Round Tube Inserts | McMaster-Carr

	REACH (Registration, Evaluation, Authorization and Restriction of Chemicals) REACH (Registration, Evaluation, Authorization and Restriction of Chemicals)

REACH Compliant

	Height Height

	Head Diameter Head Diameter

	For Pipe Size For Pipe Size

1/16
1/8
1/4
3/8
1/2
3/4
1
1 1/4
1 1/2
2
2 1/2
3
3 1/2
4
5
6
8
10
12
14
16
18
20

	For Tube OD For Tube OD

	For Surface Type For Surface Type

Unthreaded

Threaded

	Flexibility Flexibility

Flexible

Rigid

	Hardness Hardness

	For Tube ID For Tube ID

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2,079 Products

Round Plugs

Snap-In Round Plugs

Flexible ridges or straps hold these plugs in place and allow them to fit a range of hole diameters.

Conductive Round Plugs

With a surface resistivity of less than 10⁵ ohms, these plugs not only dissipate electrical charges, but can be used as an electrical shield.

Sealing Plugs

With a compressible flanged top, these plugs are designed to seal the ends of copper tubing often used in water supply lines, refrigerant lines, and HVAC compressors. All are sized to fit standard copper tube dimensions.

Round Plugs

The hollow construction allows these plugs to compress for a snug fit in threaded and unthreaded holes.

Antistatic Round Plugs

Keep equipment safe from electrical currents with these plugs that have a surface resistivity of less than 10¹² ohms.

Threaded Round Plugs for Straight-Thread Pipe

Seal tube and hose fittings to keep their straight threads protected from contaminants during fabrication and storage.

High-Temperature Round Plugs for NPT Pipe

These plugs withstand temperatures up to 600° F to protect internally threaded NPT connections from contaminants during electropainting, paint baking, and powder coating applications.

Threaded Round Plugs for 37° Flared Tube

Designed to fit into 37° flared connections such as those found on JIC and SAE fittings, these plugs protect internally threaded connections from contaminants during fabrication and storage.

Threaded Round Plugs for BSPT Pipe

Safeguard internally threaded BSPT connections from contaminants during fabrication and storage.

Threaded Round Plugs for NPT Pipe

Protect internally threaded NPT connections from contaminants during fabrication and storage.

Pull-Tab Round Plugs

A time-saving alternative to threaded plugs, these plugs press in place and have an ergonomic pull tab for quick and easy removal. Use them to temporarily protect holes in objects from contaminants during storage, painting, and light fabrication.

Flanged Pull-Through Round Plugs

Designed with a flange, these plugs protect countersunk holes during anodizing, electroplating, paint baking, and powder-coating applications. All withstand temperatures up to 600° F. Use the smaller end of the plug to pull the larger end into a through hole to form a tight seal.

Chemical-Resistant Pull-Through Round Plugs

These plugs have excellent chemical resistance for masking parts during chemical finishing applications such as plating and anodizing. Use the smaller end of the plug to pull the larger end into a through hole to form a tight seal.

Miniature Pull-Through Round Plugs

Also known as mouse tails, these tiny plugs fit through-hole IDs as small as 0.022”, 0.025", or 0.03”.

High-Temperature Pull-Through Round Plugs

Good for electroplating, paint baking, and powder-coating applications, these plugs withstand temperatures up to 600° F. To form a tight seal, use the smaller end of the plug to pull the larger end into a through hole.

Tapered Plugs

Hollow Tapered Plugs

The hollow construction allows these plugs to compress for a snug fit in threaded and unthreaded holes of varying diameters.

Hollow Tapered Plug Assortments

Keep hollow tapered plugs of various sizes on hand to solve whatever problems arise. The hollow construction allows these plugs to compress for a snug fit in threaded and unthreaded holes of varying diameters.

Corks

Lightweight and moisture resistant, these plugs are laboratory-grade 100% natural cork. They’re tapered to fit a range of hole diameters.

Tapered Plugs

Often used as laboratory stoppers, these rubber plugs have good impact and abrasion resistance. They’re tapered to fit a range of hole diameters.

Miniature Tapered Plugs

Sized to fit small openings, these tiny plugs fit snugly but can be removed easily using the flange. Their tapered design fits a range of hole diameters.

Expandable Tapered Plugs

Place a plug into an opening and tighten the wing nut—the sides expand to create a seal in holes of varying diameters.

Tamper-Evident Tapered Plugs

Often used on gas cylinders, these plugs cinch and lock tightly around valve heads to block the ports—they must be cut off making it clear if the cylinder has been tampered with. The plugs are tapered to fit a range of hole diameters.

Pull-Ring Tapered Plugs

Pull the two built-in rings to quickly remove these plugs. All are tapered to fit a range of hole diameters.

Hollow High-Temperature Tapered Plugs

The hollow construction allows these plugs to compress for a snug fit in threaded and unthreaded holes of varying diameters. Good for electroplating, paint baking, and powder-coating applications, they withstand temperatures up to 450° F.

High-Temperature Tapered Plugs

Good for electroplating, paint baking, and powder-coating applications, these plugs withstand temperatures up to 570° F. All are tapered to fit a range of hole diameters.

Miniature High-Temperature Tapered Plugs

Sized to fit small openings, these tiny plugs fit snugly but can be removed easily using the flange. They withstand temperatures up to 470° F, which makes them good for electroplating, paint baking, and powder-coating applications. All are tapered to fit a range of hole diameters.

Expandable High-Temperature Tapered Plugs

Place a plug into an opening and tighten the wing nut—the sides expand to create a seal in holes of varying diameters. Good for paint baking and powder-coating applications, these plugs withstand temperatures up to 450° F.

Food Industry Tapered Plugs

Made of FDA listed materials, these plugs are suitable for food contact. They're tapered to fit a range of hole diameters.

Chemical-Resistant Tapered Plugs

These plugs have excellent chemical resistance for masking parts during chemical finishing applications such as plating and anodizing. Their tapered design fits a range of hole diameters.

Panel Plugs

Plastic Snap-In Panel Plugs

Tapered prongs or a snap-in ring securely hold these plugs in place.

Metal Snap-In Panel Plugs

Made of steel, these are our most durable plugs for panels. Tapered prongs snap into the hole to securely hold them in place.

Metal Snap-In Panel Plug Assortments

Keep metal snap-in plugs of various sizes on hand to solve whatever problems arise. Made of steel, these plugs are our most durable plugs for panels. Their tapered prongs snap into holes to securely hold them in place.

Vented Snap-In Panel Plugs

Vents in the top allow air circulation and permit heat and fumes to escape. These plugs have tapered prongs that snap into the hole to securely hold them in place.

Vented Locking Panel Plugs

Vents in the top allow air circulation and permit heat and fumes to escape. All of these plugs have wings that expand against the sides of the hole to lock them in place.

Push-In Panel Plugs

Push these plugs into place for a finished appearance on both sides of a panel.

Clear Locking Panel Plugs

These plugs are see-through to provide visibility and light transmission. They have wings that expand against the sides of the hole to lock them in place.

Sealing Panel Plugs

The wings on these plugs expand against the sides of a hole to form a liquid-tight seal. Pierce the plugs with round wire, cable, or tubing and they function as a grommet to create insulated holes.

Locking Panel Plugs

The wings on these plugs expand against the sides of a hole to lock them in place.

Expansion Plugs for Castings

Also known as freeze plugs, these are commonly used to permanently seal the shallow holes left in a component during the casting process.

Hydraulic Sealing Plugs

Permanently seal unthreaded holes in pneumatic and hydraulic components.

Caps

Squeeze Top Caps

Squeeze the dome top to remove these caps. They're commonly used as thread protectors.

Metal Round Caps

More durable than plastic caps, these provide the most protection from abrasion and impact.

Heavy Duty Round Caps

Made of rigid plastic, these caps are more wear resistant than vinyl caps but not as flexible.

Round Caps

Slide these flexible vinyl caps on and they conform for a snug fit.

Domed Round Caps

The large domed head extends beyond the diameter of your pipe, rod, or tubing for added protection.

Roll-Resistant Round Caps

Commonly used on shipping tubes, these caps have a square head to prevent round objects from rolling during shipping and storage.

Hanging Round Caps

Slide these caps over a tool handle or other round object and use the eye to hang it.

Tethered Round Caps

The tethered design allows frequent access to the ends of pipe, tubing, and other round objects without ever misplacing the cap.

Sure-Grip Round Caps

A long, textured pull tab provides a sure grip for quick removal even when wearing gloves.

Antistatic Round Caps

Keep equipment safe from electrical currents with these caps that have a surface resistivity of less than 10¹² ohms.

Conductive Round Caps

With a surface resistivity of less than 10⁵ ohms, these caps not only dissipate electrical charges, but can be used as an electrical shield.

High-Temperature Round Caps

Good for electroplating, paint baking, and powder-coating applications, these caps withstand temperatures up to 440° F or 570° F.

Chemical-Resistant Round Caps

These caps have excellent chemical resistance for masking parts during chemical finishing applications such as plating and anodizing.

Food Industry Round Caps

Made of FDA listed materials, these caps are suitable for food contact.

Tapered Cap Assortments

Keep tapered caps of various sizes on hand to solve whatever problems arise. These flexible plastic caps are tapered to fit a variety of unthreaded and threaded objects.

Tapered Caps

These flexible plastic caps are tapered to fit a variety of unthreaded and threaded objects.

High-Temperature Tapered Caps

Made of silicone, these caps withstand temperatures of 450° F for electroplating, paint-baking, and powder-coating applications. All of these flexible caps are tapered to fit a variety of unthreaded and threaded objects.

High-Visibility Pull-Tab Caps

A vibrant yellow color makes these caps stand out. They are made of flexible rubber that conforms for a snug fit. Pull the tab for easy removal.

Flexible Pull-Tab Caps

Slide these flexible vinyl caps on and they conform for a snug fit. Pull the tab for easy removal.

Tear-Tab Caps

Push these caps onto pipe and fittings, then tear their tab to break the seal for easy removal.

Propane Tank Tear-Tab Caps

Designed for propane tanks such as those on forklifts and grills, these caps protect tank valves during storage and transit. Push the caps onto the valves, then tear their tab to break the seal for easy removal.

Heat-Shrink Round Caps

Permanently seal pipe, tubing, conduit, and even crimped electrical connections. Slide these flexible caps on and use a heat gun to tightly shrink them to the shape of whatever they are covering. Their outer surface shrinks while the inner wall flows into voids to create a sealed connection.

Threaded Caps

Protect externally threaded components from contaminants during fabrication and storage.

Stretchable Sealing Caps

Tug on the pull tabs to stretch these caps onto the tips of bottles, beakers, flasks, and cylinders, creating an airtight seal.

Adhesive-Back Flange Caps

Stick these caps on the raised surfaces of flanges or other flat surfaces for extra protection during transport and storage.

Flange Caps

Snap these caps into flange bolt holes to safeguard pipe flanges during shipping, storing, and finishing applications. They all have a thick center pad to protect the flange opening and pipe threads from damage.

Stretchable Flange Caps

Stretch these caps over flared edges such as flanged tubing and valve handles.

Rebar Caps

Keep personnel safe from protruding rebar and pipe. Made of rigid plastic, these durable safety caps are bright orange or yellow for excellent visibility.

Screw Caps

Conceal and protect the tops of socket head or button head screws.

Snap-On Fastener Caps

To conceal and protect the entire screw head, insert your screw through the hole in the base and snap on the top.

Hinged Fastener Caps

A one-piece hinged design allows frequent access to screw heads without misplacing the top. To conceal and protect the entire screw head, insert your screw through the hole in the base and flip the hinged top over.

Tube-End Nuts

Tube-Connecting Nuts

Create strong joints in round tubes.

Tube-End Weld Nuts

About half the strength of medium-strength steel coupling nuts, these metric nuts are for light duty fastening applications.

Left-Hand Threaded Tube-End Weld Nuts

Use these tube-end weld nuts with left-hand threaded fasteners.

Leveling Mount Inserts for Tubular Legs

Metric High-Capacity Leveling
Mount Inserts for Tubular Legs

Rated for high load capacity, use these metric inserts to connect threaded leveling mounts to heavy equipment.

Leveling Mount Inserts for Tubular Legs

Slip these inserts into tubular legs to quickly add threads for attaching leveling mounts. They’re often used in the legs of light equipment and furniture.

High-Capacity Leveling Mount Inserts for Tubular Legs

Rated for high load capacity, use these inserts to connect threaded leveling mounts to heavy equipment.

Leveling Mounts for Tubular Legs

Insert these adjustable mounts into tube ends to level your equipment in a single step.