Opinions Please

RVG8tor · #1 01-06-2009, 04:54 PM

I have just completed painting my interior a dark grey. I want to use stainless 6 lobe screws to fasten the various panels and consoles. You can see how nice they look with the shot of my throttle console.

I have read VAF discussions about the difference with the strength of aviation grade screws and the non-aviaton type. I was going to use stainless on my QB fuel tanks. But with interior panels am I correct that the strength is not really an issue (not much load)? Also can someone tell me if there might be more potential for corrosion with this setup. All of my floors and consoles are primed on the back and painted on the outside. If you have used stainless screws and have some experience good or bad that would be appreciated.

Thanks for any advice

mannanj · #2 01-06-2009, 05:41 PM

Opinions Please???? As the Brits say, are you daft?

I'll bet you get everything from "they're the best thing since sliced bread" to----- "Your airplane will fall out of the sky"

Seriously though, I used them on my wing tanks and wing/empenage tips.

If you look at your photo; you see that the cap that covers the formers that transfer the load from the wing carry through spar up through the rest of the aircraft is attached with pop rivets.

Surely, stainless steel screws will safely do the job. I'm not a Structural Engineer though so don't take this as Gospel.

Geico266 · #3 01-06-2009, 05:56 PM

Quote:

Originally Posted by RVG8tor

I have just completed painting my interior a dark grey. I want to use stainless 6 lobe screws to fasten the various panels and consoles. You can see how nice they look with the shot of my throttle console.

I have read VAF discussions about the difference with the strength of aviation grade screws and the non-aviaton type. I was going to use stainless on my QB fuel tanks. But with interior panels am I correct that the strength is not really an issue (not much load)? Also can someone tell me if there might be more potential for corrosion with this setup. All of my floors and consoles are primed on the back and painted on the outside. If you have used stainless screws and have some experience good or bad that would be appreciated.

Thanks for any advice

Looks good, but why wouldn't you use AN stainless steel screws?

http://www.aircraftspruce.com/catalog/hapages/an526.php scroll down about 1/2 the page. I like the truss head screws for interior stuff, but to each his own.

roee · #4 01-06-2009, 06:39 PM

Quote:

Originally Posted by RVG8tor

I have read VAF discussions about the difference with the strength of aviation grade screws and the non-aviaton type.

"Aviation grade" hardware (i.e. AN, MS, NAS, etc.) is not necessarily stronger than "non-aviation". But the aviation hardware is designed and manufactured to meet standard specifications (i.e. AN...), while non-aviation hardware is not. So the difference is when you buy the AN hardware specified by the airframe designer, you know what you're getting, and you know that it'll meet the airframe designer's requirements that it was selected for. Whereas with non-aviation hardware, you really don't know what you're getting, and you don't know whether or not it'll meet the airframe designer's requirements.

Quote:

Originally Posted by Geico266

Looks good, but why wouldn't you use AN stainless steel screws?

Remember that even AN stainless steel screws are not the same as AN cadmium-plated carbon steel screws. They are not as strong. Different materials have different properties, and the AN specs reflect that. For example, you can't always arbitrarily substitute a AN526C for an AN526.

All that said...

Quote:

Originally Posted by RVG8tor

But with interior panels am I correct that the strength is not really an issue (not much load)?

For cover panels that are you are sure are not significantly stressed and are not structurally important, you should be fine no matter what hardware you use (i.e. you won't fall out of the sky). For anything that is stressed, or is structurally important (like the tank skins), you'd be wise to stick to the exact hardware specified in the plans.

GAHco · #5 01-07-2009, 09:32 AM

See this previous post

http://www.vansairforce.com/communit...ss+tank+screws

It might surprise you who started the thread!

Best wishes.

RVG8tor · #6 01-07-2009, 03:03 PM

Tom,

I knew I started that thread, it was focused on the tank screws and it was enough to make me not use the SS screws there. I was not sure what folks thought about using them on interior panels and if there was a higher corrosion potential. After reading you post on the last thread I assume there is a slight potential but if they are on the interior and the plane kept in a hanger is the potential significant? My thought is that it was not significant enough not to use them.

Cheers

GAHco · #7 01-07-2009, 11:15 PM

Quote:

Originally Posted by RVG8tor

Tom,

I knew I started that thread, it was focused on the tank screws and it was enough to make me not use the SS screws there. I was not sure what folks thought about using them on interior panels and if there was a higher corrosion potential. After reading you post on the last thread I assume there is a slight potential but if they are on the interior and the plane kept in a hanger is the potential significant? My thought is that it was not significant enough not to use them.

Cheers

Mike,

PM me your address, I will send you a sample of #6 nylon washers.
Push em on for a tight fit on # 8 screws (wont loose em later) or a regular fit
for #6 screws.

The corrosion potential is higher wherever the stainless comes in direct contact with the aluminum (use the washers)

For what you are doing the AN526C series (truss head) will work well and have a comfortable head that will not snag as much as the taller pan head screws.

If you do like pan head (steel) I always recommend the NAS601,602 etc, they are 2&1/2 times stronger than the an515 ms35206 series and wont snap off in your nutplates.

frankh · #8 01-08-2009, 08:43 AM

On the shear strength of the SS 6 lobe screws to hold the fuel tank skins, before I used them.

I don't have the data handy but even with full tanks at 9G it still wasn't a problem.

I'm prettyr sure I concluded the edges of the tank skins would rip off before the screws failed.

As I have +5 and -2.3G posted on my G meter I thought I had better report that I hadn't actually fallen out of the sky...

The big advantage of these screws (apart from the fact they look nice) is that they will never strip unlike AN hardware..You can put all your inspection plates on with a battery drill and make the final fit a lot less exhausting and much quicker.

Frank