Cutting 20ga galvanized sheet

[JK22]

I have some of these. Once I figured them out,I was able to cut pretty straight. https://www.homedepot.com/p/DEWALT-18-Gauge-Impact-Ready-Shears-Accessory-DWASHRIR/305609180

 

[spitter]

The key to cutting sheetmetal with a cicular saw is to avoid any vibration wit the metal . Clamp the sheetmetal to your straight edge and have it supported on the bottom just out of the blades way . Slow steady pressure on the saw let it do the work ,avoid stops and starts in middle of cut . Any burs can be removed with flap wheel in a couple of seconds. Your basically just dressing it up . Once you get a few cuts under your belt you'll find it a cake walk. Just as easy as ripping plywood.:drink:

 

[Diggin It]

But again, it's all about the length of each cut. I can make a 12-18" (maybe up to 36") straight, clean cut with those shears in less time than it would take to set up for a circular saw cut. I got to where I only used the saw when I wanted to cut longer (up to 13') panels lengthwise.


Another option you'd have to test on some scrap ... You can score (with a razor knife), then bend and snap 29G roof panels. I don't know if you can do that with 20G Galvanized.

One more thought. With a circular saw blade, you lose 1/8" minimum with each cut. Shears mean no loss of material at all.

 

[Big Barn]

But again, it's all about the length of each cut. I can make a 12-18" (maybe up to 36") straight, clean cut with those shears in less time than it would take to set up for a circular saw cut. I got to where I only used the saw when I wanted to cut longer (up to 13') panels lengthwise.


Another option you'd have to test on some scrap ... You can score (with a razor knife), then bend and snap 29G roof panels. I don't know if you can do that with 20G Galvanized.

One more thought. With a circular saw blade, you lose 1/8" minimum with each cut. Shears mean no loss of material at all.

Totally agree.

And don’t forget there is even MORE material loss if a hand held electric shear is used. Maybe close to three sixteenths of an inch.

 

[chim]

For 20ga, the Harbor Freight shear would be nice. I use a DeWalt shear 18V Cordless 18 Gauge Swivel Head and Shear Kit - DC49KA | DEWALT for some things like that. If you're figuring closely on the material, be aware that each cut costs about 1/4" of material to make the "Spam can strip" of waste. The shears Diggin It used can cut on the line and require no extra material. Cutoff discs, circular saws and plasma do use a little.

Also use a cutoff disc in an angle grinder sometimes. Works best if the disc isn't plunged full depth.

Jig saw works OK, but 20ga is a little thin and the metal needs good support. Works better than a sawzall.

I've had better results using my plasma cutter on black metal. It needs more cleaning / attention when used on galvanized. Plus you shouldn't breathe the smoke.

Disclaimer - If I have time to plan and it isn't a Saturday afternoon project at home that I'm creating something on the fly, I can get the guys to shear it at work.

 

[Aquamoose]

You mentioned that you have air. Whichever route you take, you could benefit from an angle grinder with a debuting attachment (with twist-on pads of various coarseness). I use them all the time for metal work.

 

[deserteagle71]

When in a pinch I use a standard circular saw - with the blade mounted backwards to its normal direction of rotation. Works pretty darned good! Wear a face shield if using a circular saw, regardless of what blade you use.

 

[Big Barn]

48” strips...if you were nearby I would be happy to help.

 

[Aviatordave]

Holy Cow, Big Barn!! I’m experiencing extreme tool
Envy!

Got the sheet metal onto the project table yesterday. It makes a great looking top to the table. Too bad it’s going to get cut up.

 

[Big Barn]

I hope we get to see what it is you are making!