M25 Fasteners | McMaster-Carr

To select the best shock absorber for your application, you need to find the energy capacity your application requires. Use this formula to calculate the energy capacity required to stop a horizontal-moving load. For example, if you have a 250-lb. load moving at 25 inches per second, your calculation is (250 lbs. ÷ 772) × 25² = 202.4 in.-lbs. energy capacity.

Note: Choose a shock absorber with a higher energy capacity than you calculated. Factors such as driving force or an inclined surface will increase the energy capacity required.

Energy Capacity (in.-lbs.) = (Weight, lbs./772) × Velocity² (in. per second)

Bearing Retaining Locknuts

Carbon Steel

Stainless Steel

Zinc-Plated Steel

With a nylon insert that grips your threaded shaft or spindle without damaging the threads, these locknuts—sometimes called shaft nuts—keep bearings, bushings, gears, and pulleys in place. They won’t shake loose from vibration. However, their nylon insert also means you shouldn’t use these locknuts in applications with high temperatures. Their sides are slotted, so you can tighten and loosen them with a spanner wrench or spanner socket. To reduce the total size and weight of your assembly, they have chamfered edges.

All meet international standards for bearing locknut dimensions.

Carbon steel locknuts are strong and wear resistant. Zinc-plated steel locknuts have an outer layer of zinc that prevents the steel from rusting in wet areas. Compared to stainless steel, they're stronger, more wear resistant, and less costly, but not as corrosion resistant. Avoid exposing them to salt water and chemicals. 303 stainless steel locknuts are nearly as strong as carbon steel but won’t rust in outdoor, washdown, and other corrosive environments.

When choosing your thread spacing, consider the precision of your application. The finer the threads, the more control you have when making adjustments.

For technical drawings and 3-D models, click on a part number.

Metric

Locknuts
Thread									Spanner Sockets
Size	Pitch, mm	Spacing	OD	Wd., mm	Insert Max. Temp., °F	Specifications Met		Each		Each
Carbon Steel
Chamfered Face
M25	1.5	Extra Fine	38mm	11	160°	ISO 2982-2	0000000	000000	00000000	0000000
Zinc-Plated Carbon Steel
Chamfered Face
M25	1.5	Extra Fine	38mm	10.5	210°	DIN 1805	0000000	00000	000000	00
303 Stainless Steel
Chamfered Face
M25	1.5	Extra Fine	38mm	11	160°	ISO 2982-2	0000000	00000	00000000	000000

Bearing Retaining Nuts

For Chamfered Nuts

Often paired with spring lock washers to strengthen their hold, these retaining nuts—also known as shaft nuts—keep vibration from shifting bearings, bushings, pulleys, and gears on your threaded shaft or spindle. They have slotted sides, so you can tighten and loosen them with a spanner wrench or spanner socket. Made of carbon steel, they’re strong and wear resistant.

Use stepped-face retaining nuts with DIN 462 spring lock washers. You can also use them in pairs or with other bearing retaining nuts as jam nuts. For the nut closer to the bearing, position the stepped face towards the bearing. All meet DIN standards for bearing lockout dimensions.

Chamfered-face retaining nuts weigh less and produce less heat than stepped-face nuts. They meet ISO 2982 (formerly DIN 981), an international standard for bearing locknut dimensions. Their sizes correspond to SKF KM series. Use them with DIN 5406 spring lock washers.

For technical drawings and 3-D models, click on a part number.

Nuts
Thread									Optional Washers		Spanner Sockets
Size	Pitch, mm	Spacing	OD, mm	Wd., mm	Specifications Met	For Lock Washer Specifications Met		Each		Each		Each
Carbon Steel
Chamfered Face
M25	1.5	Extra Fine	38	7	DIN 981, ISO 2982	DIN 5406	0000000	00000	000000000	00000	00000000	0000000

Metric Precision Ball Screws and Nuts

Precision cut threads make these metric ball screws approximately four times more accurate than standard ball screws. Use them when exact positioning is essential. They come with finished ends and the nut already on, so they’re ready to use right away. The ball nuts have a flange design that makes it easy to mount objects on them. Inside, they have ball bearings to produce smooth, low-friction travel for applications that require high-speed and repeatable movement.

Ball nuts with a travel distance per trun greater than 1 mm have a seal that prevents some contaminants from getting inside them. However, to make sure they don’t create torque and heat, there’s a bit of clearance between the seal and screw, so the seal can’t keep out everything.

Ball nuts with end caps dampen the noise from the ball bearings and make the ball nuts more compact.

Root diameter indicates the diameter the ball screw will be after machining away the threads.

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

For technical drawings and 3-D models, click on a part number.

	Ball Screw		Flange Ball Nut
Thread Size	Lg., mm	Root Dia., mm	Lg., mm	Dia., mm	No. of Thread Starts	Travel Distance per Turn, mm	Accuracy for Travel Distance per Turn	Hardness	Dynamic Thrust Load Cap., lbs.	Max. Backlash, mm	Includes	Temp. Range, °F		Each
Carbon Steel Ball Screw with Alloy Steel Flange Ball Nut
M25	751	21.9	53	47	2	20	±0.023 mm per 300 mm	Rockwell C58	2,350	0	End Caps	Not Rated to 175°	00000000	000000000
M25	851	21.9	53	47	2	20	±0.023 mm per 300 mm	Rockwell C58	2,350	0	End Caps	Not Rated to 175°	00000000	00000000
M25	1,051	21.9	53	47	2	20	±0.023 mm per 300 mm	Rockwell C58	2,350	0	End Caps	Not Rated to 175°	00000000	00000000
M25	1,251	21.9	53	47	2	20	±0.023 mm per 300 mm	Rockwell C58	2,350	0	End Caps	Not Rated to 175°	00000000	00000000
M25	1,451	21.9	53	47	2	20	±0.023 mm per 300 mm	Rockwell C58	2,350	0	End Caps	Not Rated to 175°	00000000	00000000
M25	1,651	21.9	53	47	2	20	±0.023 mm per 300 mm	Rockwell C58	2,350	0	End Caps	Not Rated to 175°	00000000	00000000
M25	1,851	21.9	53	47	2	20	±0.023 mm per 300 mm	Rockwell C58	2,350	0	End Caps	Not Rated to 175°	00000000	00000000

Metric Fast-Travel Ball Screws and Nuts

With multiple thread starts, these metric ball screws create linear travel that’s approximately three times faster than ball screws with a single thread start. They’re ideal for applications with an actuator. The ball nuts have internal ball bearings to produce smooth, low-friction travel for applications that require high speed, accurate positioning, and repeatable movement. They come with a tube to keep the ball bearings in place. Do not remove the tube until you’re ready to install the nuts onto the screws. All of these ball nuts have an end cap on each end to stabilize fast-rotating motion. End caps also dampen the noise from the ball bearings and make the ball nuts more compact. Seals on the ball nuts keep out dust.

To ensure compatibility, select components that have the same thread size and travel distance per turn.

Ball nuts with four mounting holes have a lower profile than ball nuts with six mounting holes, so they’re better when assembly height clearance is tight.

Ball nuts with six mounting holes have a support bearing for greater axial rigidity than ball nuts with four mounting holes. They’re responsive to motor and actuator movements.

Root diameter indicates the diameter the ball screw will be after machining away the threads.

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

For technical drawings and 3-D models, click on a part number.

Ball Screws—Right-Hand Threaded

Carbon Steel
Thread Size	Lg., mm	No. of Thread Starts	Travel Distance per Turn, mm	Accuracy for Travel Distance per Turn	Root Dia., mm	Hardness	Temp. Range, °F		Each
M25	500	4	25	±0.210 mm per 300 mm	21.9	Rockwell C58	Not Rated to 175°	00000000	0000000
M25	1,000	4	25	±0.210 mm per 300 mm	21.9	Rockwell C58	Not Rated to 175°	0000000	000000
M25	1,500	4	25	±0.210 mm per 300 mm	21.9	Rockwell C58	Not Rated to 175°	00000000	000000
M25	2,000	4	25	±0.210 mm per 300 mm	21.9	Rockwell C58	Not Rated to 175°	00000000	000000
M25	2,500	4	25	±0.210 mm per 300 mm	21.9	Rockwell C58	Not Rated to 175°	00000000	000000
M25	3,000	4	25	±0.210 mm per 300 mm	21.9	Rockwell C58	Not Rated to 175°	00000000	000000

Style A Flange Ball Nuts—Right-Hand Threaded

			Flange
Thread Size	Lg., mm	Dia., mm	Wd., mm	Ht., mm	Thick., mm	No. of Thread Starts	Travel Distance per Turn, mm	No. of Mounting Holes	Hardness	Dynamic Thrust Load Cap., lbs.	Max. Backlash, mm	Includes	Temp. Range, °F		Each
Alloy Steel
M25	55	47	74	56	12	4	25	4	Rockwell C58	2,710	0.1	End Caps Seals	Not Rated to 175°	00000000	0000000
M25	55	47	74	56	12	4	25	4	Rockwell C58	4,920	0.1	End Caps Seals	Not Rated to 175°	00000000	000000

Style B Flange Ball Nuts—Right-Hand Threaded

			Flange
Thread Size	Lg., mm	Dia., mm	Dia., mm	Thick., mm	No. of Thread Starts	Travel Distance per Turn, mm	No. of Mounting Holes	Bolt Circle Dia., mm	Hardness	Dynamic Thrust Load Cap., lbs.	Max. Backlash, mm	Includes	Temp. Range, °F		Each
Alloy Steel
M25	65	72	92	8	4	25	6	81	Rockwell C58	2,710	0.1	End Caps Seals	Not Rated to 175°	0000000	0000000

Metric Ball Screws and Nuts

Internal ball bearings provide smooth low-friction travel in applications that require high speeds, accurate positioning, and repeatable movement. Also known as single-start ball screws and nuts, these have a single thread that runs the length of the screw. They operate with more torque than fast-travel ball screws and nuts. To ensure compatibility, select components that have the same thread size and travel distance per turn. Ball nuts are furnished with a tube to keep ball bearings in place. Do not remove the tube until you are ready to install the nuts onto the screws.

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

For technical drawings and 3-D models, click on a part number.

Ball Screws—Right-Hand Threaded

Root diameter indicates the diameter the ball screw will be after machining away the threads.

Carbon Steel
Thread Size	Lg., mm	No. of Thread Starts	Travel Distance per Turn, mm	Accuracy for Travel Distance per Turn	Root Dia., mm	Hardness	Tensile Strength, psi	Temperature Range, °F		Each
M25	500	1	5	±0.210 mm per 300 mm	22.2	Rockwell C58	21,000	5° to 175°	0000000	0000000
M25	500	1	10	±0.210 mm per 300 mm	20.2	Rockwell C58	__	Not Rated to 175°	00000000	000000
M25	1,000	1	5	±0.210 mm per 300 mm	22.2	Rockwell C58	21,000	5° to 175°	0000000	000000
M25	1,000	1	10	±0.210 mm per 300 mm	20.2	Rockwell C58	__	Not Rated to 175°	00000000	000000
M25	1,500	1	5	±0.210 mm per 300 mm	22.2	Rockwell C58	__	Not Rated to 175°	00000000	000000
M25	1,500	1	10	±0.210 mm per 300 mm	20.2	Rockwell C58	21,000	5° to 175°	0000000	000000
M25	2,000	1	5	±0.210 mm per 300 mm	22.2	Rockwell C58	__	Not Rated to 175°	0000000	000000
M25	2,000	1	10	±0.210 mm per 300 mm	20.2	Rockwell C58	__	Not Rated to 175°	00000000	000000

Platform Ball Nuts—Right-Hand Threaded

Alloy Steel
Thread Size	Lg., mm	Wd., mm	Ht., mm	Center Ht., mm	No. of Thread Starts	Travel Distance per Turn, mm	Hardness	Dynamic Thrust Load Cap., lbs.	Max. Backlash, mm	Temperature Range, °F		Each
M25	35	60	45	20	1	5	Rockwell C58	1,500	0.1	5° to 175°	0000000	0000000
M25	94	60	55	23	1	10	Rockwell C58	7,000	0.1	5° to 175°	0000000	000000

Flange Ball Nuts—Right-Hand Threaded

			Flange
Thread Size	Lg., mm	Dia., mm	Wd., mm, mm	Ht., mm	Thick., mm	No. of Thread Starts	Travel Distance per Turn, mm	Hardness	Dynamic Thrust Load Cap., lbs.	Max. Backlash, mm	Temperature Range, °F		Each
Alloy Steel
M25	40	43	67	50	10	1	5	Rockwell C58	1,500	0.1	5° to 175°	0000000	0000000
M25	98	60	96	72	15	1	10	Rockwell C58	7,000	0.1	5° to 175°	0000000	000000

Locknuts for Plastic Conduit Fittings

Nylon

Secure threaded plastic conduit fittings to a knockout in an outlet box or enclosure.

For technical drawings and 3-D models, click on a part number.

	Black		Gray
Thread Size		Each		Each
Nylon
Metric Threads
M25	00000000	00000	00000000	00000

Locknuts for Metal Conduit Fittings

Zinc-Plated Steel, 304 Stainless
Steel, 316 Stainless Steel,
Aluminum, and Brass

Secure threaded metal conduit fittings to a knockout in an outlet box or enclosure.

For technical drawings and 3-D models, click on a part number.

304 Stainless Steel
Thread Size	Specifications Met		Each
Metric Threads
M25	DIN EN 1.4305	00000000	000000
Brass
Metric Threads
M25	DIN EN 60204	00000000	0000

Mounting Nuts for Shock Absorbers

Hex Nut

Use Mounting Blocks for Shock Absorbers (not included) to mount and secure threaded-body shock absorbers.

		Steel
Thread Size	Thread Pitch, mm		Each
Hex Nut
M25	1.5	0000000	00000