1/4"-28 Reducers | McMaster-Carr

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	System of Measurement System of Measurement

Inch

Metric

	Thread Size Thread Size	Show

1/4"-28

	Thread Size Thread Size	Hide

	Thread Type Thread Type

NPT

UN/UNF (SAE Straight)

UNF

UNJF

	Material Material

	Gender Gender

Female

Male

	Type Type


Bushing	Reducing Adapter

	Threaded Insert Type Threaded Insert Type


Thread Locking	Key Locking

Helical	Heat Set

Tapping

	Hex Length Hex Length

	Shape Shape


Straight	Hex

	Installed Length Installed Length

	Specifications Met Specifications Met

	For Tap Thread Size For Tap Thread Size

	RoHS (Restriction of Hazardous Substances) RoHS (Restriction of Hazardous Substances)

RoHS Compliant

RoHS Compliant with
Exemptions

	Thread Length Thread Length

	DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense Acquisition Regulations Supplement)

DFARS Specialty Metals
COTS-Exempt

DFARS Specialty Metals
Compliant

	Tensile Strength Tensile Strength

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

REACH Compliant

	Thread Fit Thread Fit

	For Adapting For Adapting

Gender

Thread Size

	Hex Size Hex Size

	Pipe Size Pipe Size

1/8

1/4

	Drive Style Drive Style


External Hex	Hex	Slotted

	Hardness Hardness

248 Products

Metal Pipe and Pipe Fittings

Miniature Medium-Pressure Stainless
Steel Threaded Pipe Fittings

When space is at a premium choose these compact fittings.

Miniature Medium-Pressure
Aluminum Threaded Pipe Fittings

Their small size makes these miniature fittings a good choice for cramped, confined spaces.

Thread Adapters

Inch-to-Inch Male-Female Hex Thread Adapters

Change thread sizes or types, such as fine to coarse threads, on parts without changing gender.

Inch-to-Metric Male-Female Hex Thread Adapters

Change inch threads to metric with these adapters, or swap metric threads for inch. An external hex lets you tighten or loosen them with a wrench.

Inch-to-Inch Male Hex Thread Adapters

Need to join two female-threaded parts, such as coupling nuts, with dissimilar inch thread sizes? Attach them to these adapters and tighten the exterior hex nut for a secure connection.

Inch-to-Inch Female Hex Thread Adapters

Connect two differently sized male-threaded parts, such as threaded rods, and tighten with a standard wrench.

Inch-to-Metric Female Hex Thread Adapters

Adapt threaded rods from inch to metric. These adapters connect two male-threaded fasteners, so you can change the gender of a mating part or increase or decrease its thread size. The hex-shaped body fits into the head of a standard wrench.

Threaded Inserts

18-8 Stainless Steel Easy-to-Install
Thread-Locking Inserts

Made of 18-8 stainless steel, these inserts have better corrosion resistance than black-phosphate steel.

Black-Phosphate Steel Easy-to-Install
Thread-Locking Inserts

A black-phosphate finish provides mild corrosion resistance.

Easy-to-Install Thread-Locking Insert Assortments

These assortments include various sizes of thread-locking inserts.

18-8 Stainless Steel Key-Locking Inserts

Made of 18-8 stainless steel, these inserts have good corrosion resistance.

Black-Phosphate Steel Key-Locking Inserts

A black-phosphate finish provides mild corrosion resistance.

Mil. Spec. Stainless Steel Key-Locking Inserts

These inserts are made to stringent military specifications.

Mil. Spec. Alloy Steel Key-Locking Inserts

The strongest key-locking inserts we offer, these inserts are made to stringent military specifications.

Key-Locking Insert Assortments with Installation Tool

Key-Locking Inserts with Installation Tool

These inserts come with an installation tool. Drive the keys into the surrounding material for a more secure hold than thread-locking inserts.

Screw-Locking Key-Locking Inserts

Forming the strongest hold of any of our threaded inserts, these inserts have a distorted internal thread to lock screws into place and keys that drive into surrounding material to prevent slipping and rotating.

Stainless Steel Helical Inserts

Stainless Steel Screw-Locking Helical Inserts

A distorted thread grips the screw to resist loosening.

Stainless Steel Helical Inserts without Prong

Without a prong to break off and retrieve, these inserts are often used where debris could cause damage.

Helical Inserts with Installation Tools

Inserts come with a through-hole tap and installation tool.

Helical Insert Assortments with Installation Tools

Assortments include various sizes of helical inserts and a tap, a drill bit, and an installation tool for each thread size.

Tapered Heat-Set Inserts for Plastic

The tapered shape makes it easier to guide these inserts into a hole during installation. Use a drill bit to create a straight hole, then taper the top half.

Heat-Set Inserts for Plastic

Install these inserts into plastic parts to create a secure base for fasteners.

Stainless Steel Tapping Inserts for Hardwood

These 18-8 stainless steel inserts have excellent resistance to chemicals and may be mildly magnetic.

Brass Tapping Inserts for Hardwood

Made from brass, these inserts are nonmagnetic, mildly corrosion resistant, and electrically conductive.

Nuts

Steel Twist-Resistant Rivet Nuts

About twice as strong as aluminum rivet nuts, these steel rivet nuts are zinc plated for mild corrosion resistance.

Steel Low-Profile Rivet Nuts

About twice as strong as aluminum rivet nuts, these low-profile rivet nuts have a cadmium or tin-zinc plating for corrosion resistance.

Aluminum Low-Profile Rivet Nuts

These low-profile rivet nuts are one-third the weight of steel and have mild corrosion resistance.

Stainless Steel Low-Profile Rivet Nuts

The most corrosion resistant low-profile rivet nuts we offer, these stand up to chemicals.

Alloy Steel Socket Nuts

Stronger than stainless steel, these nuts are comparable in strength to Grade 9 bolts.

Metal Pipe and Pipe Fittings

Miniature Medium-Pressure StainlessSteel Threaded Pipe Fittings

Miniature Medium-PressureAluminum Threaded Pipe Fittings

Thread Adapters

Inch-to-Inch Male-Female Hex Thread Adapters

Inch-to-Metric Male-Female Hex Thread Adapters

Inch-to-Inch Male Hex Thread Adapters

Inch-to-Inch Female Hex Thread Adapters

Inch-to-Metric Female Hex Thread Adapters

Threaded Inserts

18-8 Stainless Steel Easy-to-InstallThread-Locking Inserts

Black-Phosphate Steel Easy-to-InstallThread-Locking Inserts

Easy-to-Install Thread-Locking Insert Assortments

18-8 Stainless Steel Key-Locking Inserts

Black-Phosphate Steel Key-Locking Inserts

Mil. Spec. Stainless Steel Key-Locking Inserts

Mil. Spec. Alloy Steel Key-Locking Inserts

Key-Locking Insert Assortments with Installation Tool

Key-Locking Inserts with Installation Tool

Screw-Locking Key-Locking Inserts

Stainless Steel Helical Inserts

Stainless Steel Screw-Locking Helical Inserts

Stainless Steel Helical Inserts without Prong

Helical Inserts with Installation Tools

Helical Insert Assortments with Installation Tools

Tapered Heat-Set Inserts for Plastic

Heat-Set Inserts for Plastic

Stainless Steel Tapping Inserts for Hardwood

Brass Tapping Inserts for Hardwood

Nuts

Steel Twist-Resistant Rivet Nuts

Steel Low-Profile Rivet Nuts

Aluminum Low-Profile Rivet Nuts

Stainless Steel Low-Profile Rivet Nuts

Alloy Steel Socket Nuts

Miniature Medium-Pressure Stainless
Steel Threaded Pipe Fittings

Miniature Medium-Pressure
Aluminum Threaded Pipe Fittings

18-8 Stainless Steel Easy-to-Install
Thread-Locking Inserts

Black-Phosphate Steel Easy-to-Install
Thread-Locking Inserts