2-56 Reducers | McMaster-Carr

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	System of Measurement System of Measurement

Inch

Metric

	Thread Size Thread Size	Show

2-56

	Thread Size Thread Size	Hide

	Material Material

	Threaded Insert Type Threaded Insert Type


Key Locking	Helical

Press Fit	Heat Set

Tapping

	Hex Length Hex Length

	For Use In For Use In

Metal

Plastic

	Installed Length Installed Length

Less than 0.25"

0.25" to 0.499"

	Specifications Met Specifications Met

	Helical Insert Style Helical Insert Style

With Prong

Without Prong

	Hex Size Hex Size

	Thread Length Thread Length

	Tensile Strength Tensile Strength

	Gender Gender

Female

Male

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

RoHS Compliant

RoHS Compliant with
Exemptions

	For Minimum Material Thickness For Minimum Material Thickness

Less than 0.25"

0.25" to 0.499"

	For Maximum Hole Diameter For Maximum Hole Diameter

Less than 0.25"

Less than 5 mm

	Shape Shape

	Hex

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

DFARS Specialty Metals
COTS-Exempt

DFARS Specialty Metals
Compliant

	Thread Fit Thread Fit

	Drill Bit Size Drill Bit Size

	For Adapting For Adapting

Gender

Thread Size

	Drive Style Drive Style

	External Hex

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

REACH Compliant

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155 Products

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 for Metal

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.

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 Helical Inserts
for Particle-Free Environments

Made of Nitronic 60 stainless steel, these inserts prevent the screw from binding or sticking without any coating or lubricant that could contaminate particle-free environments.

Lubricated Stainless Steel Helical Inserts

A dry film keeps the screw from sticking or binding in these inserts during installation.

Lubricated Stainless Steel Helical
Inserts for Dissimilar Metals

Eliminating the need for primer, these inserts are coated to resist corrosion when installed in different materials.

Nickel Alloy Helical Inserts

Made of nickel alloy, these inserts are more resistant to acids and salt water than stainless steel inserts.

Stainless Steel Screw-Locking Helical Inserts

A distorted thread grips the screw to resist loosening.

Stainless Steel Screw-Locking Helical
Inserts for Particle-Free Environments

Made of Nitronic 60 stainless steel, these inserts prevent the screw from binding or sticking without any coating or lubricant that could contaminate particle-free environments.

Lubricated Stainless Steel Screw-Locking Helical Inserts

A dry film keeps the screw from sticking or binding in these inserts during installation.

Stainless Steel Helical Inserts without Prong

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

Lubricated Stainless Steel Helical Inserts without Prong

A dry film keeps the screw from sticking or binding in these inserts during installation.

Screw-Locking Helical Inserts without Prong

A distorted thread grips the screw to resist loosening.

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.

Press-Fit Inserts for Soft Metal

The knurled body holds these inserts in place in aluminum and other soft metals. Use an arbor press to install them in untapped holes.

Threaded Inserts for Plastic

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.

18-8 Stainless Steel Screw-to-Expand Inserts for Plastic

These 18-8 stainless steel inserts have better corrosion resistance than brass inserts and may be mildly magnetic.

Brass Screw-to-Expand Inserts for Plastic

Made from brass, these inserts are electrically conductive, nonmagnetic, and have good corrosion resistance.

Aluminum Screw-to-Expand Inserts for Plastic

These aluminum inserts are 70% lighter than brass inserts, electrically conductive, and nonmagnetic. They have good corrosion resistance, which is comparable to brass but not as good as stainless steel.

Brass Flanged Screw-to-Expand Inserts for Plastic

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

Aluminum Flanged Screw-to-Expand Inserts for Plastic

18-8 Stainless Steel Flanged
Screw-to-Expand Inserts for Plastic

These 18-8 stainless steel inserts have better corrosion resistance than brass inserts and may be mildly magnetic.

Screw-to-Expand Inserts for Through Holes in Plastic

The flange keeps these inserts from pulling through a hole. Press them in from the underside of material, and install a screw from the top of material.

Aluminum Twist-Resistant Hex-Shaped Inserts for Plastic

70% lighter than stainless steel, these aluminum inserts are mildly corrosion resistant and nonmagnetic.

18-8 Stainless Steel Twist-Resistant
Hex-Shaped Inserts for Plastic

These 18-8 stainless steel inserts have better corrosion resistance than aluminum inserts and may be mildly magnetic.

Heat-Set Inserts for Plastic

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

Barbed Inserts for Plastic

The barbed sides keep these securely in place even before a screw is installed.

Tapping Inserts for Plastic

Also known as Trisert inserts, these cut threads into plastic and have better holding power than press-fit inserts.

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 for Metal

Mil. Spec. Stainless Steel Key-Locking Inserts

Mil. Spec. Alloy Steel Key-Locking Inserts

Screw-Locking Key-Locking Inserts

Stainless Steel Helical Inserts

Stainless Steel Helical Insertsfor Particle-Free Environments

Lubricated Stainless Steel Helical Inserts

Lubricated Stainless Steel HelicalInserts for Dissimilar Metals

Nickel Alloy Helical Inserts

Stainless Steel Screw-Locking Helical Inserts

Stainless Steel Screw-Locking HelicalInserts for Particle-Free Environments

Lubricated Stainless Steel Screw-Locking Helical Inserts

Stainless Steel Helical Inserts without Prong

Lubricated Stainless Steel Helical Inserts without Prong

Screw-Locking Helical Inserts without Prong

Helical Inserts with Installation Tools

Helical Insert Assortments with Installation Tools

Press-Fit Inserts for Soft Metal

Threaded Inserts for Plastic

Tapered Heat-Set Inserts for Plastic

18-8 Stainless Steel Screw-to-Expand Inserts for Plastic

Brass Screw-to-Expand Inserts for Plastic

Aluminum Screw-to-Expand Inserts for Plastic

Brass Flanged Screw-to-Expand Inserts for Plastic

Aluminum Flanged Screw-to-Expand Inserts for Plastic

18-8 Stainless Steel FlangedScrew-to-Expand Inserts for Plastic

Screw-to-Expand Inserts for Through Holes in Plastic

Aluminum Twist-Resistant Hex-Shaped Inserts for Plastic

18-8 Stainless Steel Twist-ResistantHex-Shaped Inserts for Plastic

Heat-Set Inserts for Plastic

Barbed Inserts for Plastic

Tapping Inserts for Plastic

Stainless Steel Helical Inserts
for Particle-Free Environments

Lubricated Stainless Steel Helical
Inserts for Dissimilar Metals

Stainless Steel Screw-Locking Helical
Inserts for Particle-Free Environments

18-8 Stainless Steel Flanged
Screw-to-Expand Inserts for Plastic

18-8 Stainless Steel Twist-Resistant
Hex-Shaped Inserts for Plastic