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MS21042 All-Metal Hex Stop Nuts

74 Reviews 4 Answered Questions

From $0.36 to $1.24

Type	Part No.	Thread	Price	Buy
Dry Hex Nut	04-04060	4-40	$0.45	Quantity
Dry Hex Nut	MS21042-06	6-32	$0.57	Quantity
Dry Hex Nut	MS21042-08	8-32	$0.40	Quantity
Dry Hex Nut	MS21042-3	10-32	$0.36	Quantity
Dry Hex Nut	MS21042-4	1/4-28	$0.42	Quantity
Dry Hex Nut	MS21042-5	5/16-24	$1.14	Quantity
Dry Hex Nut	MS21042-6	3/8-24	$1.12	Quantity
Lubed Hex Nut	MS21042-L04	4-40	$0.41	Quantity
Lubed Hex Nut	MS21042-L06	6-32	$0.75	Quantity
Lubed Hex Nut	MS21042-L08	8-32	$0.48	Quantity
Lubed Hex Nut	MS21042-L3	10-32	$0.54	Quantity
Lubed Hex Nut	MS21042-L4	1/4-28	$0.59	Quantity
Lubed Hex Nut	MS21042-L5	5/16-24	$1.24	Quantity
Lubed Hex Nut	MS21042-L6	3/8-24	$1.14	Quantity

Subtotal $0.00

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Overview

The MS21042 all-metal stop nuts are designed for use in high temp installations (up to 450°F). MS21042 nuts are shorter than the AN363 nut but develop the same tensile strength. MS21042 Hex Nuts (Lubed) are the same as MS21042- but have a dry film lube (dark grey).


	WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov.

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Reviews

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Robert S

Verified Purchase

Nut, Stop MS21042-4

June 29, 2025

Robert S

Verified Purchase

Nut, Stop MS21042-5

June 29, 2025

Robert G

Verified Purchase

Nut, Stop MS21042-3

April 12, 2025

Fast response and top quality hardware!

Guilbert T

Verified Purchase

Nut, Stop MS21042-3

February 17, 2025

Sam C

Verified Purchase

Nut, Stop MS21042-3

November 15, 2024

Sam C

Verified Purchase

Nut, Stop MS21042-08

November 15, 2024

Sam C

Verified Purchase

MS21042-04 4-40 Thread Stop Nut

November 15, 2024

Sam C

Verified Purchase

Nut, Stop MS21042-06

November 15, 2024

Sam C

Verified Purchase

Nut, Stop MS21042-6

November 15, 2024

My nuts arrived promptly and were well packaged.

Marcus S

Verified Purchase

Nut, Stop MS21042-6

September 20, 2024

Tim H

Verified Purchase

Nut, Stop MS21042-3

September 13, 2024

Tim H

Verified Purchase

Nut, Stop MS21042-08

September 13, 2024

Tim H

Verified Purchase

Nut, Stop MS21042-4

September 13, 2024

It’s a self locking nut

Don E

Verified Purchase

Hex Nut MS21042-L06

September 11, 2024

Terry R

Verified Purchase

Nut, Stop MS21042-6

August 28, 2024

David

Verified Purchase

Nut, Stop MS21042-3

August 14, 2024

J-guy F

Verified Purchase

Nut, Stop MS21042-6

June 14, 2024

Roger P

Verified Purchase

Nut, Stop MS21042-6

May 2, 2024

as described

Roger P

Verified Purchase

Nut, Stop MS21042-5

May 2, 2024

Great pricing and quick shipping !

Arrowtec H

Verified Purchase

Hex Nut MS21042-L4

September 27, 2023

Great pricing and quick shipping !

Arrowtec H

Verified Purchase

Hex Nut MS21042L3

September 27, 2023

Parts as described, ordered on Friday picked up on Monday,

Kenneth M

Verified Purchase

Nut, Stop MS21042-6

August 29, 2023

Not having the correct hardware drives me nuts.

Jim P

Verified Purchase

Nut, Stop MS21042-4

June 15, 2023

Not having the correct hardware drives me nuts.

Jim P

Verified Purchase

Nut, Stop MS21042-5

June 15, 2023

nice product

David R

Verified Purchase

Nut, Stop MS21042-5

December 28, 2022

Mike S

Verified Purchase

Nut, Stop MS21042-3

December 27, 2022

Jim M

Verified Purchase

Nut, Stop MS21042-4

November 19, 2022

👍

Joachim S

Verified Purchase

Nut, Stop MS21042-3

September 12, 2022

Magaero L

Verified Purchase

Hex Nut MS21042-L4

August 26, 2022

Magaero L

Verified Purchase

Hex Nut MS21042L5

August 26, 2022

Works great on this application. Good quality!

Julio S

Verified Purchase

Nut, Stop MS21042-3

August 25, 2022

Magaero L

Verified Purchase

Hex Nut MS21042L5

August 12, 2022

This is the most amazing #4 nut youll ever meet.

David M

Verified Purchase

MS21042-04 4-40 Thread Stop Nut

May 8, 2022

good quality

Matthew P

Verified Purchase

Nut, Stop MS21042-6

April 1, 2022

Puddle J

Verified Purchase

Nut, Stop MS21042-6

March 25, 2022

Excellent, as advertised

Alan F

Verified Purchase

Nut, Stop MS21042-5

March 8, 2022

Works great in small places.

John B

Verified Purchase

Nut, Stop MS21042-06

February 12, 2022

As advertised MS stop nut on easy to navigate website.

Patrick C

Verified Purchase

Nut, Stop MS21042-08

January 21, 2022

Mark M

Verified Purchase

Nut, Stop MS21042-4

January 12, 2022

Mark M

Verified Purchase

Nut, Stop MS21042-6

January 12, 2022

Mark M

Verified Purchase

Nut, Stop MS21042-5

January 12, 2022

👍

Afelio S

Verified Purchase

Hex Nut MS21042L3

January 4, 2022

nice and quick

Lonny L

Verified Purchase

Nut, Stop MS21042-4

January 4, 2022

Exactly what needed to attach new driving dog to BMW airhead wheel.

Louis R

Verified Purchase

Nut, Stop MS21042-4

November 3, 2021

proper order... Thanks

James D

Verified Purchase

Nut, Stop MS21042-3

October 19, 2021

proper order... Thanks

James D

Verified Purchase

Nut, Stop MS21042-6

October 19, 2021

Great quality Hardware!

Westwood A

Verified Purchase

Nut, Stop MS21042-06

September 9, 2021

Great product

Ira H

Verified Purchase

Nut, Stop MS21042-3

August 27, 2021

Great product

Ira H

Verified Purchase

Nut, Stop MS21042-6

August 25, 2021

Perfect for the application they were needed for.

Ira H

Verified Purchase

Nut, Stop MS21042-3

August 11, 2021

Perfect for the application they were needed for.

Ira H

Verified Purchase

Nut, Stop MS21042-6

August 11, 2021

M &

Verified Purchase

Hex Nut MS21042L5

July 16, 2021

excellent quality as expected. thanks

Don L

Verified Purchase

Nut, Stop MS21042-4

July 8, 2021

Purchased these stop nuts for head nuts on Lycoming O-145 engine. Access is extremely tight. These worked perfectly.

Jackson M

Verified Purchase

Nut, Stop MS21042-5

July 3, 2021

Ronald M

Verified Purchase

Nut, Stop MS21042-3

June 24, 2021

Ronald M

Verified Purchase

Nut, Stop MS21042-4

June 24, 2021

Ronald M

Verified Purchase

Nut, Stop MS21042-06

June 24, 2021

Order shipped promptly, sales person very polite

Charles M

April 20, 2021

Great nut for small tight places and firewall forward where heat is an issue.

Lewis M

September 23, 2020

Use these on my race car to reduce weight and ensure a secure fit.

John

March 19, 2020

Highest quality, provides a light weight low profile locking fitting. Great for high heat applications.

John

February 29, 2020

Frederick C

November 11, 2019

As described. Recommended.

Ronald G

July 11, 2019

Michael D

February 28, 2019

Perfect! Great product and much cheaper than other manufacturers. This is my go to shop for my race car needs.

B B

February 18, 2019

Just what I needed.

Alan E

September 8, 2018

Steve S

August 27, 2018

widely used among F-1600 racers to ensure the AN bolts that match are held in place correctly- be careful not to over torque the smaller sizes

Danby C

May 10, 2018

Very Very good

Ruentech

August 7, 2017

Thank you so much

Ruentech

August 7, 2017

Standard MS nut. good quality

Thomas C

February 27, 2017

A+

Frank B

Verified Purchase

Nut, Stop MS21042-4

July 28, 2022

Did not receive the stop nuts in the box. Got everything else.

Doug R

August 8, 2019

Nut wasn’t what I needed, may have mis ordered so may be my fault.

Chris L

May 18, 2020

Q&A

Please note, Aircraft Spruce ®'s personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce ® assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Is MS21042-06 cad plated steel?

Yes, these are cad plated steel.

Q: What is the equivalent nut in Stainless Steel?

MS21043-4 (our part number 04-01388.)

Q: What is the reason for choosing a dry or lubed version of these Hex Nuts?

It helps prevent corrosion.

Q: Are these MS21042 ALL-METAL HEX STOP NUTS self locking?

Yes.

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