Creating a swaged hole in the bottom of a fuel tank.

That's good to know. I'll keep on this track then. I did hear from another
lister that surface welds the bungs over slightly undersized holes with good
success. That will be my backup plan but for now I am to far into solving
the swedge problem to drop it at this point. Plus I'd like to know it
works.

Eb



"Rich S." wrote in message
...
"Ebby" wrote in message
...
The EAA states that building your own airplane is educational. Well I'll
say!! I spent the day down in my shop working on the swedging problem.
I am pretty sure I have the answer to what needs to be done. As the
alloy is 5052 and .090" in thickness, it seems to hve good workability.

Ebby ..............

One of the Emeraude builders of my acquaintance faced a similar problem.
He needed to construct a "pass-through" in the center of his tank to allow
the carburetor cables to penetrate the aluminum. In his case, he swaged
matching holes in the front and back of the tank and then welded a piece
of tubing through and through. He built a swage similar to a chassis punch
and it worked rather well.

Regards,
Rich S.

If anyone is interested, I worked out a solution to the swage problem.
Thanks to input from three different newsgroups I successfully am now able
to swage holes for my aluminum fuel tank. To view the results go to the
metalworking.com dropbox and look for the files called "SwageDie". I posted
them earlier today.

Thanks for the help.

Ebby


"Ebby" wrote in message
...
I'm thinking with .090" to stretch the hole would only be larger to accept
a larger bolt for stretching the swedge. Perhaps 3/8" instead of 1/4". I
have some experimenting to do.

Ebby


"Ernest Christley" wrote in message
.. .
Ebby wrote:
Ernest,

I think I understand your description. I am going to send you a picture
of how I interpret your instructions. To me it seems like the tool you
describe is similar to a radio chassis punch. Is that correct? Instead
of punching a hole, your device pulls a slug of aluminum through a hole
in the plywood 2x4 side of the aluminum.

Also are you saying that once the tool and aluminum are all clamped
together the hole dug out of the hole saw will press through the
aluminum sheet creating the swaged hole? I do have to mention that the
swage will result in a flanged hole that I can use to weld my finger
strainer and sight gauge fittings. Should a hole larger than the 1/4"
hole you mentioned be drilled in the aluminum first so the male swage
block will pull down through easier to create the flange.

I'm all ears to solve this fabrication problem.

Ebby

I think I answered you with direct email, but for the greater
audience.... I'd use the "chasis punch", as you describe it, to make the
swage and then use a step drill to cut the hole. That will help avoid
unwanted cracks around the hole from the stretching. You can make a
larger hole, but remember that you're stretching the aluminum. Keep the
hole as small as possible.



"Ernest Christley" wrote in message
...
Ebby wrote:
Dear All,

I am starting to build my center section fuel tank and need
information about how to swage holes in the bottom of the tank so that
I can edge weld the six fittings specified in the plans. Four of the
fittings are finger strainers and one is for the sight gauge. There
is one more hole on the top for the filler. As there are only six
holes in three different diameters, I was thinking about doing it
using simple hand techniques rather than expensive tooling.

Here is my idea. The tank is .090" 5052. I planned on drilling holes
(.180+flange dimension) undersize in the aluminum. Then centering the
holes over 3/8" steel plate with holes .180 oversize, then use a
polyethelene bossing hammer to swage the edge of the hole into the
female die hole. The holes in the female die would have the edges
relieved to accomodate a bend radius. It might be time consuming but
educational.

Any advice or previous experience to share

A piece of 1/2" plywood and a couple chunks of 2x4. Tack plywood to
one of the blocks and use a small hole saw with a 1/4" centering bit to
cut the inside diameter of the swage. The piece that you dig from the
hole saw goes on one side of the aluminum. Use a bigger hole saw,
centering on the same 1/4" hole, cut the outside diameter of the swage,
then drill the 1/4" hole all the way through the block. Drill a 1/4"
hole through the other block. Drill a 1/4" hole where the swage will
go.

Thread a sufficiently long bolt through a fender washer, the block with
the plywood attached, the aluminum, the piece you dug out of the small
hole saw, the other 2x4 block, then another fender washer. Spin a nut
down to extrude the swage.

I don't know if this will work on .090, but I've used this technique on
thinner material.

"Ebby" wrote in message
...
If anyone is interested, I worked out a solution to the swage problem. Thanks
to input from three different newsgroups I successfully am now able to swage
holes for my aluminum fuel tank. To view the results go to the
metalworking.com dropbox and look for the files called "SwageDie". I posted
them earlier today.

Good Job!

The journey is half the fun, right? g
--
Jim in NC