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Materials Used
Tools Used Metal band saw, Drill press, #10 drill bit, 1/8 drill bit, 9/16 drill bit, Metal cutoff wheel, MIG welder, Oxy/Acetylene welder with Meco torch and #3 tip. ERS 80-sd2 filler, bench grinder and scotch brite wheel. Procedure I first contacted Rick Crisenbery at Crisenbery engineering here in Fairbanks to see about having him machine the bearing support pieces. After looking over the drawings Rick said he could machine the parts using CAD/CAM equipment if I was willing to pay the set up fees. I agreed and Rick now has all the programs written to produce as many as needed . His work was exceptional and fit perfectly.
I next began by transferring all the dimensions and layouts for the Flap hinges to AutoCAD and printed out drawings that could be used for templates.
The next step was to build the welding jig using a piece of 1 1/2 X 10" square steel tube and a piece of 1/4 X 4" X 10" steel plate and a piece of 1/4" X 1" X 2" Steel flat bar. I began by welding the steel plate to the 1 1/2 steel tube making sure the joint was a perfect 90 degrees. I then drilled a 1/8 pilot hole in the end of the 1/4 flat bar and cut it off to the required height. I positioned it with a CAD drawing glued to a scrap piece of .032 aluminum and welded in place with the MIG welder. This is the basic welding jig with parts in place for welding. (note the 1/2 in socket was a perfect fit in the 9/16 hole. I used it for cutting and fitting then used the 9/16 bolt for tack welding.)
The parts are prepared as follows. The round disks were punched out of a sheet of 4130N .080 steel plate by my local machine shop. I had to dress them down on the grinder to remove the sharp edge after drilling the center hole out with a #10 drill. note the center dimple left by the punch is perfectly centered.
I then cut 14 1 inch long pieces of 3/8" 4130N .095 tubing on the metal band saw and reamed to 3/16 ID and buffed and deburred the ends. Next using #10 X 1/1/2 machine screws, nuts and washers, a steel disk and 1 inch tube was bolted to the welding jig at the desired locations. One of the bearing support pieces was bolted to the jig and the straight pieces cut and ground to fit. The short bottom tube has a curve to it that I created using a rigid mandrel pipe bender clamped in the shop vise. by bending a little and then sliding the tube up in the bender a very controlled and accurate amount of bend can be applied to the tube without crushing it.
Cut and grind the curved tube to fit per drawings and place in welding jig. I found that if all the pieces were cut and fit properly they all stayed in place for tack welding without any other aids. Repeat the process for each of the hinges and finish weld.
Completed April 12 2004, Total time 8 hours.
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