3/4"-8 Rods | McMaster-Carr

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52 Products

Acme Lead Screws and Nuts

Found in hand-powered clamps, vises, grates, doors, and work tables, lead screws and nuts have broad, square threads that are well suited for quick assembly, high clamping forces, and lifting and lowering heavy objects. To ensure compatibility, please select components that have the same thread direction, thread size, and number of thread starts.

Lead Screws—Right-Hand Thread

Carbon Steel—Carbon steel components are easier to machine than alloy steel components.

Alloy Steel—Alloy steel components are harder and stronger than carbon steel components.

18-8 Stainless Steel—18-8 stainless steel components have good corrosion resistance.

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

	Thread Type	Lg.	No. of Thread Starts	Speed Ratio	Travel Distance per Turn	Thread Fit	Fastener Strength Grade/Class	Hardness	Tensile Strength, psi	Specs. Met		Each
Carbon Steel



	3/4"-8	Acme	12"	1	1:1	0.125"	Acme Class 2G	SAE Grade 2	Rockwell B61	64,000	ASTM A108	98935A736	00000


	3/4"-8	Acme	3 ft.	1	1:1	0.125"	Acme Class 2G	SAE Grade 2	Rockwell B61	64,000	ASTM A108	98935A842	00000
	3/4"-8	Acme	6 ft.	1	1:1	0.125"	Acme Class 2G	SAE Grade 2	Rockwell B61	64,000	ASTM A108	98935A039	00000


	Alloy Steel



			3/4"-8	Acme	12"	1	1:1	0.125"	Acme Class 2G	ASTM Grade B7	Rockwell C35	125,000	ASTM A193	93410A944	00000


			3/4"-8	Acme	3 ft.	1	1:1	0.125"	Acme Class 2G	ASTM Grade B7	Rockwell C35	125,000	ASTM A193	93410A628	00000
			3/4"-8	Acme	6 ft.	1	1:1	0.125"	Acme Class 2G	ASTM Grade B7	Rockwell C35	125,000	ASTM A193	93410A330	000000


			18-8 Stainless Steel



					3/4"-8	Acme	12"	1	1:1	0.125"	Acme Class 2G	—	Rockwell B96	Not Rated	—	95061A630	00000


					3/4"-8	Acme	3 ft.	1	1:1	0.125"	Acme Class 2G	—	Rockwell B96	Not Rated	—	95061A835	000000
					3/4"-8	Acme	6 ft.	1	1:1	0.125"	Acme Class 2G	—	Rockwell B96	Not Rated	—	95061A533	000000

Lead Screws—Left-Hand Thread

Carbon Steel—Carbon steel components are easier to machine than alloy steel components.

Alloy Steel—Alloy steel components are harder and stronger than carbon steel components.

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

	Thread Type	Lg., ft.	No. of Thread Starts	Speed Ratio	Travel Distance per Turn	Thread Fit	Fastener Strength Grade/Class	Hardness	Tensile Strength, psi	Specs. Met		Each
Carbon Steel



	3/4"-8	Acme	3	1	1:1	0.125"	Acme Class 2G	SAE Grade 2	Rockwell B61	64,000	ASTM A108	98935A451	000000


	3/4"-8	Acme	6	1	1:1	0.125"	Acme Class 2G	SAE Grade 2	Rockwell B61	64,000	ASTM A108	98935A452	00000


	Alloy Steel



			3/4"-8	Acme	3	1	1:1	0.125"	Acme Class 2G	ASTM Grade B7	Rockwell C35	125,000	ASTM A193	93410A449	00000


			3/4"-8	Acme	6	1	1:1	0.125"	Acme Class 2G	ASTM Grade B7	Rockwell C35	125,000	ASTM A193	93410A450	000000

Hex Nuts—Right-Hand Thread

Hex nuts fasten and position lead screw components.

Carbon Steel—Carbon steel components are easier to machine than alloy steel components.

Zinc-Plated Carbon Steel—Zinc-plated carbon steel components have mild corrosion resistance and are easier to machine than alloy steel components.

18-8 Stainless Steel—18-8 stainless steel components have good corrosion resistance.

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

	Thread Type	Ht.	Wd.	No. of Thread Starts	Speed Ratio	Travel Distance per Turn	Thread Fit	Hardness	Tensile Strength		Each
Carbon Steel



	3/4"-8	Acme	47/64"	1 1/4"	1	1:1	0.125"	Acme Class 2G	Rockwell B75	Not Rated	94815A034	00000


	Zinc-Plated Carbon Steel



			3/4"-8	Acme	47/64"	1 1/4"	1	1:1	0.125"	Acme Class 2G	Rockwell B75	Not Rated	98948A118	00000


			18-8 Stainless Steel



					3/4"-8	Acme	47/64"	1 1/4"	1	1:1	0.125"	Acme Class 2G	Rockwell B97	Not Rated	95066A152	00000

Hex Nuts—Left-Hand Thread

Hex nuts fasten and position lead screw components.

Carbon Steel—Carbon steel components are easier to machine than alloy steel components.

18-8 Stainless Steel—18-8 stainless steel components have good corrosion resistance.

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

	Thread Type	Ht.	Wd.	No. of Thread Starts	Speed Ratio	Travel Distance per Turn	Thread Fit	Fastener Strength Grade/Class	Hardness	Tensile Strength, psi		Each
Carbon Steel



	3/4"-8	Acme	47/64"	1 1/4"	1	1:1	0.125"	Acme Class 2G	SAE Grade 2	Rockwell B85	64,000	91808A046	00000


	18-8 Stainless Steel



			3/4"-8	Acme	47/64"	1 1/4"	1	1:1	0.125"	Acme Class 2G	—	Rockwell B97	Not Rated	95066A383	00000

Fast-Travel Precision Acme Lead Screws and Nuts

Multiple thread channels (also known as thread starts) create faster linear travel than lead screws with a single thread start. The threads have a tight thread fit for accurate, repeatable starts and stops. Pair with a motor in automated motion and positioning applications. To ensure compatibility, please select components that have the same thread direction, thread size, and number of thread starts.

Lead Screws—Right-Hand Thread

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

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., ft.	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



	3/4"-8	3	Acme	2:1	2	0.25"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A073	000000


	3/4"-8	3	Acme	4:1	4	0.5"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A500	00000
	3/4"-8	6	Acme	2:1	2	0.25"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A173	000000
	3/4"-8	6	Acme	4:1	4	0.5"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A600	00000


	304 Stainless Steel



			3/4"-8	3	Acme	4:1	4	0.5"	±0.009"/1 ft.	Acme Class 2C	Not Rated	Not Rated	98980A983	000000


			3/4"-8	6	Acme	4:1	4	0.5"	±0.009"/1 ft.	Acme Class 2C	Brinell 150	72,000	98980A187	000000

Lead Screws—Left-Hand Thread

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

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	Thread Fit	Hardness	Tensile Strength, psi		Each
1018 Low-Carbon Steel



	3/4"-8	3	Acme	2:1	2	0.25"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A473	000000


	3/4"-8	6	Acme	2:1	2	0.25"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A573	000000

Externally Threaded Nuts—Right-Hand Thread

Image of Product. Front orientation. Contains Annotated. Precision Lead Screws and Nuts. Fast-Travel 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.

673 Bronze—932 bearing bronze and 673 bronze nuts are wear resistant. They have good machinability and fair corrosion resistance.

PET—PET plastic nuts are lightweight and corrosion resistant.

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	Dynamic Thrust Load Cap., lb.	Temp., ° F		Each
360 Brass



		3/4"-8	1 1/4"	1.125"	Acme	2:1	2	0.25"	1"-18	1/2"	Acme Class 2C	Brinell 130	Not Rated	2,800	—	95072A331	000000


		673 Bronze



				3/4"-8	1 1/4"	1.125"	Acme	4:1	4	0.5"	1"-18	1/2"	Acme Class 2C	Brinell 70	Not Rated	Not Rated	—	95072A540	00000


				PET



						3/4"-8	1 1/4"	1.125"	Acme	4:1	4	0.5"	1"-18	1/2"	Acme Class 2C	Not Rated	Not Rated	1,450	15 to 175	95075A230	00000

Externally Threaded Nuts—Left-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.

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	Dynamic Thrust Load Cap., lb.		Each
360 Brass



		3/4"-8	1 1/4"	1.125"	Acme	2:1	2	0.25"	1"-18	1/2"	Acme Class 2C	Brinell 130	Not Rated	2,800	95072A332	000000

Flanges

Image of Attribute. Front orientation. Contains Annotated.

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

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
1215 Carbon Steel



	1"-18	2 5/8"	17/32"	2 3/32"	Not Rated	95082A643	000000


	303 Stainless Steel



			1"-18	2 5/8"	17/32"	2 3/32"	Brinell 140	1329K13	00000

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



	3/4"-8	3 ft.	Acme	1:1	1	0.125"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A075	000000


	3/4"-8	6 ft.	Acme	1:1	1	0.125"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A175	00000


	Black-Oxide 4140 Alloy Steel



			3/4"-8	18"	Acme	1:1	1	0.125"	±0.0003"/1"	Acme Class 2C	Brinell 200	60,000	98940A194	00000


			3/4"-8	3 ft.	Acme	1:1	1	0.125"	±0.0003"/1"	Acme Class 2C	Brinell 200	60,000	98940A195	00000
			3/4"-8	6 ft.	Acme	1:1	1	0.125"	±0.0003"/1"	Acme Class 2C	Brinell 200	60,000	98940A196	000000


			304 Stainless Steel



					3/4"-8	18"	Acme	1:1	1	0.125"	±0.0003"/1"	Acme Class 2C	Brinell 170	31,000	90497A210	00000


					3/4"-8	3 ft.	Acme	1:1	1	0.125"	±0.0003"/1"	Acme Class 2C	Brinell 170	31,000	90497A220	000000
					3/4"-8	6 ft.	Acme	1:1	1	0.125"	±0.0003"/1"	Acme Class 2C	Brinell 170	31,000	90497A230	000000

Lead Screws—Left-Hand Thread


	Left-Hand Threads

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

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	Thread Fit	Hardness	Tensile Strength, psi		Each
1018 Low-Carbon Steel



	3/4"-8	3	Acme	1:1	1	0.125"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A475	000000


	3/4"-8	6	Acme	1:1	1	0.125"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A575	00000

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.

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.

								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



		3/4"-8	1 1/4"	1.125"	Acme	1:1	1	0.125"	1"-18	1/2"	Acme Class 2C	Brinell 70	Not Rated	2,800	—	95072A351	000000


		Acetal



				3/4"-8	1 1/4"	1.125"	Acme	1:1	1	0.125"	1"-18	1/2"	Acme Class 2C	Rockwell R120	8,000	1,400	-40 to 190	90493A110	00000

Externally Threaded Nuts—Left-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.

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	Dynamic Thrust Load Cap., lb.		Each
360 Brass



		3/4"-8	1 1/4"	1.125"	Acme	1:1	1	0.125"	1"-18	1/2"	Acme Class 2C	Brinell 70	Not Rated	2,800	95072A352	000000

Flanges

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

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
1215 Carbon Steel



	1"-18	2 5/8"	17/32"	2 3/32"	Not Rated	95082A643	000000


	303 Stainless Steel



			1"-18	2 5/8"	17/32"	2 3/32"	Brinell 140	1329K13	00000

Fast-Travel Ultra-Precision Lead Screws and Nuts


	Style B

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



	3/4"-8	3	Rounded Acme	2:1	2	0.25"	±0.0006"/1"	Brinell 160	90,000	6350K723	0000000


	3/4"-8	3	Rounded Acme	8:1	8	1"	±0.0006"/1"	Brinell 160	90,000	6350K724	000000
	3/4"-8	6	Rounded Acme	2:1	2	0.25"	±0.0006"/1"	Brinell 160	90,000	6350K25	000000
	3/4"-8	6	Rounded Acme	8:1	8	1"	±0.0006"/1"	Brinell 160	90,000	6350K725	000000

Flange Nuts—Right-Hand Thread


Style B	Style B

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	3/4"-8	2"	1.125"	1 3/4"	1/4"	Rounded Acme	8:1	1 7/16"	8	1"	Not Rated	9,000	350	3	6350K684	000000


		B	3/4"-8	2"	1.125"	1 51/64"	1/4"	Rounded Acme	2:1	1 7/16"	2	0.25"	Not Rated	9,700	350	3	6350K45	00000


		Acetal with Wear-Compensating Spring



				B	3/4"-8	2 45/64"	1.563"	2 13/32"	5/16"	Rounded Acme	2:1	2"	2	0.25"	Not Rated	9,700	150	3	6350K65	000000