I clamped the 4130 tube in my vice, mashed the ends together then fired up the torch. Heated the tubing so that I could make a nice smooth bend. I compared the tubing bend to the bend in the aluminum tube I had previously mocked up and continued the bend until they matched. Cooled the tube and checked fit to the oil cooler bracket—looks good, marked for the second bend and went thru the procedure again. Looks like this will work—so I drilled a ¼” hole in one end and a #12 in the other end. I found a longer screw which I ran thru the valve cover and tightened it down. Added the tubing and a nut, then secured the other end. Clecoed up all of the #4 oil cooler baffle parts and mounted the oil cooler. Then I added one more piece of angle to tie the vertical 1” corner angle to the side baffle. Now I can shake the airplane with the oil cooler, but the baffle does not move—hope it stays that way at least until engine overhaul! I removed the rear baffle and side baffle while everything was clecoed together just to be sure I could get it off. I reamed all of the 1/8” holes to #30 and all of the 3/32” and #41 holes to #40. Also reamed the angles where the bolts pass thru to #12. Then I spent a good deal of time figuring out the order to rivet all of parts together. Next up, deburr, edge finish and dimple/counter sink as needed.
Tube brace in place
Mounted oil cooler and shook the plane
Final (I hope) angle to beef up the oil cooler mount-required a .040 spacer