Learning from an owner annual

Private wrote:
"Jim Macklin" wrote in message
news:EZF9g.20244$ZW3.18025@dukeread04...
I've heard of owners replacing the standard fasteners with
nice shiny stainless steel screws. Trouble is you can get
dissimilar metal galvanic reactions and then you have to
drill them out.


I am aware of galvanic corrosion, which often corrodes aluminum when it is
in contact with steel, especially if in the presence of moisture and even
more especially moisture with salt. The use of stainless fasteners should
AFAIK greatly reduce corrosion of the fasteners but am unaware of any change
to the galvanic corrosion rates on the aluminum. Are you suggesting an
increase in galvanic action between a stainless fastener and a plain steel
nut? Please expand.

What I have heard is this. If you use a carbon steel screw in the
aluminum structure, the corrosion occurs on the steel screw (rusted
screws). To correct the problem, you just replace the screws. If you
use stainless screws, this changes the galvanic status of the
connection to where the aluminum becomes the metal that corrodes. This
means that if you allow corrosion to occur, the aluminum structure
around the screw is what corrodes instead of the screw. To correct this
situation, you have the aluminum structure around the screw to replace,
which is much more involved and expensive than just replacing the
screws.

I would also appreciate comment on the use of thread lubricants like
'Nevr-Seize' which IMHO allow increased clamping force and also greatly
reduce thread seizing from corrosion.

Use of a good corrosion preventative like corrosion X or ACF-50 should
prevent any corrosion of the structure, if you keep it applied every
annual.

I find never-seize on threads to work magic minimizing corrosion, but
one has to be very careful not to get it on the phillips head or the
phillips driver. Even traces of it (or paint) make the drivers cam
out. Buy lots of spare screws and drive bits. Use solvent on the
drivers and the screw heads.

It doesn't help that those damn AN structural screws (can't remember
the number) are so soft and the phillips socket so shallow that the
heads strip out much easier than those unapproved pan head stainless
fasteners. I don't know what they offer except of course a full
diameter shank and a lot of ductility.

Some of you must live in a very corrosive environment though.

"Private" wrote in message
news:yu2ag.165036$7a.147100@pd7tw1no...

"Jim Macklin" wrote in message
news:EZF9g.20244$ZW3.18025@dukeread04...
I've heard of owners replacing the standard fasteners with
nice shiny stainless steel screws. Trouble is you can get
dissimilar metal galvanic reactions and then you have to
drill them out.


I am aware of galvanic corrosion, which often corrodes aluminum when it is
in contact with steel, especially if in the presence of moisture and even
more especially moisture with salt. The use of stainless fasteners should
AFAIK greatly reduce corrosion of the fasteners but am unaware of any
change to the galvanic corrosion rates on the aluminum. Are you
suggesting an increase in galvanic action between a stainless fastener and
a plain steel nut? Please expand.

I would also appreciate comment on the use of thread lubricants like
'Nevr-Seize' which IMHO allow increased clamping force and also greatly
reduce thread seizing from corrosion.

All it takes for corrosion to begin is two dissimilar metals and a bit of
dirty moisture (obtainable free from polution and humidity). Even two
pieces aluminum of different alloys can cause corrosion. AC43-13, which
every owner should have a copy of, has an excellent section on corrosion.

On 14 May 2006 03:37:06 -0700, "Jay Honeck"
wrote:


This seems odd, Robert. Is your plane parked outside? Why would those
inspection panel screws be so corroded? Unless...were they never
removed recently? (More work undone-but-paid-for?)

I strip a fair number of screws every year -- but I've NEVER had to
drill any out on either of the planes we've owned.

Dude, you really need to take a good look at the underside of a
Mooney, especially an older one. You just "think" a PA28 has a lot of
screws. Unless things have changed a whole bunch, they are mostly
countersunk machine screws, opposed to your universal head PK screws.

Really ups the temptation for a tech/owner to use power tools to crank
the **** out them when closing up. Makes me shudder just thinking
about it..

What I like is when you have everything in neat little tupperware cups
underneath the appropriate parts of the plane -- and then the shop
moves the plane. Or they pull an extension cord under your plane, and
lasso all the parts buckets. Or they get kicked over. THAT is my pet
peeve about doing an annual.

Mine is wheels off for inspection, somebody steps on the pedals and
blows out the wheel cylinder pistons.

I would highly recommend this experience to any aircraft owner who is
comfortable with a wrench.

Agree 100%. I have a voluminous knowledge of the inner workings of my
aircraft, solely because of doing the owner-assisted annuals.

In my case, the transition from allegedly mucho-experienced tech to
private pilot was definitely made a lot easier by having in-depth
knowledge of aircraft systems.

TC

wrote:

Dude, you really need to take a good look at the underside of a
Mooney, especially an older one. You just "think" a PA28 has a lot of
screws. Unless things have changed a whole bunch, they are mostly
countersunk machine screws, opposed to your universal head PK screws.

Really ups the temptation for a tech/owner to use power tools to crank
the **** out them when closing up. Makes me shudder just thinking
about it..


I have no problem using power tools to do that, you just need to use the
right ones and use them the right way. Every quality power screwdriver
I have ever used has an adjustable torque limiter, this will make sure
they don't get put in too tight.


--
Chris W
KE5GIX

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give the gifts they want
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You know what? I've been through this one so many times, but it's been
a few years, and I just don't have the energy to fight this fight
again.

There is NO "torque-limiting" power screwdriver-type tool that has both
the ability to prevent over-tightening, and allow sufficient "torque"
to be applied to screws installed into aircraft nutplates.

A slightly boogered screw or nutplate will NOT be tightened
sufficiently, or else other screws will be over-tightened-there is NO
middle ground.

In most cases, a quality torque-limiting screwdriver set at minimal
torque can be used by an experienced operator to run screws and
initially secure panels. The final "ginch" needs to be performed by a
human that knows what the **** he/she is doing.

There is a large portion of the "certified technician" population that
isn't smart enuff to use the proper bit for the type of screw to be
r/r'd, let alone to use power to drive it. It's not much of a stretch
to say that this applies to owner-performed maintenance also.

TC

Yes and bits are cheap, use new Phillips bits regularly.
Once the screwdriver is damaged it will destroy all the
screw slots afterward.

If the screws have paint in the slot, clean it out before
you try to unscrew the fastener.

--
James H. Macklin
ATP,CFI,A&P

--
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But government sees it as an obstacle to be overcome.
some support
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See http://www.fija.org/ more about your rights and duties.



wrote in message
oups.com...
| You know what? I've been through this one so many times,
but it's been
| a few years, and I just don't have the energy to fight
this fight
| again.
|
| There is NO "torque-limiting" power screwdriver-type tool
that has both
| the ability to prevent over-tightening, and allow
sufficient "torque"
| to be applied to screws installed into aircraft nutplates.
|
| A slightly boogered screw or nutplate will NOT be
tightened
| sufficiently, or else other screws will be
over-tightened-there is NO
| middle ground.
|
| In most cases, a quality torque-limiting screwdriver set
at minimal
| torque can be used by an experienced operator to run
screws and
| initially secure panels. The final "ginch" needs to be
performed by a
| human that knows what the **** he/she is doing.
|
| There is a large portion of the "certified technician"
population that
| isn't smart enuff to use the proper bit for the type of
screw to be
| r/r'd, let alone to use power to drive it. It's not much
of a stretch
| to say that this applies to owner-performed maintenance
also.
|
| TC
|

wrote in message
oups.com...
You know what? I've been through this one so many times, but it's been
a few years, and I just don't have the energy to fight this fight
again.

There is NO "torque-limiting" power screwdriver-type tool that has both
the ability to prevent over-tightening, and allow sufficient "torque"
to be applied to screws installed into aircraft nutplates.




But... a power screwdriver set below the specified torque for a screw and
then torqued by hand with a calibrated torque wrench set to the proper
setting will work just fine, or am I wrong?

I believe that I am restating your paragraph below, but in a way that my son
or mother could read it.





A slightly boogered screw or nutplate will NOT be tightened
sufficiently, or else other screws will be over-tightened-there is NO
middle ground.



We were taught in A&P school not to reuse fasteners. I doubt very seriously
that this actually happens in the real world, but in the schools perfect
world, this should eleminate *most* of the "boogered" fastener problems.





In most cases, a quality torque-limiting screwdriver set at minimal
torque can be used by an experienced operator to run screws and
initially secure panels. The final "ginch" needs to be performed by a
human that knows what the **** he/she is doing.

There is a large portion of the "certified technician" population that
isn't smart enuff to use the proper bit for the type of screw to be
r/r'd, let alone to use power to drive it. It's not much of a stretch
to say that this applies to owner-performed maintenance also.

TC





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wrote:
You know what? I've been through this one so many times, but it's been
a few years, and I just don't have the energy to fight this fight
again.

There is NO "torque-limiting" power screwdriver-type tool that has both
the ability to prevent over-tightening, and allow sufficient "torque"
to be applied to screws installed into aircraft nutplates.

I guess I should have been more clear. I didn't intend to use the
screwdriver to set the screws to the proper torque, I never trust those
kind of tools for that, just to get it in with out getting them too
tight. On any thing that is important, I always go back over it with a
hand driver to finish the job and get them tight. Also why would anyone
reuse a screw with messed up threads? Just get a new one already. The
nut plate is another story though, those are a bit of work to replace so
I guess it would depend on just how bad the threads were.

--
Chris W
KE5GIX

Gift Giving Made Easy
Get the gifts you want &
give the gifts they want
One stop wish list for any gift,
from anywhere, for any occasion!
http://thewishzone.com

I used a torque limiting powered screwdriver once on the PK screws into
tinnermans to put my Cessna back together. I learned a lessons after a
flight when several were missing. I use the power screwdriver to run the
screws in and the torque by hand. No problems since.

Ross

wrote:

You know what? I've been through this one so many times, but it's been
a few years, and I just don't have the energy to fight this fight
again.

There is NO "torque-limiting" power screwdriver-type tool that has both
the ability to prevent over-tightening, and allow sufficient "torque"
to be applied to screws installed into aircraft nutplates.

A slightly boogered screw or nutplate will NOT be tightened
sufficiently, or else other screws will be over-tightened-there is NO
middle ground.

In most cases, a quality torque-limiting screwdriver set at minimal
torque can be used by an experienced operator to run screws and
initially secure panels. The final "ginch" needs to be performed by a
human that knows what the **** he/she is doing.

There is a large portion of the "certified technician" population that
isn't smart enuff to use the proper bit for the type of screw to be
r/r'd, let alone to use power to drive it. It's not much of a stretch
to say that this applies to owner-performed maintenance also.

TC