While watching South Main Auto, my favorite youtube channel, I saw a Eric O use a windows program called tubemiter to produce a printed template for notching a tube. I downloaded the program and it worked great. I even found a web version of it. I had to make some fence sections to repair my front fence and gate after my neighbors tree fell on it… Since I was only working with two joints over and over I made a 3d template with the two joints I needed on each end. One side is 34mm to 34mm tube and the other side is 34mm to 60mm tube and both at 90degrees. Made the repetative cuts easy.
Just slide it over the tube, trace the cut with a marker, and finish up with a cutoff tool…
Made a really nice joint for welding
Using OpenScad it was easy….
$fn=75;difference(){
cylinder(d=40,h=60);
translate([0,0,-2])cylinder(d=34,h=64);
translate([0,30,-6])rotate([90,0,0])cylinder(d=34,h=60);
translate([0,30,84])rotate([90,0,0])cylinder(d=60,h=60);
}