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

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—Best for dry environments since moisture will cause these screws to rust. They have a dark, matte appearance.

Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.

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







				2 1/2"-4

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


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

Heavy-Profile Hex Nuts

About 10% wider and taller than standard-profile hex nuts, these handle heavier loads by distributing them over a larger area.

Medium-Strength Steel

These Grade 5 or Class 8 nuts are your go-to for fastening most machinery and equipment. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.

Steel—Best for dry environments since moisture will cause these nuts to rust.

Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.

	Wd.	Ht.	Fastener Strength Grade/Class	Certificate Type	Pkg. Qty.		Pkg.
Steel



	2 1/2"-4	3 7/8"	2 29/64"	SAE Grade 5	Material Certificate	1	95045A049	000000

Extreme-Strength Steel

These nuts are about 20% stronger than high-strength steel nuts. To avoid stripped threads during installation, make sure your screw has a comparable strength rating.

Steel—Best for dry environments since moisture will cause these nuts to rust.

	Wd.	Ht.	Fastener Strength Grade/Class	Specs. Met	Pkg. Qty.		Pkg.
Steel



	2 1/2"-4	3 7/8"	2 29/64"	ASTM Grade 2H	ASME B18.2.2, ASTM A194	1	90521A283	000000

Eyebolts—For Lifting

Create a secure attachment point for hooks, shackles, and other lifting equipment. Also known as machinery eyebolts, these eyebolts are used to lift heavy machines and materials. They have a closed eye that won’t bend under strain.

Warning: Never use to lift people or items over people. Capacities listed are for vertical lifting only.

Steel


With Shoulder	Without Shoulder

With Shoulder—Use for lifting at angles up to 45° or for vertical lifting. Because angular lifting significantly reduces the eyebolt’s capacity, we recommend hoist rings for heavy loads.

Without Shoulder—For vertical lifting only.

	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	4 1/4"	5"	4"	56,000	ASTM A489	Fully Threaded	—	———	0	13 3/16"	3013T88	0000000


		2 1/2"-4	4 7/16"	5"	4"	56,000	ASTM A489	Fully Threaded	14 9/16"	3014T101	0000000	—	———	0

Zinc-Plated Steel


With Shoulder	Without Sholder

Zinc-plated steel eyebolts offer good corrosion resistance.

With Shoulder—Use for lifting at angles up to 45° or for vertical lifting. Because angular lifting significantly reduces the eyebolt’s capacity, we recommend hoist rings for heavy loads.

Without Shoulder—For vertical lifting only.

	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	4 1/4"	5"	4"	56,000	ASTM A489	Fully Threaded	—	———	0	13 3/16"	3013T17	0000000


		2 1/2"-4	4 7/16"	5"	4"	56,000	ASTM A489	Fully Threaded	14 9/16"	3014T194	0000000	—	———	0

Hex Nuts

The most commonly used hex nuts, these are suitable for fastening most machinery and equipment.

Low-Strength Steel

Rated Grade 2, Class 6, or lower, these nuts are about half as strong as medium-strength nuts. They are suitable for light duty fastening applications, such as securing access panels. Use them with screws that have a similar strength rating to avoid stripping threads during installation.

Steel—Best for dry environments since moisture will cause these nuts to rust.

	Wd.	Ht.	Fastener Strength Grade/Class	Specs. Met	Pkg. Qty.		Pkg.
Steel



	2 1/2"-4	3 3/4"	2 5/32"	SAE Grade 2	ASME B18.2.2	1	90490A051	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

Thin-Heavy-Profile Hex Nuts

About half the height of standard-profile hex nuts and 10% wider, these fit in spaces with low clearance and handle heavier loads by distributing them over a larger area. You can also use them as jam nuts by threading them against another hex nut to hold it in place.

Low-Strength Steel

Steel—Best for dry environments since moisture will cause these nuts to rust.

	Wd.	Ht.	Fastener Strength Grade/Class	Pkg. Qty.		Pkg.
Steel



	2 1/2"-4	3 7/8"	1 29/64"	SAE Grade 2	1	90502A049	000000

Thin-Profile Hex Nuts

About half the height of standard-profile nuts, these fit in spaces with low clearance. You can also use them as jam nuts by threading them against another hex nut to hold it in place.

Certificates with a traceable lot number are available for these products. Download certificates from ORDER HISTORY after your order ships.

Low-Strength Steel

Steel—Best for dry environments since moisture will cause these nuts to rust.

	Wd.	Ht.	Fastener Strength Grade/Class	Certificate Type	Pkg. Qty.		Pkg.
Steel



	2 1/2"-4	3 3/4"	1 13/32"	SAE Grade 2	Material Certificate	1	90496A068	000000

Hoist Rings—For Lifting

Designed for angular lifting, hoist rings resist stresses that would bend or break an eyebolt. They have a lifting ring that pivots 180° front to back and a base that swivels 360° to compensate for pitch, roll, and sway when lifting heavy or unbalanced loads. Install the base of the hoist ring flush to the mounting surface and tighten to the recommended torque that is stamped on the ring. Torque wrenches are sold separately.

Note: Capacities listed are for vertical lifting only. As the lift angle changes from vertical, the amount of weight the hoist ring can lift is significantly reduced. For example, when lifting a 1,000 lb. load at a 45° angle, you must choose a hoist ring with a capacity of at least 1,400 lbs. Do not use at an angle less than 30°.

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

Machined—Machined hoist rings have a smooth finish to protect slings and hooks from damage and excess wear during lifting.

Black-Oxide Steel—Black-oxide steel hoist rings have mild corrosion resistance.

CE Marked—Hoist rings that are CE marked meet European safety standards.

										Each
Thread Size	Thread Lg.	Inside Wd.	Overall Ht.	Vert. Cap., lb.	Movement	Specs. Met	Certification	Mil. Spec.		1-9	10-Up







			Machined Black-Oxide Steel

			2 1/2"-4	4"	6"	20 7/8"	50,000	180° Pivot and 360° Swivel	ASME B30.26	CE Marked, Mil. Spec.	MIL-STD-1365, MIL-STD-209	3052T75	000000000	000000000