That is what I thought, there is no need for the back cut because on the second 45 it will fall off.

The ability to ‘back cut’ (180) becomes increasingly handy as you work with tubing size 1 1/2 and greater. Any size less and you can cut straight through.

If you’re referring to the ever-so-small jog where the cuts meet, then you are correct, it’s not absolutely perfect. But not because the 180 jig is off. We’ll chalk it up to user error! That jog would be perfectly acceptable to most fabricators considering that it’s not off by more than a 1/4 of a degree.

syncnotcher you would need to secure both ends of the guide to prevent flex in it, perhaps some sort of quick release slider with a pivot underneath? imagine kind of like an alternator belt tension bracket with a slot on one end that you can bolt up into your guide rail, if you use a quick clamp like you get on bicycle seats and axles you won't need any extra tools to adjust it either. or even an arced slot in the base plate that follows the radius of the guide with a quick release bolt through.

Buckhorn Cortez. quiet

So then if the shitment don't fitment you can't wear it...?

1. (Mechanical Engineering) machinery an accessory attached to an assembly of parts 2. (Furniture) chiefly Brit a detachable part of the furnishings of a room

And there is no "fitment" as used in this video as he's referencing the fit of the pieces together as in, "Notching the tube here and here for a clean fitment." An obvious misuse of the word "fitment" as clarified by the definitions you've provided to make my point. Thanks!