It is not uncommon when building an aluminum airplane to need to adjust the finished angle of an aluminum extrusion a bit. Closing up an angle to less than 90 degrees is easily accomplished by putting the part in a vise and hitting it with a hammer. Opening up the angle can be a little trickier. For a short piece, here’s a simple trick. In the tail of the Xenos motorglider, you have to open up a 2-inch length of 2x2x1/8-inch angle from 90 degrees to 95.1 degrees. Aside from not knowing how to measure that 0.1 degree, the bending was made easier with a claw hammer and my big Chinese vise.
The block of wood makes it easier to slide the claw of the hammer in there, and then a little pull back on the handle opens the angle a little. In this case, careful measurement showed that I got it to 95.5 degrees—but a quick rap with the hammer drove it back down to where it needed to be:
A quick pass on the belt sander took the little bit of curve out of the outside flats, and it matched the drawing—as close as I could tell.
Opening up a short piece of aluminum using a vise and claw hammer.
A block of wood makes it easier to slide the claw hammer into position.
