Does your friend have a time schedule they would like it done? I assume the use of words like probably means the materials need to be acquired yet. Will they be procuring the base materials and need help with cutting/grinding and welding or do they want a turnkey part?
I might be able to help, but it would be a while. I won’t be back in town until Feb 9th.
I know there are more proficient TIG welders out there to weld metal this thin. I would be willing to plasma cut the parts if someone wanted to do the welding. If there is some sort of notched curve to mate with a part let the computer do it, but someone could just hand grind the curve to match.
You specify 4130 alloy with thickness. Any specific filler alloy?
I assume this is a bracket mating to a 1.75" od tube. Assuming it will be rotating about the central axis. If sliding then I would guess orientation would flip 90 deg and be a straight weld.
I could not figure out from the description if it a bent sheet or larger tubing 1.75" id that slips over.
I assume since there is no dimension for the control rod it will be drilled later to match some hardware.
Short of a basic sketch with dimensions just many assumptions is this what they want?
If possible later after the part is done if someone else helps out could you upload pics of the part?