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best way to cut corrugated sheet metal
- Thread starter Janger
- Start date
I’m not sure 1.5” maybe 2”
TorontoBuilder
Ultra Member
I used to work every day with sheet metal in my 20s and 30s, but if also done a few metal roofs with corrugated and standing seam metal. I have a couple varieties of power snips and they did work okay but the best is a circular saw, fast, it cuts straight with little user input and if you buddy splurges for a metal cutting blade he (or she) will have an easy time of it
I don't have @TorontoBuilder's level of experience, but I did do a steel sided building and two steel roofs. I tried many methods including snips, a power snip, a cutting wheel, a nibbler, a scroll saw, and prolly a few I've forgotten. Nothing worked better than a skill saw with a carbide toothed blade on backwards. I could easily imagine a metal cutting blade might be better but after I discovered the backward blade I stopped looking for better alternatives so I really don't know. If I ever have to do another one, I'll take the time to find and try a metal cutting blade.
So the blade gullets don’t grab the metal. If you have a metal cutting blade it doesn’t matter but I’ve cut many hundreds of feet of corrugated roofing with a framing blade installed backwards.
ChazzC
Well-Known Member
Deep corrugations, and the material looks like SS.
In addition to ear & eye protection, I'd recommend tight fitting gloves and a face shield. Three stories up I'm assuming he'll be tied off, will have the tool tethered and wearing a safety cap (bump or helmet).
I think @DavidR8 has the right of it.
My theory is as follows: A blade turning the correct direction will work if it is fed into the work with a very slow controlled feed. But we humans are not capable of this kind of control. We get impatient and push too fast looking for the optimum speed. When the blade turns backward, there is no sharp tooth to grab the sheet metal and catch so control is not needed - just push and let it do its thing. Turning backward is like slapping the sheet metal continuously with the back side of each tooth. It is aggressive but can't grab.
TorontoBuilder
Ultra Member
It's the same principle as a negative rake angle of a blade on a radial arm saw, less grab.
A metal blade performs better than a reversed blade for two reasons though, the first is that the blades typically have very low to zero rake (mine has zero rake) so they perform better than a negative rake but they dont grab because of the low rake angle and the gullet and projection design, The second reason is that the teeth are typically set on a long protrusion with is a slightly raised nub behind the carbide so that the blade does not sink deeply into the cut, but rather rides on the carbides and then the nubs for the smoothest
Gunna hafta get me one of those blades so I have it next time I need it.
Besides, that's the very best way I know to make sure I never need it........
TorontoBuilder
Ultra Member
They're great for cutting aluminum extrusions in a chop saw.
I have heard people cut steel tube and such with them but I never had the nerve to try. I use abrasive blade for that. But one day I'll give it a go when I need to weld up precision parts
Can we watch? Heck, I'd even watch a YouTube video to see that!
Ya, that is another point...... Noise! Even a backward blade on sheet aluminium sounds like somebody is stepping on a cats man parts.
If I lived 1000 ft from my nearest neighbor I'd go for it but since I'm less than 30 ft away a cold saw like an Evolution is likely a non-starter.