Drilling a hole in Aluminum Rib; how close?

[Michael Horowitz]

I'm trying to align the holes in the leading edge sheetmetal with the
existing holes in the ribs. Sometimes they line up, sometime I can see
the hole in the rib, maybe 1/2 screw shank thickness away (in which
case I use a Dremel bit to enlarge the hole in the sheetmetal in the
direction of the rib hole) and in some cases I'm more than a screw
shank's distance away, so I'm going to have to drill another hole in
the rib. Question is how close can screw holes in ribs be before I've
weakened the rib?
If this were wood I'd enlarge the hole, glue in a dowel and redrill
the hole. What's the equivalent when drilling holes in ribs? - MikeH

[[email protected]]

On Oct 14, 4:32 am, Michael Horowitz > wrote:
> I'm trying to align the holes in the leading edge sheetmetal with the
> existing holes in the ribs. Sometimes they line up, sometime I can see
> the hole in the rib, maybe 1/2 screw shank thickness away (in which
> case I use a Dremel bit to enlarge the hole in the sheetmetal in the
> direction of the rib hole) and in some cases I'm more than a screw
> shank's distance away, so I'm going to have to drill another hole in
> the rib. Question is how close can screw holes in ribs be before I've
> weakened the rib?
> If this were wood I'd enlarge the hole, glue in a dowel and redrill
> the hole. What's the equivalent when drilling holes in ribs? - MikeH

Typically two diameters from the edge of the sheet. If you got
the hole too close, I suppose you'd need to rivet a strip into the rib
flange and redrill.
Which airplane uses screws to attach sheet metal? Is this a
Champ?

Riveting info that would generally apply, I think, to screw
holes is found on page 4-20 of this link:
http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2004.pdf

Dan

[Darrel Toepfer]

wrote:

> Which airplane uses screws to attach sheet metal? Is this a Champ?


My Pacer does, so would the 3Pacer...

[Don Lewis]

"Darrel Toepfer" > wrote in message
. 18...
> wrote:
>
>> Which airplane uses screws to attach sheet metal? Is this a Champ?
>
>
> My Pacer does, so would the 3Pacer...

Luscombe also............

[Steve Hix]

In article >,
" Don Lewis" > wrote:

> "Darrel Toepfer" > wrote in message
> . 18...
> > wrote:
> >
> >> Which airplane uses screws to attach sheet metal? Is this a Champ?
> >
> >
> > My Pacer does, so would the 3Pacer...
>
> Luscombe also............

The B-25 I was looking at this afternoon used 'em. (Some local guy found
a flyable B-25 and brought in to San Martin, CA over the weekend. Now
his group is looking for volunteers to restore it. No idea where he
found it.)

[Michael Horowitz]

T'craft - Mike

On Sun, 14 Oct 2007 10:24:03 -0700, wrote:

>On Oct 14, 4:32 am, Michael Horowitz > wrote:
>> I'm trying to align the holes in the leading edge sheetmetal with the
>> existing holes in the ribs. Sometimes they line up, sometime I can see
>> the hole in the rib, maybe 1/2 screw shank thickness away (in which
>> case I use a Dremel bit to enlarge the hole in the sheetmetal in the
>> direction of the rib hole) and in some cases I'm more than a screw
>> shank's distance away, so I'm going to have to drill another hole in
>> the rib. Question is how close can screw holes in ribs be before I've
>> weakened the rib?
>> If this were wood I'd enlarge the hole, glue in a dowel and redrill
>> the hole. What's the equivalent when drilling holes in ribs? - MikeH
>
> Typically two diameters from the edge of the sheet. If you got
>the hole too close, I suppose you'd need to rivet a strip into the rib
>flange and redrill.
> Which airplane uses screws to attach sheet metal? Is this a
>Champ?
>
> Riveting info that would generally apply, I think, to screw
>holes is found on page 4-20 of this link:
>http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2004.pdf
>
> Dan