Part# AN7-52
MFR Model# 12599-1
Dash No.Nominal


Hex head aircraft bolts are made of high-strength type 4037 or 8740 alloy steel (type 8740 is most commonly used). The bolts are centerless ground and threaded after heat treatment. Minimum tensile strength 125,000 PSI. Cadmium plated per specification QQ-P-416A, Type II, Class 3. Available with shank drilled for cotter pin or undrilled for stop nut application, and with or without drilled head for safety wire. Specify bolts to have undrilled shank by adding letter "A" after the dash number. For bolts with drilled head add letter "H" after the AN number. See illustrated examples. "C" represents Type 431 Stainless Steel (contains iron which is magnetic). The length of AN aircraft bolts is measured from under the head to the end of the shank. The "grip" is the unthreaded portion of the shank. See table for conversion of length and/or grip to proper AN callout.

Note: Drilled bolts listed above are drilled shank only. To order drilled head only or both drilled head and shank bolts, please use our AN Bolt Selector by clicking the link below.

Click here for the AN Bolt Selector
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -

Reference Chart

Reference Chart


Prop bolts for my airboat.

George F
April 13, 2021

Aircraft Spruce is always a constant, and reliable source for what I need. Products are always of good quality. Shipping, well, I’m sure Aircraft Spruce has little latitude in that area.

Charles M
February 22, 2021

Cadmium bolts.... they work as theyre supposed to.

Jose G
February 5, 2021

Was able to pick the bolts I needed, showed up perfect!

Zac J
January 4, 2021

These are the prettiest AN6H-6A Bolts I have ever seen.

Robert S
November 30, 2020

You kept shipping costs down. Great!

John M
October 16, 2020


Jerry C
September 22, 2020

Cant beat real AN hardware. Very well packaged from Aircraft Spruce. I use these type bolts on race cars to eliminate failures, never lets me down.

Neil C
August 20, 2020

the only thing I would change is a faster shipping method .

Charles T
June 5, 2020

Good quality

Joe B
May 11, 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: What is the diameter tolerance on a 3/8-24 AN bolt?

The max is .374", and min .371"

Q: We are wanting to order AN7-43A bolts for mounting the engine in a Cessna 172. What size steel locking nuts do we need to order with these bolts?

AN7 bolts have 7/16-20 threads, so the nut would also have to have the same thread size. Please refer to the aircraft parts manual for the style of nut Cessna recommends for this application.

Q: What is the safety wire diameter recommended for the drilled version?

It depends on the application, but both .032 and .041 will fit through the hole.

Q: On a drilled shank, where is the hole located in reference to the end?

Per the Tech Data Sheet, the hole location is determined from the start of the threads, on the head side, to the center of the drilled hole. AN3 = 17/64", AN4 = 5/16", AN5 = 23/64", AN6 = 7/16", AN7 = 31/64", AN8 = 39/64".

Q: What is the difference between stainless and cadmium plated AN bolts?

Stainless bolts are corrosion resistant for applications where corrosion is a problem. CAD plated bolts are made of steel with CAD plating to help surface corrosion, but it can been worn or chipped off.

Q: Is the nominal length listed the entire bolt (head, grip and thread) or just the grip and thread?

The nominal length is the length from under the head to the end of the shank.

Q: Picture clearly shows a bolt with both head drilled and shank drilled, but bolt selector does not allow that choice?

We do offer all of the types shown, but unfortunately not in every size. For example, drilled head is not available in AN4-3 stainless, but is available in AN5-4 cadmium.

Q: For the drilled shank, what is diameter of the drilled hole on AN3?

It is drilled for 1/16" cotter pin so it will be slightly larger than 1/16".

Q: what is the diameter of an4 bolt?


Q: How do you measure the grip length?

The grip length is the unthreaded portion on the bolt.

View in Catalog

View Image View in Catalog