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Aircraft bolt head markings

B

Bavafa

Well Known Member
Just wondering if anyone can recognize this marking and if this is a genuine AN bolt. I have never seen this marking and could not find anything on the Web for it.

 
The little asterisk in the center is the key.

This link helps - http://cardinalmfg.com/Uploads/AN_Bolts.pdf

....Aircraft bolts may be identified by code markings on the bolt heads. These markings generally denote the material of which the bolt is made, whether the bolt is a standard AN-type or a special-purpose bolt, and sometimes include the manufacturer.
AN standard steel bolts are marked with either a raised cross or asterisk [most of those pictured], corrosion resistant steel is marked by a single dash [row 1, number 4], and AN aluminum-alloy bolts are marked with two raised dashes [row 3, number 5]....

The other letters are simply an optional code for the actual manufacturer and not a part of the AN markings.
 
Thank you Gil, I had noticed the asterisk, it just I had not seen it this way. Usually I see a X.
 
Out of curiosity

Look at the tail of the bolt. You should see a small indentation where a hardness test was done. You won?t see this test mark on regular ?commercial? grade boots.
 
Freemasm said:
Look at the tail of the bolt. You should see a small indentation where a hardness test was done. You won?t see this test mark on regular ?commercial? grade boots.
Click to expand...

Our low cost AN bolts are 100% tested for hardness?

I would have thought it would be only a few on a lot sampling basis, especially give the cost.
 
I was told this several decades ago by someone I trust. I’m waiting for some experts to reply here. In my ex-space industry days, every MS/NAS/AN/etc bolt had the marks on both ends verified at critical installations. All the left overs from that industry have them. Going to check my Spruce purchased ones for consistency. I know the testing standard but can’t tell you how/how often it’s applied. As mentioned, I hope so someone with the correct knowledge chimes in.
 
Freemasm said:
I was told this several decades ago by someone I trust. I?m waiting for some experts to reply here. In my ex-space industry days, every MS/NAS/AN/etc bolt had the marks on both ends verified at critical installations. All the left overs from that industry have them. Going to check my Spruce purchased ones for consistency. I know the testing standard but can?t tell you how/how often it?s applied. As mentioned, I hope so someone with the correct knowledge chimes in.
Click to expand...

That doesn't surprise me. The generic AN bolt specs call for the material used to specified in the procurement documents.

In the high $$$ space industry I'm sure they did call out for 100% parts testing but I'm pretty certain Aircraft Spruce and Vans are not doing that for a 10 cent AN3-3 bolt :D
 
I got at least one threaded fastener in my -7 my kit that wasn't.

So they might check every piece for hardness, but they sure don't check every one for function.
 
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