covers

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

2 products

Floor Drain Trap Seals

Stop sewer gases from escaping through rarely used floor drains if the P-trap dries out

4 products

Drain Cleanouts

Create an access point to inspect and clean floor drain pipelines

3 products

Rebar Caps

Brightly colored to alert workers to exposed rebar and pipe

4 products

Heating, Ventilation, and Air Conditioning

Duct Vent Caps

Reduce downdrafts and prevent obstructions from entering vents

36 products

Chimney Pipe and Fittings

Exhaust hot air and fumes from boilers, furnaces, and stoves

20 products

Air Conditioner Service Valve Caps

Seal off AC service valves to prevent refrigerant from leaking out

2 products

Temperature-Controlled Outlet Adapters

Automatically turn heating and cooling devices on and off as temperatures rise and fall

3 products

Fastening and Joining

Standoff Caps

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

66 products

Quick-Release Pin Receptacles

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

36 products

Quick-Release Pin Retaining Caps

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

23 products

Safety Equipment

Fire Hydrant Caps

Pair with a hook-style spanner wrench to quickly cover and uncover fire hydrants

6 products

Fire Hydrant Plugs

Pair with a hook-style spanner wrench to quickly seal fire hydrants and washdown equipment

3 products

Bearing Guards

Shield bearings from dirt, and protect fingers and tools from moving parts

14 products

Floor Drain Plugs

Prevent oil and other spills from going down your floor drain

3 products

Spill-Control Drain Covers

Block grates and manholes so liquid can't get in and odors can't get out

6 products

Material Handling

Conveyor Guide Mounting Rod Caps

Cover the ends of conveyor guide mounting rods for a finished look

7 products

Power Transmission

Die Spring Screw Caps

Brace springs and control tension in die sets while simplifying maintenance

10 products

Sealing

Drum Plug Gaskets

Form a tighter seal in drum openings than with a drum plug alone

7 products

Communication

Tamper-Evident Seals

Secure hasps, latches, and other connections to visibly indicate tampering

2 products