Bill,

                  Thanks for putting the brake on line. I might as well give everybody
                  some background info on bending leading edges. My first attempt at
                  bending a leading edge was to take a 4' x 10' piece of alum and bend it
                  until the 4' edges touched. Almost impossible, especially by yourself.
                  First attempt to fold it resulted in a kink on one side. I figured that
                  could be the bottom, and tried again. Another kink. Trash one piece.
                  Second attempt, I screwed a 1" x 4" piece of wood to one edge. Folded it
                  over and screwed the other edge to the 1 x 4 (not easily). Then I took a
                  2 x 8 and started mashing the whole mess down. Eventually, it looked
                  like it might be OK, so I took the screws out, marked a leading edge
                  centerline, laid out all the holes and the shape, then cut it to size.
                  Cut a template to check the leading edge radius- found much more bend at
                  the ends than in the middle. Trash #2 attempt. Decided it was time to
                  quit wasting alum and come up with something that would work on the
                  first try. I made a 4" press brake to experiment with spacing on the
                  female die. After a few attempts, I was able to get the radius and bend
                  angle called for in the plans. Cut another leading edge to final shape
                  and drilled all the holes, popped it in the brake, and out came a
                  perfect (at least I thought so) leading edge. When somebody is ready,
                  I'll write up how I chose to install it. Did some experimenting to
                  determine size for the dies for the tailfeathers, amd made a four foot
                  version of the big brake. Also cut tail skins to final shape and drilled
                  holes before bending. Any questions, give me a holler.

                  Tony Spicer, Sonex #32

______________________________________________________________________________

                  Message: 2
                     Date: Tue, 23 Feb 1999 13:00:32 -0700
                     From: Bill Von Dane <bvondane@atmel.com>
                  Subject: Sonex Press Brake

                  Press Brake for Wing Leading Edge Bill of Materials:

                  1 1/4 EMT conduit (1 1/2 OD) Lowe’s part# 72717
                  1 each 2 x 10 x 10’
                  1 each 2 x 8 x 10’
                  1 each 2 x 4 x 10’
                  2 each 3/8 drop in concrete anchor (Lowe’s part #76422)
                  2 each 3/8 coupling nuts
                  2 each 3/8 threaded rod 3’ 1 1/2 x 1 1/2 x 1/4 scrap alum
                  2 each 2 1/2” drywall screws
 

                  Select the straightest lumber available.Draw a centerline on 2 x 8. Measure
                  15/16” on either side of centerline and draw two lines. Using drywall
                  screws, attach the 2 x 4’s to the 2 x 8 on the 2 lines. This will leave a
                  3/16” gap on either side of the conduit. Draw a straight line down the
                  conduit. Measure halfway around (2.36”) and draw a second straight line
                  (make two marks 2.36” apart on a piece of card stock to measure). If you’ve
                  done it right, the two lines will be 180 deg apart. Measure in 4” from each
                  end and drill a 1/2” hole thru both sides of the conduit. Drill a 3/16” hole
                  every 12” down both sides of the conduit. Countersink one set of holes.
                  Drill 1/2” holes on centerline of 2 x 8 to line up with holes in conduit.
                  The next step is to drill 1/2” holes in the ends of the 2 x 10. It can be
                  very difficult to drill a straight hole thru the 2 x 10. The easy way is to
                  have a 2” x 5” hole on the side at each end that is centered on where the
                  1/2” hole will be. With that, all you will need to do is drill a short 1/2”
                  hole down from the top and another up from the bottom. Screw the conduit to
                  the 2 x 10. File any protruding screw heads. Lay out two holes on the floor
                  that are the same distance apart as the 1/2” holes. Drill 1/2” holes in the
                  concrete floor deep enough for the anchor to sit flush. Whack the anchors
                  with a center punch and big hammer. Cut the threaded rod in half and insert
                  into the anchors. Bend rods until plumb. Do not try to anchor the 2 x 8 to
                  your workbench. IT WILL BEND THE BENCH! Place 2 x 8 over threaded rods. Shim
                  any low spots between floor and 2 X 8. Drill a 3/8” hole thru the 1/4”
                  aluminum. These will be heavy-duty washers. Place the 2 x 10 on the threaded
                  rods, then add aluminum plates and coupling nuts. A regular nut might work,
                  but I wanted the additional contact area the coupling nut provided. Put
                  blocks under each end of the conduit to provide clearance for the skin. At
                  each end of the skin, make a mark 15/16” on either side of the skin
                  centerline. Put skin on press and line up marks with the edges of 2 x 4’s.
                  Remove blocks and allow conduit to rest on skin. Check marks again. Tighten
                  one nut just until the skin edges start to raise, then go to the other end
                  and repeat. Alternate 3 turns at each end until everything bottoms out. You
                  can either start out with the press and get it right the first time, or
                  trash several pieces of aluminum, then build the press (like I did).

                  Changes for Tailfeathers

                  Use a piece of 1/2” conduit (5/8”od) screwed to a 1x8x4’ for the male die.
                  Use 2x4’s spaced 1 5/16 apart for the female die. Make sure male die centers
                  in female die and that it is perpendicular to female die.

                  Tony Spicer Sonex #32
 
 
 

                  _______________________________________________________________________________
                  _______________________________________________________________________________