1/2"-20 Pins | McMaster-Carr

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For Cotter Pin Diameter

3/32"

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52 Products

Steel Cotter-Pin-Locking Hex Head Screws

Partially

Threaded

Secure rotating parts subjected to vibration, such as the wheels on carts and hand trucks. A cotter pin (not included) slides through the hole in the shank of these screws to keep nuts from loosening. They hold stronger than screws with threadlocker and lockwashers, but they aren’t recommended for high-vibration applications because prolonged stress can shear the pin. The head's six flat sides keep wrenches and sockets from slipping and rounding off the drive.

Length is measured from under the head.

Medium-Strength Fastener—Your go-to screws for fastening most machinery and equipment. They have tensile strengths from 90,000 to 120,000 psi.

Cadmium-Plated Steel—The plating reduces friction between the screw and your mounting surface to prevent sticking when you tighten or loosen screws. It also creates a barrier against rust.

		Head
	Lg.	Wd.	Ht.	Hole Dia.	For Cotter Pin Dia.	Threading	Thread Spacing	Tensile Strength, psi	Mil. Spec.	Pkg. Qty.		Pkg.
Medium-Strength Cadmium-Plated Steel







				1/2"-20

				1 3/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-10	1	94622A241	000000


				1 11/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-12	1	94622A242	0000
				1 19/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-14	1	94622A243	0000
				1 27/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-16	1	94622A244	0000
				2 3/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-20	1	94622A245	00000
				2 19/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-24	1	94622A246	00000
				3 3/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-30	1	94622A247	00000
				3 19/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-34	1	94622A248	00000
				4 3/32"	3/4"	19/64"	0.106"	3/32"	Partially Threaded	Fine	120,000	AN8-40	1	94622A249	00000

Single-End Studs with Cotter Pin

Also known as hood pins, these studs have a cotter pin lodged through a drilled hole in the unthreaded portion for light duty holding, such as securing access panels and locking other fasteners.

18-8 Stainless Steel—Stud and cotter pin are 18-8 stainless steel, making them chemical resistant and mildly magnetic.

			Shaft			Cotter Pin
	Lg.	Thread Lg.	Lg.	Dia.	Dia. Tolerance	Lg.	Hole Dia.	Tensile Strength	Hardness		Each
18-8 Stainless Steel







				1/2"-20

				2"	1"	1"	1/2"	-0.005" to 0.005"	2"	0.141"	Not Rated	Rockwell B89	93712A700	00000


				3"	2"	1"	1/2"	-0.005" to 0.005"	3"	0.141"	Not Rated	Rockwell B89	93712A800	0000
				4"	3"	1"	1/2"	-0.005" to 0.005"	4"	0.141"	Not Rated	Rockwell B89	93712A900	00000

Threaded Taper Pins

Tighten the

nut to draw

the pin out of

the hole.

Threads on these pins stick out for easy removal from blind holes. Tighten the hex nut to draw the pin out. Often used for positioning components and securing assemblies, they taper at a uniform rate to fit in tapered holes. For a snug fit, use a tapered drill bit that matches the pin number for inch sizes or the small end diameter for metric sizes. They have slightly rounded edges to aid insertion.

Inch

Length for inch pins measures the unthreaded length of the pin.

12L14 Carbon Steel—12L14 Carbon steel pins have good strength.

18-8 Stainless Steel—18-8 stainless steel pins offer a balance of strength and corrosion resistance. They may be mildly magnetic.

Breaking Strength—Breaking strength is measured as single shear, which is the force required to break the pin into two pieces.

	Thread Lg.	Thread Size	Min. Hardness	Breaking Strength, psi	Pkg. Qty.		Pkg.
12L14 Carbon Steel







	9 Taper Pin—0.589" Large End Diameter

	2"	0.549"	1:48	3/4"	1/2"-20	Rockwell B85	46,500	1	92281A515	00000


	2 1/2"	0.539"	1:48	3/4"	1/2"-20	Rockwell B85	46,500	1	92281A516	0000
	3"	0.529"	1:48	3/4"	1/2"-20	Rockwell B85	46,500	1	92281A517	0000
	3 1/2"	0.518"	1:48	3/4"	1/2"-20	Rockwell B85	46,500	1	92281A518	0000
	4"	0.508"	1:48	3/4"	1/2"-20	Rockwell B85	46,500	1	92281A519	0000
	4 1/2"	0.497"	1:48	3/4"	1/2"-20	Rockwell B85	46,500	1	92281A520	0000
	5"	0.487"	1:48	3/4"	1/2"-20	Rockwell B85	46,500	1	92281A521	0000
	6"	0.466"	1:48	3/4"	1/2"-20	Rockwell B85	46,500	1	92281A522	0000


	18-8 Stainless Steel







					9 Taper Pin—0.589" Large End Diameter

					2"	0.549"	1:48	3/4"	1/2"-20	Rockwell B90	54,000	1	92284A515	00000


					2 1/2"	0.539"	1:48	3/4"	1/2"-20	Rockwell B90	54,000	1	92284A516	00000
					3"	0.529"	1:48	3/4"	1/2"-20	Rockwell B90	54,000	1	92284A517	00000
					3 1/2"	0.518"	1:48	3/4"	1/2"-20	Rockwell B90	54,000	1	92284A518	00000
					4"	0.508"	1:48	3/4"	1/2"-20	Rockwell B90	54,000	1	92284A519	00000
					4 1/2"	0.497"	1:48	3/4"	1/2"-20	Rockwell B90	54,000	1	92284A520	00000
					5"	0.487"	1:48	3/4"	1/2"-20	Rockwell B90	54,000	1	92284A521	00000
					6"	0.466"	1:48	3/4"	1/2"-20	Rockwell B90	54,000	1	92284A522	00000

T-Bolts

Steel

Zinc-Plated Steel

Also known as tank-strap bolts, these T-bolts are commonly used with a band clamp or a strap to hold fuel tanks and other objects in place. The large T-shaped head provides a secure grip for steady tightening.

Steel—Steel T-bolts without a finish are ready to be painted or finished.

Zinc-Plated Steel—Zinc-plated steel T-bolts resist corrosion in wet environments.

Fine Thread—Fine threads are closely spaced to prevent loosening from vibration.

Length—Length is measured from the top of the head.

Thread Spacing—Match the thread spacing of mating components.

					Head
	Thread Size	Lg.	Threading	Thread Spacing	Wd.	Thk.	Tensile Strength, psi		Each
Steel



		1/2"-20	3 3/4"	Partially Threaded	Fine	2"	1/2"	120,000	91285A124	000000


		Zinc-Plated Steel



				1/2"-20	3 3/4"	Partially Threaded	Fine	2"	1/2"	120,000	91285A116	00000

Threaded Locating Pins


Round Head	Diamond Head

Screw the shank into a threaded hole for quick installation and removal. Mate these pins with holes in workpieces for precise alignment.

Diamond Head—Diamond-head pins make less contact with the inside of a hole than round-head pins to reduce sticking and jamming.

	Head		Thread						Round Head		Diamond Head
	Dia. (A)	Ht. (B)	Size	Lg.	Shoulder Ht.	Overall Ht.	Head Dia. Tolerance	Hardness		Each		Each
Steel



		1/2"	11/16"	1/2"-20	11/16"	5/32"	2 1/8"	-0.0015" to -0.001"	Rockwell C60 to Rockwell C64	1529N17	000000	1529N27	000000


		9/16"	11/16"	1/2"-20	21/32"	5/32"	2 1/8"	-0.0015" to -0.001"	Rockwell C60 to Rockwell C64	1529N41	00000	1529N44	00000

Threaded Locating and Support Buttons

Flat Head

Use these buttons to support and position workpieces and fixtures from the bottom or side. Threading makes these buttons easier to replace than press-fit, so they are a good choice for high-wear applications. They’re also known as rest buttons.

Hex—Their hex shape lets you screw them into a threaded hole with a wrench or socket.

			Thread
	Lg.	Wd.	Size	Lg.	Lg. Tolerance	Shape		Each
Steel with Flat Head



		1/2"	5/8"	1/2"-20	1/2"	0.005" to 0.015"	Hex	8479A7	00000


		1/2"	3/4"	1/2"-20	9/16"	0" to 0.015"	Hex	8479A68	0000
		3/4"	5/8"	1/2"-20	1/2"	0.005" to 0.015"	Hex	8479A8	0000
		1"	5/8"	1/2"-20	1/2"	0.005" to 0.015"	Hex	8479A9	0000

Ball-Nose Spring Plungers

Align, position, and lock moving parts for most machining and assembly tasks. These spring plungers have a spring-loaded ball that compresses when a part presses against it, and then pops out into a notch or groove to hold the part in place. Unlike long-nose spring plungers, the ball rolls easily in and out of position, so they're a great fit for applications that require consistent, smooth movement, such as positioning parts in an assembly line and aligning fixtures and jigs when cutting or drilling.

Spring plungers are available with or without a threadlocker. Those with a threadlocker won't wiggle loose from vibration. Spring plungers without a threadlocker are easier to remove.

440C Stainless Steel Nose—The strongest, most wear-resistant stainless steel noses, these grind against hard metal surfaces without denting or scratching. However, they are not as corrosion resistant as 316 stainless steel.

		Nose		Nose Force, lbf		Body		Drive Style
	Thread Size	Extended Lg.	Dia.	Extended	Compressed	Material	Lg.	Front	Back		Each
440C Stainless Steel Nose



		1/2"-20	0.072"	0.281"	6	30	18-8 Stainless Steel	0.75"	Spring Plunger Driver	Slotted	3408A661	000000


		1/2"-20	0.072"	0.281"	6	30	Steel	0.75"	Spring Plunger Driver	Slotted	3408A561	0000

Go/No-Go Threaded Plug Gauges with Handle

Speed up thread tolerance checks—the handle on these gauges gives you a good grip to quickly thread and unthread go or no-go gauges. Use these gauges to make sure nuts, tapped holes, and other parts fall within tolerance. All are precisely manufactured to confirm thread fit. If the plug gauges wear down, you can insert new ones (not included) onto the taperlock handle.

A part is within tolerance if it’s easy to thread the go gauge into the part but difficult to thread the no-go gauge more than two turns.

Go/no-go gauges have both a go gauge on one end of the handle and a no-go gauge on the other to speed up tests. Go gauges check the minimum internal thread size. No-go gauges check the maximum internal thread size.

Class X Gauge

Double-Ended Taperlock

Handle

Calibration Certificate Traceable to NIST—Gauges with a calibration certificate traceable to NIST were calibrated in a lab. The certificate, sometimes called a test report or long-form certificate, details the tested measurements.

For Class 2B Unified Standard Thread Fit—For inch threads, the higher the class number, the tighter the fit. Unified Standard Class 2B is standard and works for most applications.

For Class 3B Unified Standard Thread Fit—The tightest fit for inch-sized threads. Unified Standard Class 3B fits completely flush in applications where parts need to stay in place, such as engines and suspension systems.

For Thread Fit—Thread fit designates the tightness or looseness of mating threads.

	Thread Type	Pitch Dia. Tolerance	Hardness	Material	Features	Choose a Thread Fit		Each
Go/No-Go Gauges



	1/2"-20	UNF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B, Unified Standard Class 3B	2366A532	0000000


	Go/No-Go Gauges with Calibration Certificate Traceable to NIST



			1/2"-20	UNF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B, Unified Standard Class 3B	3157A39	000000

Threaded Plug Gauges

Test if internal threads fall within tolerance. These plug gauges are often used in nuts and tapped holes to confirm thread fit. For precision and accuracy, they’re manufactured to tight tolerances.

Threads are within tolerance if it’s easy to thread a go gauge but difficult to thread a no-go gauge more than two turns.

Class X Gauge

Go Gauge—Go gauges check the minimum hole diameter.

No-Go Gauge—No-go gauges check the maximum hole diameter.

Accuracy Certificate Traceable to NIST—Gauges with an accuracy certificate traceable to NIST include verification from the manufacturer that their thread sizes are within tolerance. The certificate is also known as a certificate of compliance or a short-form certification.

For Class 2B Unified Standard Thread Fit—For inch threads, the higher the class number, the tighter the fit. Unified Standard Class 2B is standard and works for most applications.

For Thread Fit—Thread fit designates the tightness or looseness of mating threads.

	Thread Type	Pitch Dia. Tolerance	Hardness	Material	For Thread Fit		Each
Go Gauges



	1/2"-20	UNF	0" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Unified Standard Class 2B, Unified Standard Class 3B	7968N27	000000


	Go Gauges with Accuracy Certificate Traceable to NIST



			1/2"-20	UNF	0" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Unified Standard Class 2B, Unified Standard Class 3B	7968N117	00000


			No-Go Gauges



					1/2"-20	UNF	-0.0003" to 0"	Rockwell C70	Chrome-Plated Tool Steel	Unified Standard Class 2B	7968N67	00000


					1/2"-20	UNF	-0.0003" to 0"	Rockwell C70	Chrome-Plated Tool Steel	Unified Standard Class 3B	7968N68	00000


					No-Go Gauges with Accuracy Certificate Traceable to NIST



							1/2"-20	UNF	-0.0003" to 0"	Rockwell C70	Chrome-Plated Tool Steel	Unified Standard Class 2B	7968N157	00000


							1/2"-20	UNF	-0.0003" to 0"	Rockwell C70	Chrome-Plated Tool Steel	Unified Standard Class 3B	7968N158	00000

Go/No-Go Left-Hand Threaded Plug Gauges with Handle

A go and no-go gauge in one, these gauges check that left-hand threads fall within tolerance. Use them to confirm thread fit for nuts, tapped holes, and other parts. The taperlock handle speeds up tests, giving you a good grip to thread and unthread each gauge end. It also lets you swap out worn gauges for new ones (not included) on either end.

The go gauge checks the minimum internal thread size, and the no-go gauge checks the maximum. A part is within tolerance if it’s easy to thread the go gauge but difficult to thread the no-go gauge more than two turns.

Class X Gauge

Plug Gauges with Accuracy Certificate Traceable to NIST—Gauges with an accuracy certificate traceable to NIST include verification from the manufacturer that their thread sizes are within tolerance. The certificate is also known as a certificate of compliance or a short-form certification.

Plug Gauges with Calibration Certificate Traceable to NIST—Gauges with a calibration certificate traceable to NIST were calibrated in a lab. The certificate, sometimes called a test report or long-form certificate, details the tested measurements.

For Class 2B Unified Standard Thread Fit—For inch threads, the higher the class number, the tighter the fit. Unified Standard Class 2B is standard and works for most applications.

For Thread Fit—Thread fit designates the tightness or looseness of mating threads.

	Thread Type	Pitch Dia. Tolerance	Hardness	Material	Features	Choose a Thread Fit		Each
Plug Gauges with Accuracy Certificate Traceable to NIST



	1/2"-20	UNF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B, Unified Standard Class 3B	7935N106	0000000


	Plug Gauges with Calibration Certificate Traceable to NIST



			1/2"-20	UNF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B, Unified Standard Class 3B	7938N106	000000

Go/No-Go Helical Insert Threaded Plug Gauges with Handle

Check that holes tapped for helical threads are within tolerance. You’ll sometimes hear these threads referred to as Screw Thread Insert (STI) threads. To speed up tests, these gauges have a go gauge on one end and a no-go gauge on the other. The double-ended taperlock handle makes them quick to thread and unthread. It also lets you swap in new plug gauges (not included) in place of worn ones.

								Plug Gauges with Accuracy Certificate Traceable to NIST		Plug Gauges with Calibration Certificate Traceable to NIST
	Thread Size	Thread Type	Pitch Dia. Tolerance	Hardness	Material	Features	For Thread Fit		Each		Each
Class X Gauge



		1/2"-20	UNF	-0.0003" to 0.0003"	Rockwell C70	Chrome-Plated Tool Steel	Double-Ended Taperlock Handle	Unified Standard Class 2B	7941N25	0000000	7941N43	0000000