Originally Posted by
nazcalines
Why not use round tubing instead of square?
I did have this thought. Round tubing often is available in nice seamless telescoping sizes and can be easily cleaned inside and out with reamers and drills and lathe tooling. Production is, indeed, easier. Singer did it this way. However, square locates the derailleur in torsion. The handle should indeed do this, but I thought that a "belt-and-suspenders" redundant approach was appropriate since I'll be brazing it on.