non-AN hardware for engine
 

My narrow deck O320-B2B requires non-AN hardware for several things I am working on. I need (4) 5/16-18 x 1.25" hex head bolts - Lane Aviation wants $28 each for them! I need one 5/16-18 x .75, it is $3. 1/4-20 nuts (STD-1411)? Nada. 1/4-20 x 1.50" (STD-1414)? Nada.

What does one do for finding this kind of hardware? I tried http://www.gen-aircraft-hardware.com and Aircraft Spruce but couldn't find what I was looking for.

Thanks! Phil

Grade 8 hardware? :)

ETA...looks like ACS carries the nuts, listed as Exhaust Manifold Nuts

http://www.aircraftspruce.com/catalo...nifoldnuts.php

But still...two and a half bucks for a NUT? C'mon...

Have you tried NAPA? They had some studs that I needed and were quite a bit less expensive that the normal Lycoming parts distributors. Just don't tell them what engine you're planning on installing the bolts you're looking to find.

bob

The hardware that Lycoming uses is actually grade 5. Grade 8 is more than adequate. AN hardware can be used as well. Tractor Supply sells grade 8 by the pound, so thats where I go for coarse-thread hardware.

Phil,

www.mcmaster.com
p/n 99894A209

John.

You guys rock, of course. Is it safe to say that if I can't find something I need in the AN spec hardware, or it is crazy expensive like a $28 5/16-18 x 1.25 bolt, that I can use Grade 5 hardware? Thanks again! Phil

McMaster.com (Search for Mil Spec bolts.) I just had the same issue getting bolts for my O235C1B.

beware of counterfits
 

There is lots of folklore about poor quality fasteners shipped from overseas that are marked as grade 5 or grade 8. I don't really know whether to worry about it or not. I have never had a problem, never found a soft bolt at my local hardware store. But I think it does warrent just a bit of scrutiny -- a place like NAPA is probably pretty safe to have real qualiy stuff.

Probably okay, but you'd never know because you have no pedigree on the fasteners. I don't know if it's even a concern for these applications, although it might well be.

Even if you *have* the paperwork, that's still no guarantee...there was quite recently a giant mess (and federal criminal charges levied) with titanium from a certain company, where the data was out-and-out faked, and the material was found to fail at less than half the specified values for stress. Caused all sorts of grief and analysis and rework on our vehicles.

Probably the best you could do is, as noted here, buy from reputable outfits and keep your ear to the ground for info about bogus parts, and then keep a watchful eye during inspections for failed fasteners.

I needed an odd length for my case mount alternator bracket, and most of the local sources like Tractor Supply and Ace only carried 1/2" length increments. We are fortunate to have a local fastener specialist who had 1/4" length increments in stock. You might look in the phone book or google maps to see if you have a similar source available.