R

ron sterba

Well Known Member
On my QB9a I am installing the fuel tank access plates and was told to use a TORX head equivalent. Anybody know where I can buy these. I don't know the NAME of them so I wasn't able to find them at Aircraft Spruce or American aircraft hardware thru pictures. The reason I have been told is if there was ever a reason to remove the plate the TORX are a lot easier to unscrew.

Ron in Oregon
 
Keep in mind stainless steel fasteners are not structural fasteners (unless they carry an MS number), they have a lower tensile strength than steel (I hate them because they strip much easier) and present a galvanic corrosion issue when used in alumimum structures.

Using "hardware" variety fasteners from unknown sources as substitutes for aircraft AN hardware is not recommended.

My advise, stick with cad plated AN fasteners.
 
What do you think of this?

http://www.aircraftspruce.com/catalog/hapages/nas1801.php

Cad-plated, with a 1/4" (I think) hex bolt head in addition to a Phillips slot.

I'm at this stage too, but I've talked to builders who used the AN515s, even encapsulated in sealant, yet had little difficulty removing them when cured after cleaning out the Phillips slot, using a good screwdriver bit, and perhaps some valve grinding compound to help with the grip. So I'm wondering if it's really necessary to use different hardware here. Servicing without removing the tank from the wing might be more of a motivation, but I even wonder how useful that is.
 
You might find these easier to use. An allen key will fit in the small space above the screws and should not slip...

http://www.aircraftspruce.com/catalog/hapages/NAS1351.php

NAS1351.jpg
 
I put standard round head #8 screws on my tank access plates when I built them, them later opened them up again to add a return line. I had no difficulty at all getting my screw-gun to bite the screws and remove them (with the tanks on the wing, wings NOT on the airplane), and I went back on with more #8 round heads - but I do believe I'm going to open them up again and put Allen-head screws in before I mate the wings to the fuse for the last time.
 
Thanks Guys, Going with cad cap screws on the Tank access plate just in case I ever have to pull the senders out. Great idea Gil. Walt, and Greg, Shannon and Greg, always appreciate other builders ideas. Thanks Guys.
Ron in Oregon
 
Sounds like an excellent choice. Do you think washers will be needed as well due to the smaller head?
 
I got mine...

in the aviation section of Home Depot. Cheaper than Aircraft Spruce and I didn't have to wait for them to come via UPS
 
smiller said:
What do you think of this?

http://www.aircraftspruce.com/catalog/hapages/nas1801.php

Cad-plated, with a 1/4" (I think) hex bolt head in addition to a Phillips slot.

.
Click to expand...

I like this idea a lot. My only concern is that there is an unthreaded portion of the shank just under the hex head on these. Whereas the AN515-8R8's have threads right up to the heads. See picture below). I wonder if one or two washers would be required which then means you need to get slightly longer shanks.



Also the shank seems to expand as it approaches the head..could this deform the access plate?

Did you try these? How do they work?

thanks!
 
Saville said:
I like this idea a lot. My only concern is that there is an unthreaded portion of the shank just under the hex head on these. Whereas the AN515-8R8's have threads right up to the heads. See picture below). I wonder if one or two washers would be required which then means you need to get slightly longer shanks.



Also the shank seems to expand as it approaches the head..could this deform the access plate?

Did you try these? How do they work?

thanks!
Click to expand...

That unthreaded bit should only be 1/16 inch max. according to the specifications -

http://www.gen-aircraft-hardware.com/images/pdf/nas1801_2.pdf

Since a washer should be .032 or more and with the thickness of the plate it should have no effect.

I've started using these for some of the #8 screws in the cockpit area, high strength and you can use either a Philips screwdriver or a 1/4 inch hex socket.
 
az_gila said:
That unthreaded bit should only be 1/16 inch max. according to the specifications -

http://www.gen-aircraft-hardware.com/images/pdf/nas1801_2.pdf

Since a washer should be .032 or more and with the thickness of the plate it should have no effect.

I've started using these for some of the #8 screws in the cockpit area, high strength and you can use either a Philips screwdriver or a 1/4 inch hex socket.
Click to expand...

You could use 2 or more washers.
 
Saville said:
I like this idea a lot. My only concern is that there is an unthreaded portion of the shank just under the hex head on these. Whereas the AN515-8R8's have threads right up to the heads. See picture below). I wonder if one or two washers would be required which then means you need to get slightly longer shanks.



Also the shank seems to expand as it approaches the head..could this deform the access plate?

Did you try these? How do they work?

thanks!
Click to expand...

I found these at Spruce during construction years ago. I think they are wonderful. I used them (generally with washers) everywhere that I thought access with a screwdriver was going to be a PITA. Examples are the seat pans next to the fuselage sides. The rear baggage bulkhead is a breeze with these. Used them a lot in the footwell and behind the panel too. Elsewhere just the standard screws supplied by Vans.

Never had any issue with the non threaded section because the nutplates are not threaded to the top either. They have a little conical lead in from the stamping process.

I agree with Walt 100% in regards to stainless choices.
 
Last edited:
rzbill said:
Never had any issue with the non threaded section because the nutplates are not threaded to the top either. They have a little conical lead in from the stamping process.

I agree with Walt 100% in regards to stainless choices.
Click to expand...

The conical section will be striking the access plate. Unless the access plate is a little dimpled, the access plate will either be deformed, or all the clamping force will be concentrated at some point on the cone. One way or another, I'd be worried that the hole at the conical section will eventually open up with stress/vibration and therefore loosen the clamping pressure - I would think.

Maybe I'm wrong.

Never intended to use stainless.
 
No problem

Saville said:
The conical section will be striking the access plate. Unless the access plate is a little dimpled, the access plate will either be deformed, or all the clamping force will be concentrated at some point on the cone. One way or another, I'd be worried that the hole at the conical section will eventually open up with stress/vibration and therefore loosen the clamping pressure - I would think.

Maybe I'm wrong.

Never intended to use stainless.
Click to expand...

It should not be a problem.

I just checked all of my NAS1802 #8 screws and they all fit nicely all the way into the #19 hole on my drill gauge - I even used the reverse side of the gauge without the chamfer.

I think the look of that "shoulder" may be deceiving in the picture and there certainly would be no hang up/interference, especially if a thin washer is used under the head.
 
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