4-40 Knobs | McMaster-Carr

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74 Products

Comfort-Grip Indicating Knobs

Style 1—Ribbed

Grip

Style 2—Ribbed

Grip

Style

3—Ribbed

Grip

A rubber coating or construction provides a comfortable grip. Use these knobs to control devices with round or D-shaped shafts and view settings at a glance with a pointer. All resist oil, grease, and solvents.

For Round Shafts—Knobs for round shafts include a set screw to secure them in place.

	Head		Hole					Each
	Dia.	Ht.	Dia.	Dp.	Set Screw Included	Temp. Range, ° F		1-9	10-Up
Style 1—Ribbed Grip







				Black Rubber-Coated Polypropylene—For Round Shafts

				5/8"	9/16"	1/4"	1/2"	Yes	-15 to 210	00000000	00000	00000


				3/4"	11/16"	1/4"	5/8"	Yes	-15 to 210	00000000	0000	0000


				Style 2—Ribbed Grip







								Black Rubber-Coated Polypropylene—For Round Shafts

								1/2"	11/16"	1/8"	5/8"	Yes	-15 to 210	00000000	0000	0000


								Style 3—Ribbed Grip







												Black Rubber-Coated Polypropylene—For Round Shafts

												5/8"	13/16"	1/8"	3/4"	Yes	-15 to 210	00000000	0000	0000

Stainless Steel Raised-Profile Knurled-Head Thumb Screws

The raised head gives your fingers extra space to grab these corrosion-resistant thumb screws, even with oily fingers. The knurled texture creates extra grip as you twist. Install these thumb screws on panels and covers for routinely serviced equipment, such as HVAC access doors and machine safety shields.

Length is measured from under the collar.

18-8 Stainless Steel—The choice for wet and outdoor environments, these screws resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

		Head		Collar
	Lg.	Dia.	Ht.	Dia.	Ht.	Threading	Tensile Strength, psi		Each
18-8 Stainless Steel







				4-40

				1/4"	3/8"	3/32"	1/4"	1/8"	Fully Threaded	80,000	000000000	00000


				3/8"	3/8"	3/32"	1/4"	1/8"	Fully Threaded	80,000	000000000	0000
				7/16"	3/8"	3/32"	1/4"	1/8"	Fully Threaded	80,000	000000000	0000
				1/2"	3/8"	3/32"	1/4"	1/8"	Fully Threaded	80,000	000000000	0000

Plastic-Knurled-Head Thumb Screws

Combine the strength of stainless steel with a lightweight head that won't rust. These thumb screws are an economical alternative to fully metal thumb screws. The knurled texture of the head creates extra grip as you twist.

Length is measured from under the head.

18-8 Stainless Steel with Acetal Head—With a stainless steel body and an acetal head, these screws resist moisture and are chemical resistant.

		Head
	Lg.	Dia.	Ht.	Temp. Range, ° F	Threading	Tensile Strength	Choose a Head Color	Pkg. Qty.		Pkg.
18-8 Stainless Steel with Acetal Head







				4-40

				1/4"	5/16"	11/64"	32 to 180	Fully Threaded	Not Rated	Black , Red	25	000000000	00000


				3/8"	5/16"	11/64"	32 to 180	Fully Threaded	Not Rated	Black , Red	25	000000000	0000
				1/2"	5/16"	11/64"	32 to 180	Fully Threaded	Not Rated	Black , Red	25	000000000	00000
				5/8"	5/16"	11/64"	32 to 180	Fully Threaded	Not Rated	Black , Red	25	000000000	00000
				3/4"	5/16"	11/64"	32 to 180	Fully Threaded	Not Rated	Black , Red	25	000000000	00000
				1"	5/16"	11/64"	32 to 180	Partially Threaded	Not Rated	Black , Red	25	000000000	00000

Stainless Steel Flared-Collar Knurled-Head Thumb Screws

A flared collar leaves more space for your fingers to grasp these corrosion-resistant thumb screws. It also serves as a decorative finish. The knurled texture on the head creates extra grip as you twist.

Length is measured from under the collar.

18-8 Stainless Steel—The choice for wet and outdoor environments, these screws resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

		Head		Collar
	Lg.	Dia.	Ht.	Dia.	Ht.	Threading	Tensile Strength, psi	Pkg. Qty.		Pkg.
18-8 Stainless Steel







				4-40

				1/4"	19/64"	1/8"	15/64"	1/8"	Fully Threaded	80,000	5	000000000	000000


				5/16"	19/64"	1/8"	15/64"	1/8"	Fully Threaded	80,000	5	000000000	00000
				3/8"	19/64"	1/8"	15/64"	1/8"	Fully Threaded	80,000	5	000000000	00000
				7/16"	19/64"	1/8"	15/64"	1/8"	Fully Threaded	80,000	5	000000000	00000
				1/2"	19/64"	1/8"	15/64"	1/8"	Fully Threaded	80,000	5	000000000	00000
				5/8"	19/64"	1/8"	15/64"	1/8"	Fully Threaded	80,000	5	000000000	00000
				3/4"	19/64"	1/8"	15/64"	1/8"	Fully Threaded	80,000	1	000000000	0000
				1"	19/64"	1/8"	15/64"	1/8"	Fully Threaded	80,000	1	000000000	0000

Stainless Steel Narrow-Profile Knurled-Head Thumb Screws

The slim head on these corrosion-resistant thumb screws won't snag plugs and cords in electrical panels and other tight spaces. The narrow width can make them harder to turn than screws with wider heads. However, the knurled texture gives your fingers extra grip.

Length is measured from under the head.

18-8 Stainless Steel—The choice for wet and outdoor environments, these screws resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

		Head
	Lg.	Dia.	Ht.	Threading	Tensile Strength, psi		Each
18-8 Stainless Steel







				4-40

				3/8"	1/4"	1/8"	Fully Threaded	80,000	000000000	00000


				1/2"	1/4"	1/2"	Partially Threaded	80,000	000000000	0000
				5/8"	3/16"	3/8"	Fully Threaded	80,000	000000000	0000
				3/4"	1/4"	1/2"	Partially Threaded	80,000	000000000	0000
				1"	3/16"	3/8"	Fully Threaded	80,000	000000000	0000
				1"	1/4"	1/2"	Fully Threaded	80,000	000000000	0000

Turn-Counting Indicating Knobs


Style 1—Ribbed Grip	Style 2—Ribbed Grip	Style 3—Ribbed Grip

For monitoring the number of shaft turns on instrumentation, these knobs have easy-to-read scales or digits for quick and accurate readings. Use them on devices with round shafts. To secure these knobs in place, tighten the set screw.

Plastic—Plastic knobs are a lightweight alternative to metal. They resist oil, grease, and solvents.

Aluminum—Aluminum knobs have mild corrosion resistance, are lightweight, and are nonmagnetic.

	Head			Housing			Hole
	Dia.	Ht.	Max. Knob Turns	Wd.	Material	Ht.	Dia.	Dp.	Set Screw Included	Temp. Range, ° F		Each
Style 1—Ribbed Grip







				Black Aluminum—For Round Shafts

				1"	1"	10	—	—	—	1/4"	13/16"	Yes	35 to 400	0000000	000000


				Style 2—Ribbed Grip







								Black Plastic—For Round Shafts

								1 1/16"	1 1/4"	10	—	—	—	1/4"	11/16"	Yes	-20 to 185	0000000	000000


								Style 3—Ribbed Grip







												Black Plastic—For Round Shafts

												9/16"	1"	10	1"	Aluminum	1 3/4"	1/4"	1"	Yes	-20 to 185	0000000	000000

Hex-Drive Plastic-Head Thumb Screws

Twist these thumb screws with a hex key when you need more torque than fingers can provide. You can also use a hex key to unfasten them in cramped spaces such as small control boxes. When fastening these thumb screws by hand, the knurled texture of the head creates extra grip as you twist. These thumb screws combine the strength of stainless steel with a lightweight plastic head that won't rust.

Length is measured from under the head.

18-8 Stainless Steel with Acetal Head—With a stainless steel body and an acetal head, these screws resist moisture and are chemical resistant.

		Head
	Lg.	Dia.	Ht.	Temp. Range, ° F	Color	Threading	Tensile Strength	Pkg. Qty.		Pkg.
18-8 Stainless Steel with Acetal Head







				4-40

				9/32"	5/16"	11/64"	32 to 180	Black	Fully Threaded	Not Rated	25	000000000	000000


				13/32"	5/16"	11/64"	32 to 180	Black	Fully Threaded	Not Rated	25	000000000	00000
				17/32"	5/16"	11/64"	32 to 180	Black	Fully Threaded	Not Rated	25	000000000	00000
				21/32"	5/16"	11/64"	32 to 180	Black	Fully Threaded	Not Rated	10	000000000	0000
				25/32"	5/16"	11/64"	32 to 180	Black	Fully Threaded	Not Rated	10	000000000	0000
				29/32"	5/16"	11/64"	32 to 180	Black	Partially Threaded	Not Rated	10	000000000	0000

Steel Raised-Profile Knurled-Head Thumb Screws

The raised head gives your fingers extra space to grab these thumb screws, even with oily fingers. The knurled texture creates extra grip as you twist. Install these thumb screws on panels and covers for routinely serviced equipment, such as HVAC access doors and machine safety shields.

Length is measured from under the collar.

Black-Oxide Steel—Typically chosen for their appearance, these screws have a dark, matte coating to create a finished look. They offer minimal corrosion resistance, so they're best for dry environments.

		Head		Collar
	Lg.	Dia.	Ht.	Dia.	Ht.	Threading	Tensile Strength, psi		Each
Black-Oxide Steel







				4-40

				1/4"	3/8"	3/32"	1/4"	3/32"	Fully Threaded	70,000	000000000	00000


				3/8"	3/8"	3/32"	1/4"	3/32"	Fully Threaded	70,000	000000000	0000
				7/16"	3/8"	3/32"	1/4"	3/32"	Fully Threaded	70,000	000000000	0000

Slotted Plastic High-Profile Knurled-Head Thumb Screws

Twist these nonconductive, rust-resistant, lightweight thumb screws by driver and by hand. The head is nearly twice as tall as low-profile heads for a better grasp. In cramped spaces where fingers can't fit, such as small control boxes, turn these screws with a slotted driver. When twisting by hand, the knurled texture of the screw head creates extra grip.

Length is measured from under the head.

Nylon—These screws are slippery and abrasion resistant, so they thread in smoothly and stand up to daily wear and tear.

		Head
	Lg.	Dia.	Ht.	Threading	Tensile Strength, psi	Temp. Range, ° F	Choose a Color	Pkg. Qty.		Pkg.
Nylon







				4-40

				1/4"	21/64"	7/32"	Fully Threaded	11,000	-40 to 185	Black , Off-White	100	000000000	000000

Aluminum Flared-Collar Knurled-Head Thumb Screws

Our most lightweight flared-collar thumb screws, these are one-third the weight of steel. The flared collar leaves more space for your fingers to grasp the head, and adds a decorative look. The knurled texture creates extra grip as you twist.

Length is measured from under the collar.

		Head		Collar
	Lg.	Dia.	Ht.	Dia.	Ht.	Threading	Tensile Strength, psi	Material	Pkg. Qty.		Pkg.
4-40



		5/16"	3/8"	3/16"	3/8"	1/8"	Fully Threaded	40,000	6061 Aluminum	1	000000000	00000


		3/8"	3/8"	3/16"	3/8"	1/8"	Fully Threaded	40,000	6061 Aluminum	1	000000000	0000
		7/16"	3/8"	3/16"	3/8"	1/8"	Fully Threaded	40,000	6061 Aluminum	1	000000000	0000

Threaded-Hole-Mount Pull Handles

Style 1

Thread screws through holes from the back of your surface into the handles to open and close a variety of doors and drawers, including those on furniture, machines, and equipment.

Round Grip—Round grips allow your hand to pivot in any direction.

303 Stainless Steel—Stainless steel handles have excellent corrosion resistance, making them the best choice for harsh environments. They also have good chemical resistance.

Anodized Aluminum—Aluminum handles have mild corrosion resistance, are lightweight, and are nonmagnetic.

	Mounting Hole		Thread
	No. of	Ctr.-to-Ctr. Wd.	Size	Dp.	Grip Dia.	Projection	Pull Cap.	Mounting Screw Lg.	Mounting Fasteners Included		Each
Style 1—Round Grip







				303 Stainless Steel—Dull

				2	2"	4-40	1/4"	3/16"	1"	Not Rated	1/4"	Yes	0000000	00000


				2	3"	4-40	1/4"	3/16"	1"	Not Rated	3/8"	Yes	0000000	0000




						Anodized Aluminum—Dull

						2	1 1/4"	4-40	1/4"	3/16"	1"	Not Rated	1/4"	Yes	0000000	0000


						2	2"	4-40	1/4"	3/16"	1"	Not Rated	1/4"	Yes	0000000	0000




								Black Anodized Aluminum—Dull

								2	1 1/4"	4-40	1/4"	3/16"	1"	Not Rated	1/4"	Yes	0000000	0000


								2	2"	4-40	1/4"	3/16"	1"	Not Rated	1/4"	Yes	0000000	0000

Dual-Control Comfort-Grip Indicating Knobs

These dual-control knobs operate independently to control two settings. They have a rubber coating for a comfortable grip. Use them on devices with round shafts to view settings at a glance with a pointer. To secure these knobs in place, tighten the set screw. Made of polypropylene, all resist oil, grease, and solvents.

For Round Shafts—Knobs for round shafts include a set screw to secure them in place.

	Head		Hole					Each
	Dia.	Ht.	Dia.	Dp.	Set Screw Included	Temp. Range, ° F		1-9	10-Up
Ribbed Grip







				Black Rubber-Coated Polypropylene—For Round Shafts

				5/8"	1 1/8"	1/8", 1/4"	1"	Yes	-15 to 200	0000000	000000	00000

Quick-Release Shaft Collar Adjustable Handles

These threaded handles take the place of a set screw, allowing you to move set screw shaft collars without additional tools—useful for when the collar serves as a stroke limiter or mounting clamp. The handle keeps your collar secure on the shaft, then lets you loosen and tighten the collar for quick adjustments.

Black-Oxide 1215 Carbon Steel—Black-oxide 1215 carbon steel handles have some corrosion resistance.

303 Stainless Steel—303 stainless steel handles have excellent corrosion resistance.

Thread					Black-Oxide 1215 Carbon Steel		303 Stainless Steel
Size	Lg.	Overall Lg.	Handle Dia.	Handle Texture		Each		Each
4-40	3/8"	3 3/8"	1/2"	Knurled	0000000	000000	0000000	000000

Brass Raised-Profile Knurled-Head Thumb Screws

Fasten plates and covers in server racks and electrical enclosures that need frequent access. Conductive and nonmagnetic, these thumb screws have a shiny, rust-resistant finish. The raised head gives your fingers extra space to grab these thumb screws, even with oily fingers. The knurled texture creates extra grip as you twist.

Length is measured from under the collar.

		Head		Collar
	Lg.	Dia.	Ht.	Dia.	Ht.	Threading	Tensile Strength, psi		Each
Brass







				4-40

				1/4"	3/8"	3/32"	1/4"	3/32"	Fully Threaded	50,000	000000000	00000


				3/8"	3/8"	3/32"	1/4"	3/32"	Fully Threaded	50,000	000000000	0000

Stainless Steel Knurled-Head Thumb Screws

Fasten panels and covers exposed to moisture and chemicals with these corrosion-resistant thumb screws. The knurled texture of the head creates extra grip as you twist.

Length is measured from under the head.

18-8 Stainless Steel—The choice for wet and outdoor environments, these screws resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

		Head
	Lg.	Dia.	Ht.	Threading	Tensile Strength, psi		Each
18-8 Stainless Steel







				4-40

				5/16"	5/16"	3/16"	Fully Threaded	80,000	000000000	00000


				3/8"	5/16"	3/16"	Fully Threaded	80,000	000000000	0000
				3/8"	3/8"	1/8"	Partially Threaded	80,000	000000000	0000
				1/2"	5/16"	3/16"	Fully Threaded	80,000	000000000	0000

Slotted Stainless Steel Knurled-Head Thumb Screws

Fasten these corrosion-resistant thumb screws by driver and by hand. In cramped spaces where fingers can't fit, such as small control boxes, turn these screws with a slotted driver. When twisting by hand, the knurled texture of the screw head creates extra grip.

Length is measured from under the head.

18-8 Stainless Steel—The choice for wet and outdoor environments, these screws resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

		Head
	Lg.	Dia.	Ht.	Threading	Tensile Strength, psi		Each
18-8 Stainless Steel







				4-40

				5/16"	5/16"	3/16"	Fully Threaded	80,000	000000000	00000


				3/8"	5/16"	3/16"	Fully Threaded	80,000	000000000	0000
				3/8"	3/8"	1/8"	Partially Threaded	80,000	000000000	0000
				1/2"	5/16"	3/16"	Fully Threaded	80,000	000000000	0000

Slotted Stainless Steel Narrow-Profile Knurled-Head Thumb Screws

Fasten these slim, corrosion-resistant screws by driver and by hand in even the tightest of spaces. Turn these screws with a slotted driver in cramped spaces where fingers can't fit. When twisting by hand, the knurled texture of the screw head creates extra grip.

Length is measured from under the head.

18-8 Stainless Steel—The choice for wet and outdoor environments, these screws resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

		Head
	Lg.	Dia.	Ht.	Threading	Tensile Strength, psi		Each
18-8 Stainless Steel







				4-40

				3/8"	1/4"	1/8"	Fully Threaded	80,000	000000000	00000


				1/2"	1/4"	1/2"	Partially Threaded	80,000	000000000	0000
				3/4"	1/4"	1/2"	Partially Threaded	80,000	000000000	0000
				1"	3/16"	3/8"	Fully Threaded	80,000	000000000	0000
				1"	1/4"	1/2"	Fully Threaded	80,000	000000000	0000

Miniature Threaded-Hole-Mount Pull Handles

With a mounting hole center-to-center distance of 1" or less, these are the smallest pull handles we offer. Thread screws through holes from the back of your surface into the handles to open and close tiny doors and drawers. All have a round grip that allows your fingers to pivot in any direction.

Anodized Aluminum—Aluminum handles have mild corrosion resistance, are lightweight, and are nonmagnetic.

	Mounting Hole		Thread
	No. of	Ctr.-to-Ctr. Wd.	Size	Dp.	Grip Dia.	Projection	Pull Cap.	Mounting Screw Lg.	Mounting Fasteners Included		Each
Round Grip







				Anodized Aluminum—Dull

				2	1"	4-40	1/4"	3/16"	1"	Not Rated	1/4"	Yes	0000000	00000




						Black Anodized Aluminum—Dull

						2	1"	4-40	1/4"	3/16"	1"	Not Rated	1/4"	Yes	0000000	0000

Brass Knurled-Head Thumb Screws

Fasten plates and covers on electrical equipment with these thumb screws. They're conductive and nonmagnetic, with a shiny, rust-resistant finish. The knurled texture on the head creates extra grip as you twist.

Length is measured from under the head.

		Head
	Lg.	Dia.	Ht.	Threading	Tensile Strength, psi		Each
Brass







				4-40

				5/16"	5/16"	3/16"	Fully Threaded	50,000	000000000	00000


				3/8"	5/16"	3/16"	Fully Threaded	50,000	000000000	0000

Stainless Steel Hex-Head Thumb Screws

When you need more torque than fingers alone can provide, crank these stainless steel thumb screws with a wrench. For finger tightening, the thick, hex-shaped head transmits added torque for a stronger hold than other head shapes. These thumb screws aren't recommended for structural, load-bearing applications.

Length is measured from under the head.

18-8 Stainless Steel—The choice for wet and outdoor environments, these screws resist rust. However, they won't hold up to the harsh chemicals that 316 stainless steel can.

		Head
	Lg.	Wd.	Ht.	Threading	Tensile Strength, psi		Each
18-8 Stainless Steel







				4-40

				1/2"	3/8"	1/4"	Fully Threaded	80,000	000000000	00000

Steel Hex-Head Thumb Screws

When you need more torque than fingers alone can provide, crank these thumb screws with a wrench. For finger tightening, the thick, hex-shaped head transmits added torque for a stronger hold than other head shapes. These thumb screws aren't recommended for structural, load-bearing applications.

Length is measured from under the head.

		Head
	Lg.	Wd.	Ht.	Threading	Tensile Strength, psi		Each
Black-Oxide Steel







				4-40

				1/2"	3/8"	1/4"	Fully Threaded	70,000	000000000	00000