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MS21042 Style B Jetnut, All Metal Locknut

If you prefer the original style (which allow easier wrench access), we still have some available in -3, -4 and -5 sizes. They are about 40% less expensive.

MS21042 Jetnuts (Kaynuts) are all-metal, self-locking nuts. They are rated at 160,000 psi tensile strength and can withstand temperatures to 450°F. Because of their reduced hex dimension, they are widely used in limited space applications where wrench access is a problem. These are the latest "Style B" specification, with a slightly thicker flange which reduces the likelihood of splitting due to nut dilation (especially if over-torqued). Plated mild steel construction; some lots have a moly lubricant coating over the plating at the manufacturer's discretion (sorry, no choice on our end). Sold individually.

Jetnuts are also lighter than AN365 Nylon Lock Nuts (an average of 63% lighter for -3 through -6 sizes). Replacing all of the AN365 nuts on your racecar with MS21042 jetnuts can result in a measurable weight savings!

MS21042 Specifications
Dash No.	SAE Thread	Hex Size*	Outside Diameter	Height (Max)
L04	4-40	5/32"	0.206"	0.125"
06	6-32	3/16"	0.244"	0.141"
08	8-32	7/32"	0.290"	0.188"
3	10-32	1/4"	0.330"	0.188"
4	1/4-28	5/16"	0.420"	0.219"
5	5/16-24	3/8"	0.520"	0.266"
6	3/8-24	7/16"	0.620"	0.282"
7	7/16-20	1/2"	0.708"	0.328"
8	1/2-20	9/16"	0.814"	0.410"
L10	5/8-18	3/4"	1.014"	0.550"

* The hex is typically deformed to produce the self-locking action. An unused nut may appear to have one hex dimension smaller than the others before installation.

Looking for metric sizes? We also offer (non-milspec) Metric Jetnuts which have similar temperature and strength ratings.

Reusing Locking Nuts
The FAA has issued guidelines on the reuse of locking nuts. Specific recommendations have been published for larger sizes (7/16-20 and up), but the general rule is that you should not be able to turn the nut by hand once the locking portion engages the male threads. If you can turn the nut with your fingers, it must be replaced. When in doubt, replace!

Enter desired order quantities below, then click the "Add selected quantities to cart" button.

Order Qty

Part No.

Desc.

Price

Status

MS21042-04
Condition: New
SKU: 52845

4-40 Jetnut, All Metal Locknut

1 to 11: $0.79 12 to 149: $0.70 150 & up: $0.60

In Stock

MS21042-06
Condition: New
SKU: 47810

6-32 Jetnut, All Metal Locknut

1 to 11: $0.39 12 to 149: $0.35 150 & up: $0.30

In Stock

MS21042-08
Condition: New
SKU: 47811

8-32 Jetnut, All Metal Locknut

1 to 11: $0.44 12 to 149: $0.39 150 & up: $0.33

In Stock

MS21042-3
Condition: New
SKU: 33672

10-32 Jetnut, All Metal Locknut

1 to 11: $0.27 12 to 149: $0.24 150 to 1999: $0.20 2000 & up: call

In Stock

MS21042-4
Condition: New
SKU: 33673

1/4-28 Jetnut, All Metal Locknut

1 to 11: $0.64 12 to 149: $0.57 150 to 1999: $0.49 2000 & up: call

In Stock

MS21042-5
Condition: New
SKU: 33674

5/16-24 Jetnut, All Metal Locknut

1 to 11: $0.99 12 to 149: $0.90 150 to 1999: $0.80 2000 & up: call

In Stock

MS21042-6
Condition: New
SKU: 33675

3/8-24 Jetnut, All Metal Locknut

1 to 9: $1.19 10 to 99: $1.08 100 to 999: $0.97 1000 & up: call

In Stock

MS21042-7
Condition: New
SKU: 33676

7/16-20 Jetnut, All Metal Locknut

1 to 7: $4.69 8 & up: $4.30

In Stock

MS21042-8
Condition: New
SKU: 33677

1/2-20 Jetnut, All Metal Locknut

1 to 7: $5.39 8 to 59: $4.86 60 to 499: $4.32 500 & up: call

In Stock

MS21042-10
Condition: New
SKU: 48469

5/8-18 Jetnut, All Metal Locknut, Moly Coated

1 to 5: $19.99 6 to 35: $18.19 36 & up: $16.39

In Stock

Customers who purchased this item also purchased
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MS21042 Style B Jetnut, All Metal Locknut

Order Qty

Part No.

Desc.

Price

Status

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Related Product Groups

Airframe (AN) & Mil-Spec (MS) Nuts

AN and MS Nuts, AN and MS Washers, and AN Bolts