1/4"-20 Lead Screws | McMaster-Carr

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System of Measurement

Component

Length

Nut Type

Material

Travel Distance per Turn

Threading

Number of Thread Starts

Diameter

Thread Type

Thread Direction

Speed Ratio

Shaft Diameter

REACH

RoHS

Hardness

Tensile Strength

10,000 psi to 19,999 psi

40,000 psi to 99,999 psi

Not Rated

Export Control Classification Number (ECCN)

EAR99

DFARS Specialty Metals

Exempt

Thread Fit

Acme Class 2C

Finish

Black Oxide

Dynamic Thrust Load Capacity

Less than 1,000 lb.

Performance

Fast Travel

Ultra Precision

Width

Mounting Hole Thread Size

1/4"-20

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26 Products

Precision Acme Lead Screws and Nuts

Pair with a motor in automated motion and positioning applications. A tight thread fit allows these lead screws and nuts to make accurate, repeatable starts and stops. Also known as single-start and self-locking lead screws and nuts, they have a single thread that runs the length of the screw. The nut travels only when the screw turns, so your system won’t unexpectedly move when the lead screw is at rest. To ensure compatibility, please select components that have the same thread direction, thread size, and number of thread starts.

Lead Screws—Right-Hand Thread


	Right-Hand Threads

1018 Low-Carbon Steel—Carbon steel lead screws and flanges have good machinability.

Black-Oxide 4140 Alloy Steel—Black-oxide alloy steel lead screws are hard and strong. They have mild corrosion resistance and a dark surface color.

304 Stainless Steel—304 stainless steel lead screws have good corrosion resistance.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

	Lg.	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn	Accuracy for Travel Distance per Turn	Thread Fit	Hardness	Tensile Strength, psi		Each
1018 Low-Carbon Steel



	1/4"-20	18"	Acme	1:1	1	0.05"	±0.009"/1 ft.	Acme Class 2C	Not Rated	Not Rated	000000000	000000


	1/4"-20	3 ft.	Acme	1:1	1	0.05"	±0.009"/1 ft.	Acme Class 2C	Not Rated	Not Rated	000000000	00000


	Black-Oxide 4140 Alloy Steel



			1/4"-20	18"	Acme	1:1	1	0.05"	±0.0003"/1"	Acme Class 2C	Brinell 200	60,000	000000000	00000


			1/4"-20	3 ft.	Acme	1:1	1	0.05"	±0.0003"/1"	Acme Class 2C	Brinell 200	60,000	000000000	00000
			1/4"-20	6 ft.	Acme	1:1	1	0.05"	±0.0003"/1"	Acme Class 2C	Brinell 200	60,000	000000000	000000


			304 Stainless Steel



					1/4"-20	18"	Acme	1:1	1	0.05"	±0.009"/1 ft.	Acme Class 2C	Not Rated	Not Rated	000000000	00000


					1/4"-20	3 ft.	Acme	1:1	1	0.05"	±0.009"/1 ft.	Acme Class 2C	Not Rated	Not Rated	000000000	00000
					1/4"-20	6 ft.	Acme	1:1	1	0.05"	±0.009"/1 ft.	Acme Class 2C	Brinell 150	72,000	000000000	000000

Externally Threaded Nuts—Right-Hand Thread

Image of Product. Front orientation. Contains Annotated. Precision Lead Screws and Nuts. Precision Acme Lead Screws and Nuts, Externally Threaded Nuts—Right-Hand Thread.

Combine externally threaded nuts with a flange to create a custom flange nut.

360 Brass—360 brass nuts have excellent machinability and good corrosion resistance.

PET—PET plastic nuts are lightweight and corrosion resistant.

PEEK—PEEK plastic nuts handle twice as much heat as PET and acetal plastic nuts. They have good chemical resistance and excellent corrosion resistance.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

								External Thread
	Thread Size	Lg.	Dia.	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn	Size	Lg.	Thread Fit	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	Temp., ° F		Each
360 Brass



		1/4"-20	5/8"	0.688"	Acme	1:1	1	0.05"	9/16"-18	3/8"	Acme Class 2C	Brinell 141	50,000	310	—	000000000	000000


		PET



				1/4"-20	5/8"	0.688"	Acme	1:1	1	0.05"	9/16"-18	3/8"	Acme Class 2C	Not Rated	Not Rated	160	15 to 175	000000000	00000


				PEEK



						1/4"-20	5/8"	0.688"	Acme	1:1	1	0.05"	9/16"-18	3/8"	Acme Class 2C	Not Rated	16,000	150	-40 to 525	000000000	000000

Flanges

Image of Attribute. Front orientation. Contains Annotated.

Thread onto an externally threaded acme nut to create a custom flange nut.

Black-Oxide 1117 Carbon Steel—Black-oxide carbon steel flanges have mild corrosion resistance in dry environments and a dark surface color.

1215 Carbon Steel—Carbon steel flanges have good machinability. However, they will rust when exposed to moisture.

303 Stainless Steel—303 stainless steel flanges have good corrosion resistance.

	Flange Dia.	Flange Thk.	Bolt Circle Dia.	Flange Hardness		Each
Black-Oxide 1117 Carbon Steel



	9/16"-18	1 39/64"	13/32"	1 1/8"	Brinell 135	00000000	000000


	1215 Carbon Steel



			9/16"-18	1 39/64"	13/32"	1 1/8"	Not Rated	000000000	00000


			303 Stainless Steel



					9/16"-18	1 39/64"	13/32"	1 1/8"	Brinell 140	0000000	00000

Ultra-Precision Lead Screws and Nuts


Style B	Style C

Operating with less backlash (play) than Precision Acme Lead Screws and Nuts, these provide increased nut life and more reliable movement in automated systems. Also known as single-start and self-locking lead screws and nuts, they have a single thread that runs the length of the screw. The nut travels only when the screw turns, so your system won’t unexpectedly move when the lead screw is at rest. All components are corrosion resistant for use in harsh environments. To ensure compatibility, select components that have the same thread type, thread size, and number of thread starts.

Lead Screws—Right-Hand Thread

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

	Lg., ft.	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn	Accuracy for Travel Distance per Turn	Hardness	Tensile Strength, psi		Each
303 Stainless Steel



	1/4"-20	1	Rounded Acme	1:1	1	0.05"	±0.0006"/1"	Brinell 160	90,000	00000000	000000


	1/4"-20	3	Rounded Acme	1:1	1	0.05"	±0.0006"/1"	Brinell 160	90,000	00000000	000000
	1/4"-20	6	Rounded Acme	1:1	1	0.05"	±0.0006"/1"	Brinell 160	90,000	00000000	000000

Flange Nuts—Right-Hand Thread


Style B	Style C


Style B	Style C

Acetal—Acetal nuts have good wear and corrosion resistance.

Wear-Compensating Spring—Flange nuts with wear-compensating internal O-ring or wear-compensating spring maintain a tight fit even when their threads begin to wear. They resist backlash to maintain accuracy over time, which is important in positioning applications such as 3D printing and robotics.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

					Flange
	Style	Thread Size	Lg.	Dia.	Dia.	Thk.	Thread Type	Speed Ratio	Bolt Circle Dia.	No. of Thread Starts	Travel Distance per Turn	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	No. of Mounting Holes		Each
Acetal



		B	1/4"-20	1"	0.5"	1"	3/16"	Rounded Acme	1:1	3/4"	1	0.05"	Not Rated	9,700	50	3	00000000	000000


		Acetal with Wear-Compensating Spring



				C	1/4"-20	1"	0.5"	1"	3/16"	Rounded Acme	1:1	3/4"	1	0.05"	Not Rated	9,700	5	3	00000000	00000

Threadless Lead Screw Nuts

Shown with Rotary Shaft (Not

Included)

Install these nuts on a rotary shaft to create a linear positioning system without a lead screw. Instead of threads, a set of angled ball bearings drives the nut along a shaft as it spins. Nuts move towards you when the shaft rotates clockwise and away from you when the shaft rotates counterclockwise. To prevent overload damage, these nuts can be adjusted to slip and stop travelling at a given thrust load. Thrust loads are loads that are applied parallel to the shaft. Bearings are permanently lubricated to save maintenance time and effort.

Threadless Nuts

Image of Attribute. Front orientation. Contains Annotated. Threadless Lead Screw Nuts.

Travel Distance per Turn—Travel distance per turn is the distance the nut moves with one revolution of the shaft.

					Overall			Mounting Hole
	Ctr. Ht.	For Shaft Dia.	Travel Distance per Turn	Max. Thrust Cap. Before Slip, lb.	Lg.	Wd.	Ht.	Ctr.-to-Ctr. Lg.	Thread Size	No. of	Construction	Temp., ° F		Each
Aluminum with Thrust Adjustment Bolts



		1 1/64"	1/2"	0.2"	60	3 27/64"	2"	2 11/16"	1 1/4"	1/4"-20	2	Two Piece	-10 to 180	0000000	0000000


		1 1/64"	1/2"	0.5"	60	3 27/64"	2"	2 11/16"	1 1/4"	1/4"-20	2	Two Piece	-10 to 180	0000000	000000
		1 1/64"	3/4"	0.75"	60	3 27/64"	2"	2 11/16"	1 1/4"	1/4"-20	2	Two Piece	-10 to 180	0000000	000000

Fast-Travel Ultra-Precision Lead Screws and Nuts


	Style B	Style C

Multiple thread channels (also known as thread starts) create faster linear travel than lead screws with a single thread start. Operating with less backlash (play) than Precision Acme Lead Screws and Nuts, these lead screws and nuts provide increased nut life and more reliable movement in automated systems. All components are corrosion resistant for use in harsh environments. To ensure compatibility, select components that have the same thread type, thread size, and number of thread starts.

Lead Screws—Right-Hand Thread

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

	Lg., ft.	Thread Type	Speed Ratio	No. of Thread Starts	Travel Distance per Turn	Accuracy for Travel Distance per Turn	Hardness	Tensile Strength, psi		Each
303 Stainless Steel



	1/4"-20	3	Rounded Acme	2:1	2	0.1"	±0.0006"/1"	Brinell 160	90,000	00000000	000000


	1/4"-20	6	Rounded Acme	2:1	2	0.1"	±0.0006"/1"	Brinell 160	90,000	00000000	000000

Flange Nuts—Right-Hand Thread


Style B	Style C


Style B	Style C

Acetal—Acetal nuts have good wear and corrosion resistance.

Travel Distance per Turn—Travel distance per turn, also known as screw lead, is the distance a nut moves with one revolution of the lead screw.

					Flange
	Style	Thread Size	Lg.	Dia.	Dia.	Thk.	Thread Type	Speed Ratio	Bolt Circle Dia.	No. of Thread Starts	Travel Distance per Turn	Hardness	Tensile Strength, psi	Dynamic Thrust Load Cap., lb.	No. of Mounting Holes		Each
Acetal



		B	1/4"-20	1"	0.5"	1"	3/16"	Rounded Acme	2:1	3/4"	2	0.1"	Not Rated	9,700	50	3	00000000	000000


		Acetal with Wear-Compensating Spring



				C	1/4"-20	1"	0.5"	1"	3/16"	Rounded Acme	2:1	3/4"	2	0.1"	Not Rated	9,700	5	3	00000000	00000