Cutting 20ga galvanized sheet

[Aviatordave]

Hey folks,

I got a project that I’m starting on that involves some 20ga galvanized steel. I haven’t picked up the metal yet. I’ll have it tomorrow, will probably start work on it this weekend.

I have to cut several pieces out of a 48”x96” sheet. All straight cuts. No curves.

I’ve fabricated a lot but have very little experience with large, thin sheets. I own a set of aviation snips. Think I’ll 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’m hoping to avoid the mess.

What’s your experience?

-Dave

 

[Industrial Toys]

I find that snips really bugger up the material. They are my last choice for any kind of cutting.

Air nibbler good for light material but makes a mess with a million little bits. Also, wide curf.

Jig saw good (I have a worm drive saw) but SLOW and not terribly accurate.

PLASMA, Good, but will make ugly smoke on galvanized. And turn material edges yellow. Also, I can never do anything good with PLASMA. Just nice cuts, when it doesn't matter.

Metal cutting Circ Saw Blade. Never tried. Probably good for straight cuts.

 

[hosspuller]

I use a metal carbide tipped metal cutting blade in a circular saw for metal roofing. It will work for your project. Do confirm it's a metal cutting blade. Wear eye and ear protection. The blade throws little bits of metal. It's fast and cool. unlike an abrasive blade.

 

[newbury]

I've just finished cutting a several roofing panels and I've done other cutting on thin flat steel.
Tools used:
Snips - ok if you have superman hands
Nibbler - great if you have superman hands
Air Nibbler - don't have but would probably do good, but let the chips fly
HF 14 Gauge 4 Amp Heavy Duty Metal Shears - GREAT if metal is flat, corrugated not so good
Angle grinder with a thin blade - very good but I had difficulty following a line and LOTS of sparks
Reciprocating saw w/ good metal cutting blade - Excellent but material needed to be clamped tightly
Jigsaw - couldn't find a special blade, but pretty good for flat metal. Again clamp tightly.
Circular saw w/ special blade - good but threw a lot of small metal pieces.

For your purpose I'd try the Heavy Duty Metal Shears (~$50), if not that then the Air nibbler (if you have one). then the Jigsaw.

 

[fried1765]

I find that snips really bugger up the material. They are my last choice for any kind of cutting.

Air nibbler good for light material but makes a mess with a million little bits. Also, wide curf.

Jig saw good (I have a worm drive saw) but SLOW and not terribly accurate.

PLASMA, Good, but will make ugly smoke on galvanized. And turn material edges yellow. Also, I can never do anything good with PLASMA. Just nice cuts, when it doesn't matter.

Metal cutting Circ Saw Blade. Never tried. Probably good for straight cuts.

YUP!
Metal cutting circular saw blade.

I have both the heavy duty shears and a nibbler, and I would not use either.
The 7-1/4" metal cutting saw blade is perfect for straight cuts.
Wear eye and hearing protection

 

[Diggin It]

I've made quite a few cuts with the snips in the first picture here: https://www.tractorbynet.com/forums/projects/420035-tool-time-tbn-post5597652.html#post5597652

The angle of the handles and the size of the grips cut out the hand stress and fatigue considerably. I've been able to make straight cuts across ribbed roof panels with little trouble. No chips, no sparks, no noise.

 

[MF RED in MT]

Hey folks,

I got a project that I’m starting on that involves some 20ga galvanized steel. I haven’t picked up the metal yet. I’ll have it tomorrow, will probably start work on it this weekend.

I have to cut several pieces out of a 48”x96” sheet. All straight cuts. No curves.

I’ve fabricated a lot but have very little experience with large, thin sheets. I own a set of aviation snips. Think I’ll 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’m hoping to avoid the mess.

What’s your experience?

-Dave

If it were me I treat myself to a new electric tool for $44 or maybe a cordless one for more $$$...

KC

Here's a link to 1 of these metal shears:

https://www.homedepot.com/p/WEN-4-A...ivel-Head-Electric-Metal-Shear-3650/300676586

Now if it was near my birthday, this is what I would choose:

Milwaukee 2635-2 M18 18V Cordless 18 Gauge Double Cut Shear

 

[fried1765]

I've made quite a few cuts with the snips in the first picture here: https://www.tractorbynet.com/forums/projects/420035-tool-time-tbn-post5597652.html#post5597652

The angle of the handles and the size of the grips cut out the hand stress and fatigue considerably. I've been able to make straight cuts across ribbed roof panels with little trouble. No chips, no sparks, no noise.

Some tools (7-1/4"metal cutting saw Blade) are simply better for specific jobs.
I'll bet that you would not use a battery powered grease gun either.

 

[Diggin It]

I used a circular saw for many of the panels. It left a very ragged edge, quite capable of tearing skin.


And no, I don't see a need for a battery grease gun.

 

[Big Barn]

Depending on the piece sizes, have your supplier shear as much for you as possible.

 

[/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