Author: Clifford Dow <cdowjr@...> Time: Thu Dec 20, 2001 9:06 am PST Link
FYI
Just received the below message from Gus at Vans
aircraft on this topic.
"For all practical purposes the rivets will be as
strong whichever way
they go in. Generally convention says the manufactured
head goes
up or forward. However, it is also usually easier to
set the rivet
properly if the manufactured head is on the thin piece
of metal if
there is a substantial difference in thickness between
the two. So
in this case we would say the best way is with the
manufactured
head forward on the thin spar material.
Gus
I'd like to actually do a test, but I wonder how you
would do it. You might take a thick piece of metal
and rivet it to a thin piece and then rig up a system
to hang concrete blocks from the thin piece until the
rivet gave way - but I wonder how you might grab onto
the thin piece for pulling - without the thin piece
getting twisted all up.
I'll work on getting a proper engineering answer from
perhaps a Boeing engineer. Again the question is
which is stronger when attaching a thin and thick
piece of metal together - a rivet where the mashed end
is against the thin metal or thick metal? I say the
thick metal as is confirmed by Vans.
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Author: robert_riggen@... Time: Thu Dec 20, 2001 9:14 am PST Link
I believe that the thin metal would fail in your test long before either
head of the rivet did!
Thanks,
Rob
Robert Riggen
N296VT (reserved)
RV7 - Tail assy
Clifford Dow
<cdowjr@yahoo To: RV-7A YAHOO GROUP <RV7and7A@yahoogroups.com>
.com> cc:
Subject: [RV7and7A] Rivet Direction - in or out - on
12/20/2001 Vertical Stabilizer
12:06 PM
Please
respond to
RV7and7A
FYI
Just received the below message from Gus at Vans
aircraft on this topic.
"For all practical purposes the rivets will be as
strong whichever way
they go in. Generally convention says the manufactured
head goes
up or forward. However, it is also usually easier to
set the rivet
properly if the manufactured head is on the thin piece
of metal if
there is a substantial difference in thickness between
the two. So
in this case we would say the best way is with the
manufactured
head forward on the thin spar material.
Gus
I'd like to actually do a test, but I wonder how you
would do it. You might take a thick piece of metal
and rivet it to a thin piece and then rig up a system
to hang concrete blocks from the thin piece until the
rivet gave way - but I wonder how you might grab onto
the thin piece for pulling - without the thin piece
getting twisted all up.
I'll work on getting a proper engineering answer from
perhaps a Boeing engineer. Again the question is
which is stronger when attaching a thin and thick
piece of metal together - a rivet where the mashed end
is against the thin metal or thick metal? I say the
thick metal as is confirmed by Vans.
__________________________________________________
Do You Yahoo!?
Check out Yahoo! Shopping and Yahoo! Auctions for all of
your unique holiday gifts! Buy at http://shopping.yahoo.com
or bid at http://auctions.yahoo.com
Van's Air Force - World Wide Wing
www.vansaircraft.net
Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Author: Clifford Dow <cdowjr@...> Time: Thu Dec 20, 2001 9:22 am PST Link
Rob:
Ha but that's not the question.
The question is would the failure occur sooner with
the mashed head against the thin metal or the thick
metal?
My friend who worked for Boeing for 8 years insists
the structure would be stronger if the mashed end were
on the thin side. I'd like to understand why - if in
fact he is right.
It seems to me the thin metal might tear sooner if it
had the mashed end of the rivet on the thin side.
Kind of a topic not worth all this discussion, but it
seems there must be one way which is better.
cliff dow jr
cdowjr@y...
--- robert_riggen@i... wrote:
>
> I believe that the thin metal would fail in your
> test long before either
> head of the rivet did!
> Thanks,
>
> Rob
>
> Robert Riggen
> N296VT (reserved)
> RV7 - Tail assy
> Clifford Dow
> <cdowjr@yahoo To:
> RV-7A YAHOO GROUP <RV7and7A@yahoogroups.com>
>
> .com> cc:
> Subject:
> [RV7and7A] Rivet Direction - in or out - on
>
> 12/20/2001 Vertical
> Stabilizer
>
> 12:06 PM
> Please
> respond to
> RV7and7A
> FYI
> Just received the below message from Gus at Vans
> aircraft on this topic.
>
> "For all practical purposes the rivets will be as
> strong whichever way
> they go in. Generally convention says the
> manufactured
> head goes
> up or forward. However, it is also usually easier to
> set the rivet
> properly if the manufactured head is on the thin
> piece
> of metal if
> there is a substantial difference in thickness
> between
> the two. So
> in this case we would say the best way is with the
> manufactured
> head forward on the thin spar material.
> Gus
> I'd like to actually do a test, but I wonder how you
> would do it. You might take a thick piece of metal
> and rivet it to a thin piece and then rig up a
> system
> to hang concrete blocks from the thin piece until
> the
> rivet gave way - but I wonder how you might grab
> onto
> the thin piece for pulling - without the thin piece
> getting twisted all up.
> I'll work on getting a proper engineering answer
> from
> perhaps a Boeing engineer. Again the question is
> which is stronger when attaching a thin and thick
> piece of metal together - a rivet where the mashed
> end
> is against the thin metal or thick metal? I say the
> thick metal as is confirmed by Vans.
> __________________________________________________
> Do You Yahoo!?
> Check out Yahoo! Shopping and Yahoo! Auctions for
> all of
> your unique holiday gifts! Buy at
> http://shopping.yahoo.com
> or bid at http://auctions.yahoo.com
> Van's Air Force - World Wide Wing
> www.vansaircraft.net
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
__________________________________________________
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Check out Yahoo! Shopping and Yahoo! Auctions for all of
your unique holiday gifts! Buy at http://shopping.yahoo.com
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Author: "ualguy51" <jag060571@...> Time: Thu Dec 20, 2001 4:39 pm PST Link
-Cliff:
I'm going to have to agree with Rob and Gus on this one. I've also
been in industry for about 8 years much like your friend who worked
for Boeing. I work for an Airline serving as both an overhaul
Mechanic and now as an Engineer. I'm not bragging, as it's not a
great time to be in industry I can assure you. However, my point is
this; Gus gave you the classic textbook answer on how and why the
rivets are place like they are. He is absolutely correct. Rob also
answered your question. If I understand you correctly you want to
know if the ultimate tensile strength (force applied in tension
causing material failure) of the bucked end of the rivet is greater
than the ultimate shear strength (force applied in shear causing
material failure) of the thinner metal?
There are a few areas to consider when looking at this. Is the
bucked end of the rivet bucked properly? If memory serves me
correctly it should be 1.5 times the diameter of the rivet shank.
Also, you must realize the bucked end is now cold worked and harder
than its manufactured end.
The other item to consider is the edge distance from the edge of the
rivet in question to the edge of the material.
If you take the vertical Stab for example you will see mostly shear
loads on the fasteners. Therefore, the thinner material will exceed
its designed ultimate shear strength before either head of the rivet
lets go. This can be verified with the MIL-SPEC (military
specifications) handbook that your friend can get from Boeing. Also,
you can rivet together a test sample and put one end in a vise and a
pair of vice-grips hooked to a large fish scale on the other end.
(crude but affective) To ensure accuracy, the vice and vice-grip
should have an equal grip on the test material. This will not only
show you what you want to know but it will show you somewhat
accurately what amount of force it took for the thinner metal to
fail. Remember, if you use 3 rivets, divide your force by 3 and if
you use 2 rivets you would of course divide by 2. Etc.
Your question is VERY valid and is a major area of concern in the
industry. These things have to be analyzed daily when meatheads
drive catering trucks or baggage loaders into the side of an
airplane. Engineers go right for the MIL-SPEC handbook for this
information because all aircraft material including rivets has been
tested.
I hope this answers your question.
Ken
--- In RV7and7A@y..., Clifford Dow <cdowjr@y...> wrote:
> Rob:
> Ha but that's not the question.
> The question is would the failure occur sooner with
> the mashed head against the thin metal or the thick
> metal?
> My friend who worked for Boeing for 8 years insists
> the structure would be stronger if the mashed end were
> on the thin side. I'd like to understand why - if in
> fact he is right.
> It seems to me the thin metal might tear sooner if it
> had the mashed end of the rivet on the thin side.
> Kind of a topic not worth all this discussion, but it
> seems there must be one way which is better.
> cliff dow jr
> cdowjr@y...
> --- robert_riggen@i... wrote:
> >
> > I believe that the thin metal would fail in your
> > test long before either
> > head of the rivet did!
> > Thanks,
> >
> > Rob
> >
> > Robert Riggen
> > N296VT (reserved)
> > RV7 - Tail assy
> > Clifford Dow
> > <cdowjr@yahoo To:
> > RV-7A YAHOO GROUP <RV7and7A@y...>
> >
> > .com> cc:
> > Subject:
> > [RV7and7A] Rivet Direction - in or out - on
> >
> > 12/20/2001 Vertical
> > Stabilizer
> >
> > 12:06 PM
> > Please
> > respond to
> > RV7and7A
> > FYI
> > Just received the below message from Gus at Vans
> > aircraft on this topic.
> >
> > "For all practical purposes the rivets will be as
> > strong whichever way
> > they go in. Generally convention says the
> > manufactured
> > head goes
> > up or forward. However, it is also usually easier to
> > set the rivet
> > properly if the manufactured head is on the thin
> > piece
> > of metal if
> > there is a substantial difference in thickness
> > between
> > the two. So
> > in this case we would say the best way is with the
> > manufactured
> > head forward on the thin spar material.
> > Gus
> > I'd like to actually do a test, but I wonder how you
> > would do it. You might take a thick piece of metal
> > and rivet it to a thin piece and then rig up a
> > system
> > to hang concrete blocks from the thin piece until
> > the
> > rivet gave way - but I wonder how you might grab
> > onto
> > the thin piece for pulling - without the thin piece
> > getting twisted all up.
> > I'll work on getting a proper engineering answer
> > from
> > perhaps a Boeing engineer. Again the question is
> > which is stronger when attaching a thin and thick
> > piece of metal together - a rivet where the mashed
> > end
> > is against the thin metal or thick metal? I say the
> > thick metal as is confirmed by Vans.
> > __________________________________________________
> > Do You Yahoo!?
> > Check out Yahoo! Shopping and Yahoo! Auctions for
> > all of
> > your unique holiday gifts! Buy at
> > http://shopping.yahoo.com
> > or bid at http://auctions.yahoo.com
> > Van's Air Force - World Wide Wing
> > www.vansaircraft.net
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> __________________________________________________
> Do You Yahoo!?
> Check out Yahoo! Shopping and Yahoo! Auctions for all of
> your unique holiday gifts! Buy at http://shopping.yahoo.com
> or bid at http://auctions.yahoo.com