3/4"OD 4130 now on hand, and all tubing for mount cut, notched, deburred and the ends polished. Ready for the welder, so go back to welder #2 with such joyous tidings. No response to phone calls/messages/emails. The work-shy swine is ghosting me... Giving up on the support of the amateur world I ask an engineering contact for assistance, and he gives me the number of the welder he uses. The lovely chap seemed quite bemused to discover there were amateur builders out there who just didn't pull parts out of boxes, and has invited me to bring my stuff and discuss it. This could be PROGRESS!