I was confronted with the problem of swageing/swedging holes in the 
bottom of an aluminum fuel tank for an airplane I am building.  I 
posted to the aircraft homebuilt, welding and metalworking newsgroups.  
After several suggestions I set about making my own version of a swage 
block and die.  Apparently the original swage tools were with blacksmiths.  
They would have a block with several different sized holes and a tapered 
die that would be used to form the holes.  My project only has five holes 
that needed to be swaged but I thought this would be a good learning 
experience and I was curious about the results.  

The first picture shows the swage die parts.  The only part I had to 
make was the bullet shaped male die.  I purchased a 12"x 2.25" piece 
of mild steel bar and turned down one end to form the die.  The female 
portion is a short 3" piece of plastic well casing with two hose clamps 
tightend down to support the edges of the pipe.  A 4.5" carriage bolt, 
a large washer, two smaller washers and a nut complete the parts list.

To use the swage I drilled a pilot hole 1.25" with a hole saw into the 
..090" aluminum (5052). The male die is held up under the pilot hole and 
the female pipe is centered over the hole.  The bolt is inserted through 
the male die, pilot hole, female pipe, the washers and finally the nut 
is screwed down tight.  A little tapping to get the whole thing centered  
and it's ready to tighten down.  I sprayed a little lubricant on the 
threads and around the  male die and started to torque down the nut.  

Surprise, surprise.  The die pulled through the pilot hole and the 
aluminum was formed against the inside of the female pipe.  I got lucky 
with the plastic casing as it only required a little sanding on the 
inside to provide just the right amount of clearance for the male die 
and the aluminum.  As the aluminum is .090" and the fuel tank fitting 
is 1.875" I made the female die with an ID of 1.875"+.180".

The remaining pictures show the results of a coupon I tried.  The number 
five represents the fact that there were 4 unsuccessful attempts before 
I "perfected" my technique. Other pictures show the fuel tank fitting 
inserted into the swaged hole.  With the .090" aluminum I found I could 
swage a hole no closer than .75" from the edge of the aluminum.  Any 
closer to the edge and the aluminum deformed more than I wanted to deal 
with.  The male die is equal to the diameter of the fuel tank fitting.  

A lot of work for five holes eh?