Cutting 20ga galvanized sheet

[/pine]

Hey folks,

I got a project that I知 starting on that involves some 20ga galvanized steel. I haven稚 picked up the metal yet. I値l have it tomorrow, will probably start work on it this weekend.

I have to cut several pieces out of a 48肺96 sheet. All straight cuts. No curves.

I致e fabricated a lot but have very little experience with large, thin sheets. I own a set of aviation snips. Think I値l be ok with the straight snips on 20ga galvanized steel or am I asking for really sore hands?
Should I be looking at a different tool? A nibbler? I can use a grinder with a cut off wheel but I知 hoping to avoid the mess.

What痴 your experience?

-Dave

If clean straight cuts are paramount...I would take the sheet to any business that has a shear and will cut it for you...many roofing companies and heating and AC companies also have big table shears...(be sure to have a cut list)

 

[Aviatordave]

Clean and straight cuts are definitely important. I was just about to go buy a metal cutting circular saw blade until I saw Diggin It talk about the quality of the cut. Already ordered the material from the steel supplier. If I had them make all the cuts, they’d charge me an arm and a leg. I’d rather pick up a new tool that’s made for the job. Thinking hard about an air nibbler now . . . Got plenty of air in the shop.

 

[/pine]

Clean and straight cuts are definitely important. I was just about to go buy a metal cutting circular saw blade until I saw Diggin It talk about the quality of the cut. Already ordered the material from the steel supplier. If I had them make all the cuts, they壇 charge me an arm and a leg. I壇 rather pick up a new tool that痴 made for the job. Thinking hard about an air nibbler now . . . Got plenty of air in the shop.

If you are buying from a supplier they will charge you a premium for each individual custom piece...A third party capable of shearing the pieces will likely charge at a much more reasonable rate per cut... or at an hourly rate...

 

[hosspuller]

For a straight cut, circular saw blade, clamp a straight edge to the metal. For an eight foot cut, I placed the metal on the ground. (a long table would save your back) Supported the edge with a 2x4 to get blade clearance, placed the saw against the clamped guide and zipped the sheet. The edge will be sharp, run a file against it to smooth & deburr.

Any other hand tool short of a shear, will be hard to control to get a straight cut, without waves.

 

[Aviatordave]

Ahh, sounds like sage advice hosspuller. Thanks! I think I will go with the metal blade for now.

I have an 8’ table in my shop so I’ll just hang the edge over a bit and clamp it down with a straight edge. I left that workin’ on the ground stuff back with my youth when it didn’t hurt so much. ; -)

 

[Mat4644]

Swivel head shears only way to go. For roofing and siding all manufactures don't recommend circular saw and any type of blade. It messes the edges up more and more prone to rust. Been using low cost Harbor Freight electric shears for several years and they sell replacement blades.

 

[Oldpath05]

I wonder if nibblers will make a long straight cut. But maybe this or one with a diamond blade.
Straight Cutting Metal With Abrasive Discs - YouTube
Safety Guard for Angle Grinders

 

[Big Barn]

OP what is your cut piece sizes? That would have a bearing on the best route for you to take.

For an example if you needed strips 12 inch x 96 inches then definitely get it sheared.

 

[hosspuller]

Aviatordave ... Remember to support the cut off piece. Cutting on the ground meant the cut piece dropped only 1 1/2 inch. Unless it's supported, at the end of the cut, the weight will bend /distort your last few inches.

I was able to cut a 12 inch wide x 12 foot strip from 29 gauge roof metal. It was straight as the 2x4 used as a guide.

This is the blade I got:

Makita A-93815 7-1/4-Inch by 36-Teeth General Purpose Cermet-Tipped Saw Blade - Circular Saw Blades - Amazon.com

 

[Mat4644]

Using electric metal shears example. Also an air version.

Watch how easy it cuts and edge is straight and not distorted
Harbor freight electric metal shears - YouTube