Is this bad?

[Chewie]

Some of my nose ribs are doing this at the very front edge of the top and bottom flanges (hope you can see in the picture). Once it's set the lip is difficult to flatten out, so I'm wondering if i can just leave it alone. Any thoughts? Thanks as always! Mark

[Jflyer]

I've been testing out some form designs and have seen that a few times well. It appears the relief hole may need to be further back into where that buckling is. I corrected mine with a small 'rat tail' file. It elongated the hole slightly, but I don't like that buckling. I feel it will be a good place for cracks to start that I may not see until later. As is during the first annual. :-)

[DRLPatrol]

Would fluting before you get all the way to 90* help? It seems the extra metal is just looking for some where to go.

Doug

[Chewie]

That was my thinking. Seems to help if I ease off on the ends when it's still in the block. I just don't know what to do with the ribs I've already done that show some buckling to varying degrees. The photo above is probably the worst example.

[alaskabearhawk]

Something in the forming process is amiss. It looks like the backer of the form block either doesn't go far enough toward the tip of the rib, it is too narrow at that point or not enough pressure is being applied at that point, letting the metal take the path of least resistance and bowing out.

[X'N]

When your bending it over in your form, before you remove it. Take a piece of maple about 2" wide and work the edge of the metal around the form tapping the wood block. It helps the radius to take a set.

Also are you clamping the form and backer to the bench when your forming them? A screw in the jig hole may not be enough pressure to keep a form tight.

[Chewie]

The backer is offset about 1/8”. I'm getting flat ribs now, but I have that batch of 16 to address. It seems the general consensus is "this IS bad" and I should fix them somehow, or replace them.


Dan, to that end are you suggesting I plop my existing ribs back in the blocks? I tried hammering and mashing out those divots before, no luck. A different method or tool perhaps?

[X'N]

The offset backer is most likely the problem. All my forms are the same size so I can bend left or right on them and thats why I have to use the maple hunk to get in there and get a tight bend.

My guess is with the ribs now fluted you won't be able to put them back on your form, unless you back cut your form to clear the flutes.

With that said, before I remade them I would call Bob and get his input. My guess would be they will be fine as is.

[N3UW]

I agree with X'N. I do not think it will be an issue. It is simply the front edge of the nose rib. You will most likely be fine so just check with bob and see what he says.

[geraldmorrissey]

Cut some of them up for small parts. Keep a couple for wall decorations and use the rest for test articles, you'll be glad you did. Unfortunately 100% of your effort will not end up as primary structure. You will produce scrap. Now is one of those times. Be glad the parts are small and inexpensive. Be happy because your next effort will be much better and you will sleep good at night. Forming hard AL is not easy and takes some effort to learn. If these are your first attempts, try forming some center ribs to get a feel for it. The upper surface curvature is not nearly as bad. Spray for red paint on the bad parts so they do not end up in the structure. I've seen a rivet gun with a padded flush set used in areas like this, but I like X'N's idea of a separate tool to address this area along with lots of clamps.
Good Luck
Gerry
Patrol #30

[Chewie]

Practice spares are good...
I will call Bob. Do you guys have some close-up photos of the front of your nose ribs? I'd love to see how others are navigating that curve.

[Chewie]

Update: Bob said not to worry about the minor buckling, as long as the outer profile is maintained and there are no observable cracks.