Square Drive Plugs | McMaster-Carr

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73 Products

About Tapping Screws

How to Identify and Measure Fittings

Pipe size is an industry designation, not the actual size. View information about how to measure threaded and unthreaded pipe and pipe fittings.

Low-Pressure Iron and Steel Threaded Pipe Fittings

Use these fittings for low-pressure applications in noncorrosive environments.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Presure Class:
Steel: 150
Iron: 125
Pipe Nipples and Pipe: Use Schedule 40 steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material		Each
1/8	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	00000
1/4	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	000
3/8	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	000
1/2	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	000
3/4	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	000
1	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	0000
1 1/4	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	0000
1 1/2	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	00000
2	Solid	150 psi @ 72° F	150 psi @ 350° F	Steel	000000000	00000
2 1/2	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
3	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
3 1/2	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
4	Hollow	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	000000

Low-Pressure Iron and Steel Threaded Pipe Fittings with Sealant

To prevent leaks in low-pressure lines, the male threads on these fittings have an acrylic sealant already applied for extra protection. Also known as Pressure Class 125 or 150 fittings. Made of either iron or steel, they’re best in noncorrosive environments. Even with sealant, threaded connections can be taken apart for maintenance and repair.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Diesel Fuel, Gasoline, Natural Gas, Oil, Water
Pressure Class: 150
Specifications Met: See table
Pipe Nipples and Pipe: Use Schedule 40 Iron and Steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Material	Specifications Met		Each
1/2	Solid	150 psi @ 72° F	Steel	SAE J531	0000000	00000
3/4	Solid	150 psi @ 72° F	Steel	SAE J531	0000000	0000
1	Solid	150 psi @ 72° F	Steel	SAE J531	0000000	0000
1 1/4	Solid	150 psi @ 72° F	Steel	ASME B16.14	0000000	0000
2	Solid	150 psi @ 72° F	Steel	ASME B16.14	0000000	00000

FM-Approved Low-Pressure Cast Iron Threaded Pipe Fittings

Suitable for use in fire-protection applications, these pipe fittings are made of cast iron, so they are brittle and can be quickly opened with the strike of a sledge hammer. They are also known as Pressure Class 125 fittings. Use in noncorrosive environments.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class: 125
Specifications Met: FM Approved, UL Listed, ASTM A126, ASME B1.20.1, ASME B16.4
Pipe Nipples and Pipe: Use Schedule 40 steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material		Each
1	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	000000
1 1/4	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
1 1/2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
2 1/2	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
3	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	00000
4	Solid	175 psi @ 72° F	125 psi @ 350° F	Iron	000000000	000000

Low-Pressure Galvanized Iron and Steel Threaded Pipe Fittings

The galvanized finish on these fittings provides fair corrosion resistance. Fittings are for use in low-pressure applications.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Steam, Oil, Water, Natural Gas
Pressure Class: 150
Specifications Met: SAE J531
Pipe Nipples and Pipe: Use Schedule 40 steel
Flanges: Use Class 150 galvanized steel

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure	Material		Each
1/8	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	00000
1/4	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	000
3/8	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	000
1/2	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	000
3/4	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	000
1	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	0000
1 1/4	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	0000
1 1/2	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	00000
2	Solid	150 psi @ 72° F	150 psi @ 350° F	Galvanized Steel	00000000	00000

Low-Pressure Galvanized Iron and Steel Threaded Pipe Fittings with Sealant

The male threads on these fittings have a sealant applied for extra leak protection. Fittings are made of galvanized iron or steel, which have fair corrosion resistance. Also known as Pressure Class 125 or 150 fittings, they are for use in low-pressure applications.

NPTF (Dryseal) threads are compatible with NPT threads.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Oil, Natural Gas, Steam, Water
Pressure Class: 150
Specifications Met: SAE J531
Pipe Nipples and Pipe: Use Schedule 40 galvanized steel
Flanges: Use Class 150 galvanized steel

NPTF Male
Pipe Size	Plug Construction	Max. Pressure	Max. Steam Pressure		Each
1/8	Solid	150 psi @ 72° F	150 psi @ 360° F	0000000	00000
1/4	Solid	150 psi @ 72° F	150 psi @ 360° F	0000000	000
3/8	Solid	150 psi @ 72° F	150 psi @ 360° F	0000000	000
1/2	Solid	150 psi @ 72° F	150 psi @ 360° F	0000000	000
3/4	Solid	150 psi @ 72° F	150 psi @ 360° F	0000000	000
1	Solid	150 psi @ 72° F	150 psi @ 360° F	0000000	0000

Low-Pressure Brass and Bronze Threaded Pipe Fittings

Use these fittings in low-pressure flow applications. They have good corrosion resistance. Fittings rated for use with drinking water meet NSF/ANSI 61 safety standards.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Drinking Water, Natural Gas, Oil
Pressure Class: 125
Specifications Met:
NPT: ASME B1.20.1, ASME B16.15, NSF/ANSI 61
BSPT: ASME B16.15, ASME BS21, ASTM B584, NSF/ANSI 61
Pipe Nipples and Pipe: Use Schedule 40 brass
Flanges: Use Class 150 brass

NPT Male
Pipe Size	Plug Construction	Max. Pressure	Material		Each
1/2	Solid	200 psi @ 72° F	Brass	00000000	000000
3/4	Solid	200 psi @ 72° F	Brass	00000000	00000
1	Solid	200 psi @ 72° F	Brass	00000000	00000
1 1/4	Solid	200 psi @ 72° F	Brass	00000000	00000
1 1/2	Solid	200 psi @ 72° F	Brass	00000000	00000
2	Solid	200 psi @ 72° F	Brass	00000000	00000
2 1/2	Solid	200 psi @ 72° F	Brass	00000000	000000
3	Solid	200 psi @ 72° F	Brass	00000000	000000
4	Solid	200 psi @ 72° F	Brass	00000000	000000
BSPT Male
3/4	Solid	200 psi @ 72° F	Brass	00000000	00000
1	Solid	200 psi @ 72° F	Brass	00000000	00000
1 1/2	Solid	200 psi @ 72° F	Brass	00000000	00000
2	Solid	200 psi @ 72° F	Brass	00000000	00000

Low-Pressure Brass Threaded Pipe Fittings with Sealant

The male threads on these fittings have a sealant applied for extra protection against leaks. Also known as Pressure Class 125 fittings, they are built for use in low-pressure applications. They are brass for good corrosion resistance.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Drinking Water, Natural Gas, Oil, Water
Pressure Class: 125
Pipe Nipples and Pipe: Use Schedule 40 brass
Flanges: Use Class 150 brass

NPT Male
Pipe Size	Plug Construction	Max. Pressure		Each
1/2	Solid	200 psi @ 72° F	0000000	000000
3/4	Solid	200 psi @ 72° F	0000000	00000
1	Solid	200 psi @ 72° F	0000000	00000
1 1/4	Solid	200 psi @ 72° F	0000000	00000
1 1/2	Solid	200 psi @ 72° F	0000000	00000
2	Solid	200 psi @ 72° F	0000000	00000

Low-Pressure Aluminum Threaded Pipe Fittings

In addition to being lightweight, these aluminum fittings offer good corrosion resistance. Use them in low-pressure flow applications. To prevent cracking, do not tighten more than a 1/4-turn past hand tight.

For technical drawings and 3-D models, click on a part number.

Plugs with Square Drive

For Use With: Air, Oil, Water
Pressure Class: 150
Pipe Nipples and Pipe: Use Schedule 40 aluminum
Flanges: Use Class 125 aluminum

NPT Male
Pipe Size	Plug Construction	Max. Pressure		Each
3/8	Solid	150 psi @ 72° F	000000000	00000
1/2	Solid	150 psi @ 72° F	000000000	0000
3/4	Solid	150 psi @ 72° F	000000000	00000
1	Solid	150 psi @ 72° F	000000000	00000
1 1/4	Solid	150 psi @ 72° F	000000000	00000
1 1/2	Solid	150 psi @ 72° F	000000000	00000
2	Solid	150 psi @ 72° F	000000000	00000
2 1/2	Solid	150 psi @ 72° F	000000000	00000
3	Solid	150 psi @ 72° F	000000000	00000
4	Solid	150 psi @ 72° F	000000000	000000

Sealing Screws for Softwood and Plastic-Wood Composites

The neoprene-backed washer seals out contaminants. Also known as trim-head deck screws, they have a small flat head and slender shank to reduce the risk of splitting. They have a Type 17 auger point to penetrate softwood and plastic-wood composite decking material. Made from 18-8 stainless steel, they have good chemical resistance and are a good choice for ACQ-treated (arsenic-free) lumber. Screws may be mildly magnetic. Length is measured from the top of the head.

For technical drawings and 3-D models, click on a part number.

	Head		Washer
Lg.	Dia.	Ht.	OD	Thick.	Drive Size	Drill Bit Size	Approximate Threads per Inch	Threading	Min. Thread Lg.	Pkg. Qty.		Pkg.
18-8 Stainless Steel
No. 7
1"	0.23"	0.125"	0.63"	0.2"	No. 1	1/16"	16	Partially Threaded	7/8"	25	000000000	000000
1 5/8"	0.23"	0.125"	0.63"	0.2"	No. 1	1/16"	16	Partially Threaded	1 1/8"	25	000000000	00000
2 1/4"	0.23"	0.125"	0.63"	0.2"	No. 1	1/16"	16	Partially Threaded	1 1/4"	10	000000000	00000
3"	0.23"	0.125"	0.63"	0.2"	No. 1	1/16"	16	Partially Threaded	2"	10	000000000	00000