<September 4, 2007>
Longeron Bending - Part III
Finally back at it for longeron #2. As with most anything on this project that you do two times, the second time goes much quicker. After about an hour and a half in the shop tonight, the longeron is about 80% of the way to be complete.
I was actually a little anxious about starting this job. Anxious may not be the best word here, but I think you know what I mean. I talked this over with a few builders who are further along than me, and they all said the same thing. Get it as close as you can, but donít worry about it being perfect. I think I'll heed their advice.
I know I said I would take pictures, but it is hard to bend and work the camera at the same time, so I guess words will have to do. I pretty much followed the instructions here. After I had marked the location of the bend I made little tick-marks on the longeron every inch or so to help me to determine how far to move the longeron each time. I started by clamping the longeron in the vise about an inch behind the aft mark, and while bending the longeron down with one hand, I used the other hand hit it with the rubber mallet. A few good whacks (3-5 depending on intensity) was all I would do on the first pass. Then I would release the vise, move the longeron an inch to the next mark, and repeat the process working my way forward. Every three marks (inches) or so, I would take the longeron out of the vise and compare it to the paper template. While I was pre-loading the longeron with my hand, I would also make sure I was bending it in a direction on the second axis that would counteract the longeronís tendency to bend in an unwanted direction. In addition, every so often I would also use my adjustable wrench or seaming tool to help me remove the twist from the longeron.
Hmmm, what can I say about this picture. The longeron is clamped into the vise at the aft mark and ready for bending. All the banging with the hammer really rattled the heck out of all the parts stored on the shelves of the worktable.
After a bit, I found it easy to adjust things by hand. I rotated the longeron 90° in the vise and pushed (bent) it by hand. In some cases I ended up with a smoother bend by using this method. Actually, I ended up overbending it a bit when using my hands. Turns out you donít need as much force as I thought to bend these things. The good news is that is was relatively easy to lessen the bend by just giving it a slight pull instead of a push. I got it pretty close to the template at this point but I was starting to get a little frustrated as you make an adjustment somewhere, and it seems to have an effect on somewhere else, so rather than fighting it, I called it a night and I will pick up here at a later time and with a fresh mind.