Tips for Steel Tube Construction
By Frank R. Libertif (originally published in EAA Sport Aviation, May 1994)
I am a Technical Counselor, an EAA member and a member of EAA Chapter 176. When building my Tailwind, I fabricated several fixtures that should be useful to others using steel tubing construction.
This fixture is for welding aileron and flap fittings for controls having round steel spars. The shaded area is steel bar (1/8" thick x 1-1/8" wide).
Jig fixture for making elevator hinge fittings.
A = Stationary round bar fastened by machine screw drilled and threaded on opposite side shown.
B = Movable bar slides up to round bar when round tubing is slipped on its radius and round bar. Two screws fasten it tightly against A.
C = 1/4" thick bar.Top and bottom fittings are clamped on B, and spot welded. Then fitting is slipped off jig fixture and welding is completed.
This fixture is for accurately drilling round steel tubing. Drill one side, then the other, with undersized drill bit. Then line bore with a finish size bit.