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Are these nut fittings different?

skelrad

Well Known Member
Friend
I have some nut fittings, flare couplings, etc that have AN info stamped on them and some that don't. I'm trying to figure out if they are indeed different and what they are appropriate for if they are. They either have "AN D IM" stamped on it, or nothing.
 

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Brandon, the nut on the right is a true AN certified aluminum nut. The one on the left, as viewed in the pic is not. Even the machining is different.

Now there are some imposter nuts out there , but do not have the higher strength class 3 threads. AN nuts are from 2024T3 aluminum, and the new 'W' spec is 7075-T73. Most of the imposters are 6061T6.

Tom
 
Brandon, the nut on the right is a true AN certified aluminum nut. The one on the left, as viewed in the pic is not. Even the machining is different.

Now there are some imposter nuts out there , but do not have the higher strength class 3 threads. AN nuts are from 2024T3 aluminum, and the new 'W' spec is 7075-T73. Most of the imposters are 6061T6.

Tom

Gotcha. The unmarked nuts came with my wing kit, whereas the marked ones just came in the fuselage kit.
 
stronger

Brandon, the nut on the right is a true AN certified aluminum nut. The one on the left, as viewed in the pic is not. Even the machining is different.

Now there are some imposter nuts out there , but do not have the higher strength class 3 threads. AN nuts are from 2024T3 aluminum, and the new 'W' spec is 7075-T73. Most of the imposters are 6061T6.

Tom

I think 7075 is so much stronger than 2024 or 6061. 7075 series is nearly as strong as steel if I recall correctly.
 
I seemed to have gotten some of those types of nuts also. I'm not sure if they came from Vans or ACS. What I decided is if the nut doesn't have AN markings stamped on it I'm not going to use it. This may be overkill, but it makes me feel better.
 
I seemed to have gotten some of those types of nuts also. I'm not sure if they came from Vans or ACS. What I decided is if the nut doesn't have AN markings stamped on it I'm not going to use it. This may be overkill, but it makes me feel better.

Mine came from Van's in a wing kit I purchased used (the kit was a few years old). I used the nuts and fittings in the tanks.
 
They are probably fine. I may even have some of those in parts that I did earlier in the build. Once I realized that some parts may not be actual AN spec parts I started being more careful what I used and where I bought them from. Now I only use fittings marked with AN markings and I only use wire with MIL markings.
 
Ray, thats true. In most of the applications we would use it for, its probably fine. There is (fortunately and unfortunately) alot of leeway for the experimental industry, especially in the US. Alot of 'race car parts' on these planes.
Kinda like AN adapters----some are marked and are the real thing, with the 'real' pricing, some are not. Now for full disclosure----we DO make some of ours, and no they are NOT stamped. They have been manufactured to the mil spec drawings, even class 3 threads, but since we dont have a TSO, or a PMA from the FAA ( and not because we havent tried to do so, but waiting 4 years is kinda ridiculous. Thanks COVID. ) we cant stamp them legally. In the certified world they arent accepted without documentation, but for experimentals, its a different story.
So when we set out to begin manufacturing some of our own, Steve and I took the Mil Spec drawings and criteria and made the adapters conform to that.

Tom
 
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