2 1/2"-4 Screws | McMaster-Carr

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21 Products

Steel Socket Head Screws


Fully Threaded	Partially Threaded

Made of alloy steel, these screws are the standard for high-strength fastening. Use them in high-load applications such as dies, presses, and heavy equipment. The deep, six-point socket keeps the hex key from slipping out and damaging the drive.

Length is measured from under the head.

Black-Oxide Alloy 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
	Lg.	Dia.	Ht.	Threading	Thread Spacing	Tensile Strength, psi	Specs. Met	Pkg. Qty.		Pkg.
Black-Oxide Alloy Steel







				2 1/2"-4

				4"	3 3/4"	2 1/2"	Fully Threaded	Coarse	170,000	ASTM A574	1	90044A231	0000000


				6"	3 3/4"	2 1/2"	Fully Threaded	Coarse	170,000	ASTM A574	1	90044A232	000000
				8"	3 3/4"	2 1/2"	Partially Threaded	Coarse	170,000	ASTM A574	1	90044A233	000000
				10"	3 3/4"	2 1/2"	Partially Threaded	Coarse	170,000	ASTM A574	1	90044A234	000000

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.

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



	2 1/2"-4	Acme	12"	1	1:1	0.25"	Acme Class 2G	SAE Grade 2	Rockwell B61	64,000	ASTM A108	98935A785	000000


	2 1/2"-4	Acme	3 ft.	1	1:1	0.25"	Acme Class 2G	SAE Grade 2	Rockwell B61	64,000	ASTM A108	98935A901	000000
	2 1/2"-4	Acme	6 ft.	1	1:1	0.25"	Acme Class 2G	SAE Grade 2	Rockwell B61	53,000	ASTM A108	98935A215	000000


	Alloy Steel



			2 1/2"-4	Acme	3 ft.	1	1:1	0.25"	Acme Class 2G	ASTM Grade B7	Rockwell C35	125,000	ASTM A193	93410A681	000000

Coupling Nuts—Right-Hand Thread

Coupling nuts connect two lead screws.

Carbon Steel—Carbon steel components are easier to machine than alloy 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	Ht.	Wd.	No. of Thread Starts	Speed Ratio	Travel Distance per Turn	Thread Fit	Hardness	Tensile Strength		Each
Carbon Steel



	2 1/2"-4	Acme	5"	3 1/2"	1	1:1	0.25"	Acme Class 2G	Rockwell B75	Not Rated	93023A327	0000000

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.

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

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	Specs. Met		Each
Carbon Steel



	2 1/2"-4	Acme	2 1/2"	3 1/2"	1	1:1	0.25"	Acme Class 2G	Rockwell B75	Not Rated	—	94815A115	0000000


	Zinc-Plated Carbon Steel



			2 1/2"-4	Acme	2 1/2"	3 1/2"	1	1:1	0.25"	Acme Class 2G	Rockwell B75	Not Rated	—	98948A133	000000


			360 Brass



					2 1/2"-4	Acme	2 1/2"	3 1/2"	1	1:1	0.25"	Acme Class 2G	Rockwell B75	Not Rated	ASTM B16	95155A179	000000


					18-8 Stainless Steel



							2 1/2"-4	Acme	2 1/2"	3 1/2"	1	1:1	0.25"	Acme Class 2G	Rockwell B97	Not Rated	—	95066A195	000000

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.

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



	2 1/2"-4	3	Acme	1:1	1	0.25"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A065	0000000


	2 1/2"-4	6	Acme	1:1	1	0.25"	±0.009"/1 ft.	Acme Class 2C	Brinell 126	64,000	99030A165	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.

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



		2 1/2"-4	3 3/8"	3.375"	Acme	1:1	1	0.25"	3 9/64"-12	1 9/16"	Acme Class 2C	Brinell 70	Not Rated	Not Rated	95072A123	0000000

Flanges

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

1117 Carbon Steel—Carbon steel flanges have good machinability. However, they will rust when exposed to moisture.

	Flange Dia.	Flange Thk.	Bolt Circle Dia.	Flange Hardness		Each
1117 Carbon Steel



	3 9/64"-12	5 3/8"	1 37/64"	4 3/8"	Brinell 156	95082A647	0000000

Eyebolts—For Lifting

Also known as machinery eyebolts.

Note: Capacities listed are for vertical lifting only. Eyebolts with shoulder can be used for angular lifting up to 45°, but the capacities will be significantly reduced. For angular lifting, we recommend Hoist Rings. Eyebolts without shoulder are for vertical lifting only.

Warning: Never use to lift people or items over people.

Steel


Closed Eye With Shoulder	Closed Eye, Without Shoulder

Closed Eye—Closed eyes are stronger than bent-closed eyes.

	Thread							With Shoulder			Without Shoulder
	Size	Lg.	Shank Lg.	Eye Dia.	Vert. Cap., lb.	Specs. Met	Threading	Overall Lg.		Each	Overall Lg.		Each
Closed Eye



		2 1/2"-4	5"	5"	4 3/16"	56,000	ASTM A489	Fully Threaded	15 3/8"	3014T101	0000000	13 1/2"	3013T88	0000000

Zinc-Plated Steel


Closed Eye With Shoulder	Closed Eye, Without Shoulder

Zinc-plated steel eyebolts offer good corrosion resistance.

Closed Eye—Closed eyes are stronger than bent-closed eyes.

	Thread							With Shoulder			Without Shoulder
	Size	Lg.	Shank Lg.	Eye Dia.	Vert. Cap., lb.	Specs. Met	Threading	Overall Lg.		Each	Overall Lg.		Each
Closed Eye



		2 1/2"-4	5"	5"	4 3/16"	56,000	ASTM A489	Fully Threaded	15 3/8"	3014T194	0000000	13 1/2"	3013T17	0000000