5/16"-18 Adapters | McMaster-Carr

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

REACH Compliant

	Installed Length Installed Length

	Threaded Insert Type Threaded Insert Type


Thread Locking	Key Locking

	Pitch Pitch

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447 Products

Low-Profile Hex Manifolds

When you’re short on vertical space, these manifolds are a good fit—they have outlets on the side instead of on top, so they have a lower profile than rectangular manifolds. Use them to distribute air or fluid to five locations from a single supply source.

Thread Adapters

Inch-to-Inch Male-Female Hex Thread Adapters

Join threads with small diameters to large or course threads to fine with these inch-sized adapters.

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-NPT Male-Female Hex
Thread Adapters with Through Hole

The through hole allows you to connect float rods to float valves.

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-Metric Male Hex Thread Adapters

One side inch, one side metric, and a hex in the middle—these handy fasteners connect two female-threaded parts, such as coupling nuts, adapting from inch threads to metric. Tighten with a standard wrench.

Left-Hand to Right-Hand Male Thread Adapters

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.

Left-Hand to Right-Hand Female Hex Thread Adapters

Often called sleeve nuts, these thread adapters fasten parts with right-hand threads to parts with left-hand threads.

Easy-to-Install Thread-Locking Inserts for Metal

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.

316 Stainless Steel Easy-to-Install
Thread-Locking Inserts

These inserts are the most corrosion-resistant thread-locking inserts we offer.

Easy-to-Install Thread-Locking Insert Assortments

These assortments include various sizes of thread-locking inserts.

Easy-to-Install Thread-Locking
Inserts with Installation Tools

A closed-end tap, drill bit, and installation bit are included with these inserts.

Screw-Locking Easy-to-Install Thread-Locking Inserts

Adhesive on both the internal and external threads keeps these inserts in place and holds screws tight.

Key-Locking Inserts for Soft Metal

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. Alloy Steel Key-Locking Inserts

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

Mil. Spec. Stainless Steel Key-Locking Inserts

These inserts are made to stringent military specifications.

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.

Key-Locking Insert Assortments with Installation Tool

Screw-Locking Key-Locking Inserts

With a distorted internal thread and keys on the outside, these inserts create a strong hold on both fasteners and surrounding material.

Threaded Rods and Studs

Hex Drive Threaded Rods

A hex drive on one end allows these rods to be turned with a hex key for ease of installation.

Stainless Steel Wood Screw Threaded Studs

18-8 stainless steel studs have good chemical resistance and may be mildly magnetic. Also known as hanger bolts, use them to hang, mount, and fasten parts to wood structures.

Steel Wood Screw Threaded Studs

These studs are also known as hanger bolts—use them to hang, mount, and fasten parts to wood structures.

Tube-Connecting Nuts

Create strong joints in round tubes.

Threaded Adapters for Pullers

Use adapters on the ends of forcing screws and face-grip puller legs when pulling shafts, bearing caps, and pinions.

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.

Large-Cell Batteries

Battery Terminal Fasteners

Replace battery terminal hardware.