In our quest to make more fittings, we discovered the internal style flying/landing wire fittings call for 4 attachment pieces to be made out of 7/8"X1 3/4" X .100 4130 rectangular tube. I tried the obvious sources including ACS, Wick's and online metals. None have anything like it. Have any of you guys found a source for this or are you bending it up from .100 sheet?