Metal Caps | McMaster-Carr

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2A992

2B999

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Compliant with Exemptions

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Corrosion-Resistant Coated

Molybdenum Disulfide Coated

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8,594 Products

Fluid Handling

Pipe Caps

Cover the ends of pipe to keep out dirt and debris

458 products

Pipe Plugs

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

1,188 products

Pipe Flanges

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

980 products

Tube End Caps

Cover the ends of tube to keep out dirt and debris

335 products

Tube End Plugs

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

108 products

Tube Fittings

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

109 products

Tubing Flow Stops

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

9 products

Hose End Caps

Cover the ends of hose to keep out dirt and debris

101 products

Hose Fittings

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

1,305 products

Hose

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

62 products

Expansion Plugs

Seal pipe and tubing lines when checking for leaks

191 products

Air Vent Valves

Eliminate air pockets from fluid lines to maintain consistent flow and prevent surges

31 products

Breather Vents

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

86 products

Pressure-Relief Valves

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

17 products

Sights

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

203 products

Heat Exchanger Plugs

Plug leaky internal tubes in heat exchangers

17 products

Strainers

Install next to valves and pumps to catch debris in your line

18 products

Building and Machinery Hardware

Protective Caps

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

74 products

Protective Plugs

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

148 products

Knobs

Position, tighten, and secure fixtures and equipment

203 products

Slip-On Framing and Fittings

Insert rails into fittings and tighten screws to make guards, railings, and racks

14 products

T-Slotted Framing and Fittings

The most versatile system, attach fittings along the continuous slots to build virtually anything

24 products

Strut Channel Framing and Fittings

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

47 products

Press-Fit Framing and Fittings

Set up temporary partitions, guards, and displays using only a hammer

1 product

Leveling Mount Inserts

Slip onto equipment and furniture to add threaded-stud leveling feet

24 products

Protective Feet

Add to furniture and light equipment to protect floors from scratches and wear

18 products

Door Drip Guards

Divert rain and snow away from door openings

10 products

Grommets

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

11 products

Lockouts

Ensure that machines stay turned off to prevent accidents during maintenance work

4 products

Fastening and Joining

Cap Nuts

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

402 products

Retaining Rings

Hold components on a shaft

293 products

Standoff Caps

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

4 products

Quick-Release Pin Receptacles

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

35 products

Quick-Release Pin Retaining Caps

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

23 products

Press-Fit Nuts

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

2 products

Threaded Inserts

Create new threads or repair stripped threads

1 product

Electrical

Electrical Connector Caps

Protect data connectors when not in use

33 products

Electrical Adapters

Change electrical connectors to another type, size, or gender

1 product

Terminal Covers

Block out dirt and corrosion to protect battery terminals

2 products

Electrical Enclosure Plugs

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

55 products

Electrical Enclosure Drains

Release moisture to keep components dry

2 products

Electrical Enclosure Drain Vents

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

4 products

Outlet Box Covers

Enclose wiring for outlets and switches or block off unused components

68 products

Outlet Boxes

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

5 products

Weatherheads

Bring power into buildings and protect the entry point from rain and snow

9 products

Containers, Storage, and Furniture

Drum-Plug Caps

Access inside drums to fill them

4 products

Drum Plugs

Seal drum lid openings

9 products

Drum Lids

Replace the lid on your drum

16 products

Drum Locks

Secure drum lids and openings to prevent tampering

3 products

Drum Covers

Protect drum lids from damage and rust

2 products

Fuel Caps

Seal fuel tanks on trailers, compressors, and other equipment

2 products

Gas Tank Safety Caps

Protect valves on high-pressure gas tanks without having to remove the regulator

1 product

Gas Tank Safety Collars

Protect valves on acetylene tanks without having to remove the regulator

1 product

Stacking Caps and Targets

Turn the ends of posts into stackable shelving and rack systems

6 products

Hard Hat Racks

Keep hard hats close at hand, but out of the way

4 products

Safety Equipment

Fire Hydrant Caps

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

4 products

Fire Hydrant Plugs

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

3 products

Toe and Foot Guards

Slip over shoes or boots to shield feet and toes from impact

14 products

Heating, Ventilation, and Air Conditioning

Duct and Duct Fittings

Circulate air through HVAC systems using round, rectangular, and fabric duct

133 products

Chimney Pipe and Fittings

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

21 products

Air Conditioner Service Valves

Tap into refrigerant lines to drain and fill your system

15 products

Lubricating

Grease Fitting Adapters

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

41 products

Grease Fittings

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

368 products

Grease Fitting Manifolds

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

3 products

Grease Fitting Repair Tools

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

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 Installation Tools

Tap to insert grease fittings in unthreaded holes

2 products

Grease Fitting Cleaning Tools

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

2 products

Power Transmission

Die Spring Screw Caps

Brace springs and control tension in die sets while simplifying maintenance

10 products

Fabricating and Machining

Fixture Plate Plugs

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

1 product

Sanding Bits

Smooth out small, recessed, and hard-to-reach areas, and also remove paint and rust

173 products

Vise Jaw Liners

Place over vise jaws to protect workpieces from marring

46 products

Facility and Grounds Maintenance

Chain Link Fencing

Everything you need to build or repair a chain link fence, from posts to gates

6 products

Fence Posts

Secure and hold up fencing

7 products

Sink Drain Strainers

Catch debris to prevent clogs and plug drains to fill sinks

6 products

Sink Drains

Empty liquids from sinks into sewer lines

30 products

Faucet Hole Covers

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

1 product

Material Handling

Valve Stem Caps

Keep dust and debris out of tire valves

1 product