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NUT, STOP MS21042-5

Packaged Items
SinglePack of 10
TypePart No.Thread
Dry Hex NutMS21042-55/16-24


The MS21042 all-metal stop nuts are designed for use in high temp installations (up to 450F). 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).

Less 20% for quantity 100/Part No.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


as described

Roger P Verified Purchase

NUT, STOP MS21042-5

May 2, 2024

Goods received as ordered Thank you

Frazer Verified Purchase

NUT, STOP MS21042-5 (PACK OF 10)

November 3, 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

Todd B Verified Purchase

NUT, STOP MS21042-5 (PACK OF 10)

September 24, 2022

Excellent, as advertised

Alan F Verified Purchase

NUT, STOP MS21042-5

March 8, 2022

Mark M Verified Purchase

NUT, STOP MS21042-5

January 12, 2022

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

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


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?


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