5/16"-18 Nuts | McMaster-Carr

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1,517 Products

Fastening and Joining

Hex Nuts

Handle most general fastening needs

98 products

Locknuts

Hold fasteners in place to prevent loosening from vibration

60 products

Flange Nuts

The flange distributes pressure, so you don't need a washer

37 products

Cap Nuts

Cover and protect threads while adding a finished look; also known as acorn nuts

28 products

Coupling Nuts

Connect and extend threaded rods

27 products

Thumb Nuts

Easy to tighten and loosen by hand for making frequent adjustments

37 products

Square Nuts

Flat sides won’t spin in channels and square holes

11 products

Tamper-Resistant Nuts

Hard to detach without special tools to prevent unwanted removal

12 products

Socket Nuts

Install in recessed holes and tight spots where a wrench won’t fit; also known as Allen nuts

2 products

Push-Button Nuts

Disengage the threads to quickly slide along threaded rods

3 products

Split Nuts

Swivel to attach at any point on a threaded rod for quick installation

1 product

Sealing Nuts

Prevent leaks and block out contaminants with a rubber seal

1 product

Weld Nuts

Weld to metal surfaces to add permanent threads

40 products

Clip-On Nuts

Slide onto the edge of thin panels to create a fastening point

7 products

Rivet Nuts

Add threads to thin panels with access from only one side; also known as blind inserts

45 products

Press-Fit Nuts

Push into drilled or punched holes to add threads to thin panels

8 products

Screw-Mount Nuts

Mount with screws, rivets, and nails to add threads to a surface

6 products

Threaded Inserts

Create new threads or repair stripped threads

212 products

Snap-In Nuts

Push into square holes in thin materials to add bolts for aligning off-center parts

8 products

Dowel Nuts

Form joints in blind holes in wood

4 products

Adhesive-Mount Nuts

Attach threads to material that’s too thin for a threaded insert

10 products

Push Nuts

Press onto threads for a light duty hold that’s faster to install than typical nuts

2 products

Tube-Connecting Nuts

Push inside tubes to join them with a threaded stud instead of welding

7 products

Binding Barrels

Create custom low-profile fasteners with binding barrel posts, caps, and screws

75 products

Thread Adapters

Join threads of a different type, size, and gender

363 products

Studs

Press, weld, or screw in place to add a threaded fastening point

57 products

Thumb Screws

Tighten and loosen by hand without the need for tools

14 products

Hex Head Screws

Used with nuts to create a stronger joint than flat and rounded screws

8 products

Standoffs

Separate, position, or connect components in assemblies

Install and remove blind, solid, hollow, and other types of rivets

1 product

Sockets

Turn fasteners with an external drive style without slipping and damaging the drive

1 product

Building and Machinery Hardware

T-Slotted Framing Fasteners

Secure brackets and other accessories to T-slotted rails

33 products

Strut Channel Nuts

Fasten on threaded rod to connect components to strut channel

17 products

Handle Nuts

Attach to threaded shafts to quickly turn the shafts by hand

3 products

Leveling Mount Inserts

Slip onto equipment and furniture to add threaded-stud leveling feet

6 products

Fabricating and Machining

T-Slot Nuts

Combine with setup studs or bolts to mount fixtures to machine tables

14 products

Fixture Kits

Everything needed to mount workpieces of different sizes to your machine table

2 products

Setup Studs

Secure setup clamps and fixtures to your machine table or assemble heavy machines

36 products

Fixture Clamps

Secure your workpiece to a fixture table so it won't move during machining

4 products

Lathe Chuck Jaw Nuts

Secure jaws to a CNC lathe chuck

1 product

Material Handling

Eye Nuts

Pair with bolts or threaded rod to lift and hang components

4 products

Turnbuckles

Twist the body or end fittings to adjust the length and tension of attached rope and chain

8 products