Caveat: today's pool of candidates is unusually weak — most entries are hashtag-spam uploads with no descriptions or generic "welding tips" Shorts. This pick is the least bad option, and even it is a Short with clickbait styling.

That said, the underlying technique is genuinely useful for anyone doing pipe fabrication. Getting a clean 45° miter on round stock is one of those small skills that separates tidy work from ugly work, and freehand marking almost never gets you there. The traditional shop method is to wrap a piece of paper or a proper contour template around the pipe, but there are also quick geometric tricks using a square, a piece of angle iron, or a folded strip of stiff paper to project the ellipse onto the surface — any of which get you a scribe line that a grinder or bandsaw can follow accurately.

A tight, well-marked 45° cut matters because the fit-up dictates the weld. Gaps and mismatched bevels force you to bridge with filler, which distorts the joint, wastes rod, and produces weaker, uglier beads. Good marking upstream means less grinding, less gap-chasing, and a root pass that actually flows the way it should.

Worth 30 seconds if you fabricate handrails, exhaust, roll cages, or any mitered tube work.