Metal Caps | McMaster-Carr

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Alcohol-Based Solvents

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DFARS Specialty Metals

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Chromate Conversion Coated

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8,084 Products

Fluid Handling

Pipe and Fittings

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

2,286 products

Tube End Caps

Cover the ends of tube to keep out dirt and debris

263 products

Tube End Plugs

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

89 products

Tube Fittings

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

87 products

Hose End Caps

Cover the ends of hose to keep out dirt and debris

124 products

Hose Fittings

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

1,053 products

Hose End Plugs

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

9 products

Hose

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

28 products

Expansion Plugs

Seal pipe and tubing lines when checking for leaks

238 products

Bore Sealing Plugs

Permanently seal unthreaded holes in pneumatic and hydraulic components

69 products

Air Vent Valves

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

1 product

Breather Vents

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

88 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

136 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

84 products

Protective Plugs

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

198 products

Knobs

Position, tighten, and secure fixtures and equipment

229 products

Slip-On Framing and Fittings

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

9 products

Strut Channel Framing and Fittings

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

47 products

T-Slotted Framing and Fittings

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

2 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

36 products

Protective Feet

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

24 products

Vibration-Damping Mounts

Attach to machinery to reduce vibration and noise and extend service life

7 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

Door Drip Guards

Divert rain and snow away from door openings

10 products

Fastening and Joining

Cap Nuts

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

344 products

Retaining Rings

Hold components on a shaft

305 products

Standoff Caps

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

65 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

Socket Retaining Rings

Secure sockets and adapters to impact tools

3 products

Electrical

Electrical Connector Caps

Protect data connectors when not in use

31 products

Electrical Plugs

Pair with sockets or receptacles to transmit power or data

129 products

Electrical Sockets

Pair with plugs or receptacles to transmit power or data

91 products

Wire Splices, Connectors, and Taps

Join wire and protect the connection

126 products

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

45 products

Electrical Enclosure Vents

Attach to sealed enclosures so air can flow to equalize temperature and pressure

5 products

Electrical Enclosure Drain Vents

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

4 products

Electrical Enclosure Drains

Release moisture to keep components dry

2 products

Outlet Boxes

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

5 products

Outlet Box Covers

Enclose wiring for outlets and switches or block off unused components

68 products

Weatherheads

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

10 products

Containers, Storage, and Furniture

Fuel Caps

Seal fuel tanks on trailers, compressors, and other equipment

2 products

Drum Plugs

Seal drum lid openings

9 products

Drum Lids

Replace the lid on your drum

16 products

Drum Covers

Protect drum lids from damage and rust

2 products

Drum Locking Rings

Clamp lids onto drums for a tight seal

7 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

Hard Hat Racks

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

4 products

Stacking Caps and Targets

Turn the ends of posts into stackable shelving and rack systems

6 products

Heating, Ventilation, and Air Conditioning

Duct and 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

5 products

Lubricating

Grease Fittings

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

332 products

Grease Fitting Adapters

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

29 products

Grease Fitting Manifolds

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

3 products

Grease Fitting Junction Blocks

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

9 products

Grease Fitting Repair Tools

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

2 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

Fabricating and Machining

Fixture Plate Plugs

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

5 products

Clamp Holding Screws

Replace worn holding screws in clamps or customize with different sizes or styles

52 products

Vise Jaw Liners

Place over vise jaws to protect workpieces from marring

38 products

Facility and Grounds Maintenance

Chain Link Fencing

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

5 products

Fence Posts

Secure and hold up fencing

7 products

Rebar Caps

Brightly colored to alert workers to exposed rebar and pipe

2 products

Faucet Hole Covers

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

1 product

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

25 products

Power Transmission

Die Spring Screw Caps

Brace springs and control tension in die sets while simplifying maintenance

10 products

Safety Equipment

Fire Hydrant Caps

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

1 product

Toe and Foot Guards

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

14 products

Hard Hats

Protect your head from falling objects

1 product

Bearing Guards

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

6 products

Floor Drain Plugs

Prevent oil and other spills from going down your floor drain

3 products

Sealing

Drum Gaskets

Seal lids onto steel and stainless steel drums

6 products