structural stainless steel tank screws needed for PA-32-300

[Dave]

Does anyone have a source and part number for Stainless Steel
structural screws for the fuel tanks on my 1972 Cherokee 6-300?
Spruce, Wag, etc. have them but they are not structural.

[Mike Rapoport]

Spruce has them MS27039

Mike
MU-2


"Dave" > wrote in message
m...
> Does anyone have a source and part number for Stainless Steel
> structural screws for the fuel tanks on my 1972 Cherokee 6-300?
> Spruce, Wag, etc. have them but they are not structural.

[Jay Honeck]

> Does anyone have a source and part number for Stainless Steel
> structural screws for the fuel tanks on my 1972 Cherokee 6-300?
> Spruce, Wag, etc. have them but they are not structural.

If Spruce or Wag Aero are advertising them as stainless steel fuel tank
screws, they are structural.

We replaced ours last year; I think I got 'em through Spruce...
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[JDupre5762]

>Does anyone have a source and part number for Stainless Steel
>structural screws for the fuel tanks on my 1972 Cherokee 6-300?
>Spruce, Wag, etc. have them but they are not structural.

D&D Aircraft Supply of Hampton, NH has kits for the Piper tanks in stainless.
These are definitely structural screws. I have asked them about it before.
Some of the PA 32 series (The retract models) have flush screws in the tanks
and D&D says that they have not found a flush structural screw in stainless of
sufficient strength for that application.

John Dupre'

[Mike Rapoport]

I had a Turbo Lance (PA32RT-300T) and it did not have flush screws.

Mike
MU-2


"JDupre5762" > wrote in message
...
> >Does anyone have a source and part number for Stainless Steel
> >structural screws for the fuel tanks on my 1972 Cherokee 6-300?
> >Spruce, Wag, etc. have them but they are not structural.
>
> D&D Aircraft Supply of Hampton, NH has kits for the Piper tanks in
stainless.
> These are definitely structural screws. I have asked them about it
before.
> Some of the PA 32 series (The retract models) have flush screws in the
tanks
> and D&D says that they have not found a flush structural screw in
stainless of
> sufficient strength for that application.
>
> John Dupre'

[Bret Maverick]

(Dave) wrote in message >...
> Does anyone have a source and part number for Stainless Steel
> structural screws for the fuel tanks on my 1972 Cherokee 6-300?
> Spruce, Wag, etc. have them but they are not structural.

MS27039 are available from gen-aviation-hardware
(http://www.gen-aircraft-hardware.com/) in alloy steel, CRES
(stainless), or beryllium-copper structural.
They are full tension rated structural screws and have a full sized
head.
AN 525 are structural but I think only available in alloy steel. AN
525 are shear screws and are only rated at 50% of the tension load as
MS 27039 screws.
However they have a low profile head and look nicer once installed.
They are available from Spruce and Chief and others I am sure. The
location where they are used is primarily in shear, and the full
tension screws are not necessary. For my money, stainless screws are
subject to galvanic corrosion and can in some instances cause a
problem in this regard. Many pilots in Alaska prefer the steel screws
as they have had problems with the stainless. It is really your call
since the stainless screws do look nicer and if you keep them treated
with LPS or similar they probably won't give you a problem.The steel
screws have the classic gold lacquer finish.

regards,

Bruce Cunningham
N30464

[JDupre5762]

>I had a Turbo Lance (PA32RT-300T) and it did not have flush screws.

I have worked on a PA32R-301T that has flush fuel tank screws.

John Dupre'

[Bruce Cunningham]

(JDupre5762) wrote in message >...
> >I had a Turbo Lance (PA32RT-300T) and it did not have flush screws.
>
> I have worked on a PA32R-301T that has flush fuel tank screws.
>
> John Dupre'

MS 24694 are flush type structural screws and are available in
stainless (MS 24694C). Spruce, Chief, Wicks, and many others have
them.

[JDupre5762]

>MS 24694 are flush type structural screws and are available in
>stainless (MS 24694C). Spruce, Chief, Wicks, and many others have
>them.

That may well be true but when I spoke to D&D supply a couple of years ago they
told me that the stainless flush screws were not strong enough for the
application and they would not sell them in thier Piper fuel tank kits. I
suppose that lots of things can change in two years. I will call them tomorrow
and ask again.

John Dupre'

[[email protected]]

(JDupre5762) wrote in message >...
> >I had a Turbo Lance (PA32RT-300T) and it did not have flush screws.
>
> I have worked on a PA32R-301T that has flush fuel tank screws.
>
> John Dupre'

It also had Piper's version of the tapered (opposed to constant-chord)
wing, hence the PAXXX-XX1X.

Been too long since I worked on a Saratoga (fixed-gear, tapered wing)
to remember whether or not the screws were "flush".

Of course, the 'Toga and the Turbo 'Toga, have since morph'ed into the
6X, and the 6XT, the SP is now a II HP, and the old Turbo SP, is now a
II TC. Same model number, different name, slightly different
airplanes. Personally, I think the "new" little windows and the
overhead switch panel sucks. The cowl looks kewl tho.

The Lance is history.

If you're confused, walk into your Gulfstream dealer and ask to see a
new G-IVSP or a G-V.

I truly love thread drift, sorry.

If you wanna me to get semi-back on-topic, I've allegedly installed
quite a few MS27039C (heavy emphasis on the C) screws (available at an
aerospace hardware-peddler near YOU) through PAXX fuel tanks. Unless
you can show me a piece of oh-fee-shul Piper paperwork with a FAA
facsimile sig, technically it's contrary to the CAR/FAR/CFR, without
specific approved/acceptable supplementary documentation. I guess
that means I might be spending eternity in mechanic's purgatory.

TC

P.S. I also think it's pretty neat that the Seneca V still has
injected TCM engines, but does not have TCM fuel injection. Had to
explain to a TCM engine rep years ago that you have to start a V like
it had a Lycoming under the cowl.

[Bruce Cunningham]

(JDupre5762) wrote in message >...
> >MS 24694 are flush type structural screws and are available in
> >stainless (MS 24694C). Spruce, Chief, Wicks, and many others have
> >them.
>
> That may well be true but when I spoke to D&D supply a couple of years ago they
> told me that the stainless flush screws were not strong enough for the
> application and they would not sell them in thier Piper fuel tank kits. I
> suppose that lots of things can change in two years. I will call them tomorrow
> and ask again.
>
> John Dupre'

John,
MS 24694C screws are 300 series stainless with an ultimate strength of
85,000 psi. Typical non-structural machine screws have tensile
strengths of 55-60,000 psi. Most steel structural screws (MS 27039, AN
525, MS 24694) have tensile strengths of 125,000 psi. The MS 24694C
are classified as structural since they have an unthreaded shank
portion where any shear load is carried. This unthreaded portion is
critical to any structural screw as having threads in shear is a BIG
no-no. If you need to have stronger screws that 85 ksi., then they are
made but I don't know who sells them. The 85 ksi screws are stronger
than the 2024-T3 aluminum they are mounted in for any thickness up to
..120 in. for the thinnest flange that the tanks or wing section may
have (not the total thickness, for a #10 size screw which is I think
the size used in the tanks). If you want to look for them, either NAS
1221E or NAS 8703 are 160,000 psi corrosion resistant alloy, flush
structural screws. Gen aircraft hardware does not sell them, but if
you call them they may know who does.

[JDupre5762]

(JDupre5762) wrote in message
>...
>> >MS 24694 are flush type structural screws and are available in
>> >stainless (MS 24694C). Spruce, Chief, Wicks, and many others have
>> >them.
>>
>> That may well be true but when I spoke to D&D supply a couple of years ago
>they
>> told me that the stainless flush screws were not strong enough for the
>> application and they would not sell them in thier Piper fuel tank kits. I
>> suppose that lots of things can change in two years. I will call them
>tomorrow
>> and ask again.
>>
>> John Dupre'
>
>John,
>MS 24694C screws are 300 series stainless with an ultimate strength of
>85,000 psi. Typical non-structural machine screws have tensile
>strengths of 55-60,000 psi. Most steel structural screws (MS 27039, AN
>525, MS 24694) have tensile strengths of 125,000 psi. The MS 24694C
>are classified as structural since they have an unthreaded shank
>portion where any shear load is carried. This unthreaded portion is
>critical to any structural screw as having threads in shear is a BIG
>no-no. If you need to have stronger screws that 85 ksi., then they are
>made but I don't know who sells them. The 85 ksi screws are stronger
>than the 2024-T3 aluminum they are mounted in for any thickness up to
>.120 in. for the thinnest flange that the tanks or wing section may
>have (not the total thickness, for a #10 size screw which is I think
>the size used in the tanks). If you want to look for them, either NAS
>1221E or NAS 8703 are 160,000 psi corrosion resistant alloy, flush
>structural screws. Gen aircraft hardware does not sell them, but if
>you call them they may know who does.
>

I spoke to D&D Aircraft Supply today. What they told me is that they try to
guarrantee that their stainless screws have the same or better strength as the
original cadmium plated steel structural screws. As stated above the type of
stainless steel used in MS 24694 screws leaves the screw actually weaker than
the original cadmium plated variety. D&D says that the stainless variety may
well be strong enough and Piper might admit that but D&D's decision is to
market replacement stainless kits that are known to be a direct replacement for
the original cad plated steel hardware as specified by Piper, or Cessna etc.

John Dupre'