The Murphy Builders Site

I realized today, well confirmed what I already suspected actually, that
some of the SS rivets mushroomed heads inside the end plug will interfere
with each other. Specifically, the two at the corners of the skin that go
through the spar into the end plug side wall at the horn end will

with the adjacent ones that attach the horn to the end plug. I thought

this possibility with regards to the AN-3 bolt threads interfering with

3/16 rivet that goes through the end ribs small flange and lines up

with the bolt coming through the end. I avoided that conflict by locating
those rivets as far away from the ends of the spar as possible. With the
skin corner rivets though, I figured the holes are located already, so I
just drilled them. Bad plan. I haven't riveted anything yet. Any
suggestions? It seems like the manual leads you right into this one. I was
thinking about just riveting the horn to the end plug and then trying to
drill off the mushroomed head enough to get clearance for the other rivet,
but with stainless I don't know if this is possible. I don't see another
option except to leave two rivets out of the horn/end plug connection.

S.S. rivets and a 3/16 bolt should be strong enough, but we're talking

ELEVATORS here!

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I realized today, well confirmed what I already suspected actually, that
some of the SS rivets mushroomed heads inside the end plug will interfere
with each other. Specifically, the two at the corners of the skin that go
through the spar into the end plug side wall at the horn end will interfere
with the adjacent ones that attach the horn to the end plug. I thought about
this possibility with regards to the AN-3 bolt threads interfering with the
3/16 rivet that goes through the end ribs small flange and lines up exactly
with the bolt coming through the end. I avoided that conflict by locating
those rivets as far away from the ends of the spar as possible. With the
skin corner rivets though, I figured the holes are located already, so I
just drilled them. Bad plan. I haven't riveted anything yet. Any
suggestions? It seems like the manual leads you right into this one. I was
thinking about just riveting the horn to the end plug and then trying to
drill off the mushroomed head enough to get clearance for the other rivet,
but with stainless I don't know if this is possible. I don't see another
option except to leave two rivets out of the horn/end plug connection. Five
S.S. rivets and a 3/16 bolt should be strong enough, but we're talking about
ELEVATORS here!

-----Original Message-----
From: mike.davis@dcsol.com
[mailto:mike.davis@dcsol.com]On Behalf Of Ken
Sent: Sunday, September 19, 2004 5:04 AM
To: rebel-builders@dcsol.com
Subject: Re: elevator end plug rivets


Jesse

Yeah after it is done you wish the manual had
suggested that you rotate
the rivet pattern in the horn 22 degrees to provide
clearance. What
Wayne said worked for me in a couple of places on the
airframe. Since
the stainless rivets provided by MAM don't expand
radially like the Avex
you can usually pull them by hand just a little,
remove the puller, then
tap them in a bit farther with a hammer (and perhaps a
hollow tube or
piece of wood with a hole slipped over the manual).
And repeat a couple
of times.

There's a couple of other non-critical places that
have a similar
problem. This technique doesn't work well with the
avex rivet but does
work somewhat with cheap aluminum pop rivets if you
simply can't get an
avex rivet in.

Ken

Jesse Jenks wrote:

I realized today, well confirmed what I already

suspected actually, that

some of the SS rivets mushroomed heads inside the end

plug will interfere

with each other. Specifically, the two at the corners

of the skin that go

through the spar into the end plug side wall at the

horn end will interfere

with the adjacent ones that attach the horn to the

end plug. I thought about

this possibility with regards to the AN-3 bolt

threads interfering with the

3/16 rivet that goes through the end ribs small

flange and lines up exactly

with the bolt coming through the end. I avoided that

conflict by locating

those rivets as far away from the ends of the spar as

possible. With the

skin corner rivets though, I figured the holes are

located already, so I

just drilled them. Bad plan. I haven't riveted

anything yet. Any

suggestions? It seems like the manual leads you right

into this one. I was

thinking about just riveting the horn to the end plug

and then trying to

drill off the mushroomed head enough to get clearance

for the other rivet,

but with stainless I don't know if this is possible.

I don't see another

option except to leave two rivets out of the horn/end

plug connection. Five

S.S. rivets and a 3/16 bolt should be strong enough,

but we're talking about

ELEVATORS here!

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From: Ken <klehman@albedo.net>
Reply-To: <rebel-builders@dcsol.com>
To: rebel-builders@dcsol.com
Subject: Re: elevator end plug rivets
Date: Sun, 19 Sep 2004 08:03:45 -0400

Jesse

Yeah after it is done you wish the manual had suggested that you rotate
the rivet pattern in the horn 22 degrees to provide clearance. What
Wayne said worked for me in a couple of places on the airframe. Since
the stainless rivets provided by MAM don't expand radially like the Avex
you can usually pull them by hand just a little, remove the puller, then
tap them in a bit farther with a hammer (and perhaps a hollow tube or
piece of wood with a hole slipped over the manual). And repeat a couple
of times.

There's a couple of other non-critical places that have a similar
problem. This technique doesn't work well with the avex rivet but does
work somewhat with cheap aluminum pop rivets if you simply can't get an
avex rivet in.

Ken

Jesse Jenks wrote:

I realized today, well confirmed what I already suspected actually, that
some of the SS rivets mushroomed heads inside the end plug will interfere
with each other. Specifically, the two at the corners of the skin that go
through the spar into the end plug side wall at the horn end will

interfere

with the adjacent ones that attach the horn to the end plug. I thought

about

this possibility with regards to the AN-3 bolt threads interfering with

the

3/16 rivet that goes through the end ribs small flange and lines up

exactly

with the bolt coming through the end. I avoided that conflict by locating
those rivets as far away from the ends of the spar as possible. With the
skin corner rivets though, I figured the holes are located already, so I
just drilled them. Bad plan. I haven't riveted anything yet. Any
suggestions? It seems like the manual leads you right into this one. I

was

thinking about just riveting the horn to the end plug and then trying to
drill off the mushroomed head enough to get clearance for the other

rivet,

but with stainless I don't know if this is possible. I don't see another
option except to leave two rivets out of the horn/end plug connection.

Five

S.S. rivets and a 3/16 bolt should be strong enough, but we're talking

about

ELEVATORS here!

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From: "Jesse Jenks" <jessejenks@hotmail.com>
Reply-To: <rebel-builders@dcsol.com>
To: rebel-builders@dcsol.com
Subject: Re: elevator end plug rivets
Date: Sun, 19 Sep 2004 08:05:40 -0700

Thanks,
Do you think I can partially remove the mushroomed head by drilling it off
or grinding?
Jesse

From: Ken <klehman@albedo.net>
Reply-To: <rebel-builders@dcsol.com>
To: rebel-builders@dcsol.com
Subject: Re: elevator end plug rivets
Date: Sun, 19 Sep 2004 08:03:45 -0400

Jesse

Yeah after it is done you wish the manual had suggested that you rotate
the rivet pattern in the horn 22 degrees to provide clearance. What
Wayne said worked for me in a couple of places on the airframe. Since
the stainless rivets provided by MAM don't expand radially like the Avex
you can usually pull them by hand just a little, remove the puller, then
tap them in a bit farther with a hammer (and perhaps a hollow tube or
piece of wood with a hole slipped over the manual). And repeat a couple
of times.

There's a couple of other non-critical places that have a similar
problem. This technique doesn't work well with the avex rivet but does
work somewhat with cheap aluminum pop rivets if you simply can't get an
avex rivet in.

Ken

Jesse Jenks wrote:

I realized today, well confirmed what I already suspected actually,

that

some of the SS rivets mushroomed heads inside the end plug will

interfere

with each other. Specifically, the two at the corners of the skin that

go

through the spar into the end plug side wall at the horn end will

interfere

with the adjacent ones that attach the horn to the end plug. I thought

about

this possibility with regards to the AN-3 bolt threads interfering with

the

3/16 rivet that goes through the end ribs small flange and lines up

exactly

with the bolt coming through the end. I avoided that conflict by

locating

those rivets as far away from the ends of the spar as possible. With

the

skin corner rivets though, I figured the holes are located already, so

I

just drilled them. Bad plan. I haven't riveted anything yet. Any
suggestions? It seems like the manual leads you right into this one. I

was

thinking about just riveting the horn to the end plug and then trying

to

drill off the mushroomed head enough to get clearance for the other

rivet,

but with stainless I don't know if this is possible. I don't see

another

option except to leave two rivets out of the horn/end plug connection.

Five

S.S. rivets and a 3/16 bolt should be strong enough, but we're talking

about

ELEVATORS here!

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-----------------------------------------------------

I just looked at it again, and I think I can work something out if I use
5604 (shorter) rivets in the two holes through the horn and end plug. Does
the mandrel have to stay in the SS rivets for shear strength? If not I
think
I can knock it out and with the 3/16 long rivet it just might clear.
Alternatively, I could countersink the hole slightly inside the end plug
for
the mushroomed head, and file the end of the mandrel down before setting
the
rivet.
Jesse

I just looked at it again, and I think I can work something out if I use
5604 (shorter) rivets in the two holes through the horn and end plug. Does
the mandrel have to stay in the SS rivets for shear strength? If not I think
I can knock it out and with the 3/16 long rivet it just might clear.
Alternatively, I could countersink the hole slightly inside the end plug for
the mushroomed head, and file the end of the mandrel down before setting the
rivet.
Jesse

From: Ken <klehman@albedo.net>
Reply-To: <rebel-builders@dcsol.com>
To: rebel-builders@dcsol.com
Subject: Re: elevator end plug rivets
Date: Sun, 19 Sep 2004 19:21:01 -0400

Jesse

I could be wrong but it seems clear to me from the specs that the
mandrel is not part of the rivet strength in any of the MAM supplied
rivets. Rivets that do allow for mandrel increased strength are usually
referred to as structural rivets and specify two shear strengths - one
for through the retained mandrel and another for any area that does not
have a mandrel retained in it. In other words my opinion is that I think
that it would be fine to grind off some of the excess length past where
the mandrel head has expanded the rivet. As I recall, in most of my
stainless rivets, that would not necessarilly remove the mandrel as the
mandrel head pulls down inside the length of the rivet.

There was a bulletin though about 06 and 04 length rivets in these end
caps. I could look it up but the gist of it was that there are some
places that are too thick for the grip length of 04 length rivets if you
measure or add up the thickness. Many years ago there was a mix up in
the manual or in the rivets that were supplied for these end caps and I
think the 04 are too short for the 8 rivets that go in from the end
through the horns. Last time I looked MAM had the grip length
(thickness) spec on their site for all the rivets. I think the 04 length
means they are good for 4/16 or 1/4" grip length max. which was OK for
the radial rivets through the tube and into the end cap but not good
enough for the rivets through the horn into the end cap.

Ken

Jesse Jenks wrote:

I just looked at it again, and I think I can work something out if I use
5604 (shorter) rivets in the two holes through the horn and end plug.

Does

the mandrel have to stay in the SS rivets for shear strength? If not I

think

I can knock it out and with the 3/16 long rivet it just might clear.
Alternatively, I could countersink the hole slightly inside the end plug

for

the mushroomed head, and file the end of the mandrel down before setting

the

rivet.
Jesse

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Ken,
I havn't seen the bulletin, but you are right about the grip length of 04
versus 06. The thickness of the end cap + horn is about 5/16, so right in
between. I was thinking of using an 04 and counterboring the inside of the
end cap for the mushroomed head about 1/16. This would provide clearance for
the opposing rivet, and get the correct grip length. I don't think that
would compromise the strength of the end cap, but I'm not sure. If I don't
do something, I'm pretty sure I won't be able to get the opposing rivet in,
no matter how hard I hit it.
Jesse

From: Ken <klehman@albedo.net>
Reply-To: <rebel-builders@dcsol.com>
To: rebel-builders@dcsol.com
Subject: Re: elevator end plug rivets
Date: Sun, 19 Sep 2004 21:48:59 -0400

Jesse

I don't think anyone can tell you to counterbore and I doubt that MAM
will either without seeing it but you could always ask them. It sounds
like you have dismissed the idea of grinding off excess length or there
really isn't any excess.

Would it help to take out the existing rivets and put in the other
(radial) ones first? - I think I did that somewhere.

Can you squeeze the installed rivet a bit shorter - ie hammer it like
you are installing a solid rivet?

Ken

Jesse Jenks wrote:

Ken,
I havn't seen the bulletin, but you are right about the grip length of 04
versus 06. The thickness of the end cap + horn is about 5/16, so right in
between. I was thinking of using an 04 and counterboring the inside of

the

end cap for the mushroomed head about 1/16. This would provide clearance

for

the opposing rivet, and get the correct grip length. I don't think that
would compromise the strength of the end cap, but I'm not sure. If I

don't

do something, I'm pretty sure I won't be able to get the opposing rivet

in,

no matter how hard I hit it.
Jesse

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