Grade 8 Nuts | McMaster-Carr

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	Fastener Strength Grade/Class Fastener Strength Grade/Class


Grade 8	Class 8

	System of Measurement System of Measurement

Inch

Metric

	Thread Size Thread Size

	Thread Pitch Thread Pitch

	Nut Type Nut Type


Cap	Coupling

Flange	Hex

Locknut

	Hex Nut Profile Hex Nut Profile


Standard	Thin

Extra Wide	High

	Material Material

Steel

	Finish Finish

Black Oxide

Black Phosphate

Black Ultra-Corrosion-
Resistant Coated

Black Zinc Plated

Cadmium Yellow-Chromate
Plated

Phosphate Coated

Zinc Plated

Zinc Yellow-Chromate Plated

Zinc-Aluminum Coated

	Thread Direction Thread Direction


Right Hand	Left Hand

	Width Width

	Height Height

	Thread Spacing Thread Spacing

Coarse

Fine

Extra Fine

	Locking Type Locking Type


Nylon Insert	Serrations

Distorted Thread	Lock Washer

Cotter Pin	Steel Insert

	Specifications Met Specifications Met

	Thread Type Thread Type

	Thread Fit Thread Fit

Class 2B

Class 6H

	Drive Style Drive Style

	External Hex

	DFARS (Defense Acquisition Regulations Supplement) DFARS (Defense Acquisition Regulations Supplement)

DFARS Specialty Metals
COTS-Exempt

DFARS Specialty Metals
Compliant

	Flange Diameter Flange Diameter

	Insert Maximum Temperature Insert Maximum Temperature

220° F

250° F

Not Rated

	Flange Thickness Flange Thickness

	Length Length

	Threading Threading

	Fully Threaded

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1,092 Products

About Nuts, Materials, and Finishes

Metric Medium-Strength Steel Hex Nuts—Class 8

Class 8 nuts are comparable in strength to Class 8.8 bolts and are suitable for fastening most machinery and equipment.

Metric Fine-Thread Medium-Strength
Steel Hex Nuts—Class 8

Metric Left-Hand Threaded
Medium-Strength Steel Hex Nuts

These metric nuts tighten when turned to the left; once fastened, they resist loosening from counterclockwise motion.

JIS Medium-Strength Steel Hex Nuts

These metric nuts meet JIS (Japanese Industrial Standard) B 1181.

High-Strength Steel Hex Nuts—Grade 8

These nuts are about 25% stronger than medium-strength steel nuts.

Mil. Spec. High-Strength Steel Hex Nuts

Choose these nuts for their adherence to strict military standards for material and construction.

Left-Hand Threaded High-Strength Steel Hex Nuts

Tighten these nuts by turning them to the left; once fastened, they resist loosening from counterclockwise motion.

High-Strength Steel Hex Nuts with Material Test Report

These nuts come with a traceable lot number and a physical and chemical test report.

High-Strength Steel Thin Hex Nuts—Grade 8

These nuts are about 25% stronger than medium-strength steel thin hex nuts. Available in inch thread sizes.

Steel High Hex Nuts

With a height that is 50% taller than standard hex nuts, these nuts provide a larger gripping area for installation with a wrench.

Metric Steel High Hex Nuts

50% taller than standard hex nuts, these metric nuts provide a larger gripping area for installation with a wrench.

Locknuts

High-Strength Steel Nylon-Insert Locknuts—Grade 8

Includes inch thread sizes. These Grade 8 steel locknuts are 25% stronger than our medium-strength steel nylon-insert locknuts.

Metric Medium-Strength Steel
Nylon-Insert Locknuts—Class 8

Made from medium-strength steel with a nylon insert, these Class 8 metric locknuts are strong enough to use on most machinery and equipment that’s prone to vibration and temperature changes.

Metric Fine-Thread Medium-Strength
Steel Nylon-Insert Locknuts—Class 8

Get a grip on metric bolts exposed to vibration, wear, and changes in temperature. These metric locknuts have a nylon insert that holds onto bolts without damaging their threads.

High-Strength Steel Thin Nylon-Insert Locknuts

These Grade 8 locknuts are about 25% stronger than medium-strength steel thin locknuts.

Metric Steel Locknuts with External-Tooth Lock Washer

These metric locknuts have a free-spinning tooth lock washer that grips the material surface instead of threads for easy installation and mild vibration resistance.

Metric Steel Nonmarring Locknuts
with Spring-Lock Washer

A conical washer acts as a spring to add tension between the nut and the material surface for easy installation and mild vibration resistance. These metric locknuts have a smooth rim to resist scratching materials when tightened.

Metric Medium-Strength Steel Top-Lock
Distorted-Thread Locknuts—Class 8

These metric locknuts have an irregularly shaped thread at the top of the nut that grips the bolt for a stronger hold than nylon-insert locknuts.

High-Strength Steel Center-Lock
Distorted-Thread Locknuts—Grade 8

These Grade 8 locknuts are about three times stronger than low-strength steel distorted-thread locknuts.

Left-Hand Threaded High-Strength Steel
Center-Lock Distorted-Thread Locknuts—Grade 8

These locknuts tighten when turned to the left.

Metric Medium-Strength Steel Center-Lock
Distorted-Thread Locknuts—Class 8

Strong enough for use with most machinery and equipment, these Class 8 metric locknuts have an irregularly shaped thread in the middle of the nut that grips bolts tighter than nylon-insert locknuts.

Metric Medium-Strength Steel Locknuts
for use with Cotter Pins—Class 8

Secure these metric nuts by inserting a cotter pin or safety wire through the slots and a drilled hole in your bolt for mild loosening resistance. Often referred to as castle nuts.

Metric Steel-Insert Locknuts
for Extreme Vibration—Class 8

The metric steel insert grips the threads and lifts away from the nut body when installed, isolating the insert from the nut's load to resist spinoff caused by vibration.

High-Strength Steel Extra-Wide Steel-Insert
Locknuts for Extreme Vibration—Grade 8

High-strength steel locknuts are about 25% stronger than medium-strength steel locknuts.

Thin Steel-Insert Locknuts for Extreme Vibration

About two-thirds the height of standard steel-insert locknuts, use these locknuts in low-clearance applications or jam one against a hex nut to hold it in place.

Flange Nuts

Metric Medium-Strength Steel
Serrated Flange Locknuts—Class 8

Strong enough for use in most machinery and equipment, these medium-strength metric nuts have serrations on the underside of the flange. The serrations prevent the nuts from loosening in applications with mild vibration.

High-Strength Steel Serrated
Flange Locknuts—Grade 8

These nuts are about 25% stronger than medium-strength steel flange locknuts.

Metric Medium-Strength Steel
Nylon-Insert Flange Locknuts—Class 8

High-Strength Steel Flange Nuts—Grade 8

Made from Grade 8 steel, these nuts are about 25% stronger than medium-strength steel flange nuts.

Metric Medium-Strength Steel Flange Nuts—Class 8

No need for a washer—these metric medium-strength steel nuts have a flange that distributes pressure across its surface the way a washer does. Made of medium-strength, Class 8 steel, they’re suitable for fastening most machinery and equipment.

JIS Medium-Strength Steel Flange Nuts

Made to Japanese Industrial Standards, these nuts fasten most Japanese machinery and equipment without a washer.

High-Strength Steel Cap Nuts—Grade 8

These nuts are about 25% stronger than medium-strength steel cap nuts.

Steel Coupling Nuts

Metric Medium-Strength Steel Coupling Nuts—Class 8

Choose these locknuts to fasten standard metric threads. They’re Class 8 steel, so they can be used in most fastening applications.

High-Strength Steel Coupling Nuts—Grade 8

Made from Grade 8 steel, these nuts are about 25% stronger than medium-strength steel coupling nuts. Furnished in inch thread sizes.

About Nuts, Materials, and Finishes

Hex Nuts

Metric Medium-Strength Steel Hex Nuts—Class 8

Metric Fine-Thread Medium-StrengthSteel Hex Nuts—Class 8

Metric Left-Hand ThreadedMedium-Strength Steel Hex Nuts

JIS Medium-Strength Steel Hex Nuts

High-Strength Steel Hex Nuts—Grade 8

Mil. Spec. High-Strength Steel Hex Nuts

Left-Hand Threaded High-Strength Steel Hex Nuts

High-Strength Steel Hex Nuts with Material Test Report

High-Strength Steel Thin Hex Nuts—Grade 8

Steel High Hex Nuts

Metric Steel High Hex Nuts

Locknuts

High-Strength Steel Nylon-Insert Locknuts—Grade 8

Metric Medium-Strength SteelNylon-Insert Locknuts—Class 8

Metric Fine-Thread Medium-StrengthSteel Nylon-Insert Locknuts—Class 8

High-Strength Steel Thin Nylon-Insert Locknuts

Metric Steel Locknuts with External-Tooth Lock Washer

Metric Steel Nonmarring Locknutswith Spring-Lock Washer

Metric Medium-Strength Steel Top-LockDistorted-Thread Locknuts—Class 8

High-Strength Steel Center-LockDistorted-Thread Locknuts—Grade 8

Left-Hand Threaded High-Strength SteelCenter-Lock Distorted-Thread Locknuts—Grade 8

Metric Medium-Strength Steel Center-LockDistorted-Thread Locknuts—Class 8

Metric Medium-Strength Steel Locknutsfor use with Cotter Pins—Class 8

Metric Steel-Insert Locknutsfor Extreme Vibration—Class 8

High-Strength Steel Extra-Wide Steel-InsertLocknuts for Extreme Vibration—Grade 8

Thin Steel-Insert Locknuts for Extreme Vibration

Flange Nuts

Metric Medium-Strength SteelSerrated Flange Locknuts—Class 8

High-Strength Steel SerratedFlange Locknuts—Grade 8

Metric Medium-Strength SteelNylon-Insert Flange Locknuts—Class 8

High-Strength Steel Flange Nuts—Grade 8

Metric Medium-Strength Steel Flange Nuts—Class 8

JIS Medium-Strength Steel Flange Nuts

High-Strength Steel Cap Nuts—Grade 8

High-Strength Steel Cap Nuts—Grade 8

Steel Coupling Nuts

Metric Medium-Strength Steel Coupling Nuts—Class 8

High-Strength Steel Coupling Nuts—Grade 8

Hex Nut Assortments

Hex Nut Assortments

Metric Fine-Thread Medium-Strength
Steel Hex Nuts—Class 8

Metric Left-Hand Threaded
Medium-Strength Steel Hex Nuts

Metric Medium-Strength Steel
Nylon-Insert Locknuts—Class 8

Metric Fine-Thread Medium-Strength
Steel Nylon-Insert Locknuts—Class 8

Metric Steel Nonmarring Locknuts
with Spring-Lock Washer

Metric Medium-Strength Steel Top-Lock
Distorted-Thread Locknuts—Class 8

High-Strength Steel Center-Lock
Distorted-Thread Locknuts—Grade 8

Left-Hand Threaded High-Strength Steel
Center-Lock Distorted-Thread Locknuts—Grade 8

Metric Medium-Strength Steel Center-Lock
Distorted-Thread Locknuts—Class 8

Metric Medium-Strength Steel Locknuts
for use with Cotter Pins—Class 8

Metric Steel-Insert Locknuts
for Extreme Vibration—Class 8

High-Strength Steel Extra-Wide Steel-Insert
Locknuts for Extreme Vibration—Grade 8

Metric Medium-Strength Steel
Serrated Flange Locknuts—Class 8

High-Strength Steel Serrated
Flange Locknuts—Grade 8

Metric Medium-Strength Steel
Nylon-Insert Flange Locknuts—Class 8