6-40 Screws | McMaster-Carr

More corrosion resistant than 18-8 stainless steel screws, these screws have excellent resistance to chemicals and salt water. They may be mildly magnetic.

Alloy Steel Cup-Point Set Screws

Made from alloy steel, these inch size set screws have a thin edge that digs into hard surfaces for a secure hold.

18-8 Stainless Steel Cup-Point Set Screws

Made from 18-8 stainless steel, these set screws have good chemical resistance.

Alloy Steel Knurl-Grip Cup-Point Set Screws

Made from black-oxide alloy steel, these set screws resist corrosion in dry environments. They dig into hard surfaces for a secure hold and have serrations on the cup edge that grip the material surface to resist loosening.

Plastic Flat-Tip Set Screws

These nylon set screws are chemical resistant, lightweight, and nonconductive. The tip makes good contact on flat surfaces and allows you to make frequent adjustments with minimal surface damage.

Alloy Steel Cone-Point Set Screws

These alloy steel set screws have a pointed tip that wedges into the contact surface for a secure hold on soft materials such as brass.

Alloy Steel Hollow-Lock Set Screws

Also known as jam set screws, these lock other screws in place, hold pins, and adjust spring tension. A black-oxide finish provides corrosion resistance in dry environments.

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-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.

Ball-Nose Spring Plungers

Slotted Ball-Nose Spring Plungers

Install these spring plungers with a screwdriver—they're slotted on one or both ends.

Hex-Drive Ball-Nose Spring Plungers

Install with a hex key for more torque than slotted ball-nose spring plungers.

Center-Locating Punches for Threaded Holes

Also known as transfer screws, these punches have a uniform shoulder height so you can quickly transfer multiple hole locations at once.