Metal circle cutting

I thought this was a creative way to cut circles with less labor using a common angle grinder.

i like the idea but i remember my 4" hole cutting in 3mm ss sheet

as long as its over a certain size circle it should do it even on 3mm 5mm maybe a bit of a problem due to thickness of the steel and the grinder

i found with mine cut the hole a little smaller and widen it with an angle grinder is how i got my hole cut into it



you can actually see the resting circle groove marks on the steel itself as i rounded it off on the steel

I find the easiest way is to blag the use of a friendly machine shops plasma cutter ;-)

Yes but what if you do not have access to a machine shops plasma cutter:>(
I was posting this for those who do not have access.:>)

The second and third video gadily was very cool, it is acting like a lathe.
Fantastic idea for one who could build something like that!

someone did using a nibberler tool

Good find Gadily!

I worked with a plumber early in life, and learned how pros cut circles and other shapes in sheet metal with aviation snips, aka compound snips. Punch or drill a start hole somewhere near the center and start a spiral cut in the direction your snip dictates, removing as narrow a strip as manageable until the spiral merges with your line. The spiral can be somewhat square shaped if that's what you're cutting. If the hole is extreme diameter and heavy gauge, making the start hole with as big a hole saw as you can should help. The secret is cutting a narrow waste strip that easily curls up and out of the way as you work your way around and outward. I am only 125 lbs. and I can snip 20 gauge stainless(.032). For cutting holes in the side of metal drums and such, you can't beat this method unless you have a plasma cutter.

I am a retired Tool & Die maker and was impressed by the grinder/large circle cutter he threw together in the first video. However, cutting circles that large seems beyond the scope of RS construction, and I would like to point out problems using that method for cutting the smaller circles that are used in RS construction. Especially in the thicker materials, the smaller diameter and thicker the material will require huge amounts of kerf to be formed as the straight blade makes an ever widening curved groove. The deeper you grind, the wider it gets. Every time you change discs it will cut different, and it will take more than a few discs to get through something like the 1/4 inch plate in the other video. I'm not sure it's practical, but I hope somebody tries the first circle method to make one, with 1/4" steel, the size of a typical RS heat exchanger cap and proves me wrong.

Nice info guys! If you cut the thicker material about half way through, then flip it over, you might be able to cut it without so much curf.