Is too much radius a bad thing?

[way_up_north]

Im working on wing rib formers...in the bearhawk builder manual it calls for a smaller radius then 1/8....on the edges..

but I have a 1/8 router bit...is there any harm in putting a bigger radius on the rib former..vs the sheet metal thickness...any loss in strength by going more then the minimum radius....

thanks guys

Michael in Canada..

[Chris In Milwaukee]

No problem at all, strength wise. Just make sure it’s not so big that you don’t have edge margin for riveting. Another option is just to knock the edge off with a sanding block.

[fairchild]

I just looked up those numbers the other day---
AC65-15a has a minimum bend radius on page 151. Min. Bend radius for .025 2024T4 is 1/16 and 3/32 for .032 inch.
I should think that best practice would be to keep your bend radiuses well above the minimum. I cant see how 1/8 would hurt- only issue i could see
like Chris said - if it shortened your riveting surface too much. You could take a piece of chromemolly steel sheet and make a scraper to drag along the sharp
wood corner to make a uniform radius. Or just carefully work it with a sanding block. I may try some minwax wood hardener on the edges where the pressure
is applied when the flange is bending. Not sure how well it works. (yet)

Tim

PS---- i am making my form block as we speak-

[Chris In Milwaukee]

That’s pretty much the way I did it. I drilled a 1/8” hole in a piece of scrap metal I had laying around, then used some snips to cut a 90°-ish notch tangent to the hole edge. I used that as a guide when I knocked off the edge with a sanding block to make sure I got it right. Or, if you,leave the edge kind of sharp, you can scrape it down to the radius. Depends on the type of wood you’re using if it will scrapes cleanly.

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