how to cut a 14 inch hole

[Five Seven]

I am trying to make a fan shroud for 14 inch fans and I am not sure how to go about cutting the large holes. Is there a particular tool I should use that would work best? Thanks in advance.

[NickP]

What material? What gauge? Do you have aviation shears? Plasma Arc? Jig Saw (questionable)?

[JT56]

I think HF has different sizes lol

[WagonCrazy]

depending on the material and thickness, I would think aviation shears would do it.
aviation shears.jpg

[chevynut]

I think it would be best to know what tools and resources Five Seven has before one can answer this question. For example, to me the easiest and best way to do this would be using a CNC laser. Does he have access to one? Next would be CNC Plasma. Again, does he have access to one?

Using the tools I have I would use my manual plasma cutter and cut close to the line that I made with a large compass, dinner plate, or whatever. Then I would use my die grinder with a burr to cut close to the line, and finish with a sanding drum on my die grinder or drill press.

Without a plasma cutter I would use my die grinder and a cutting wheel to rough it out, then finish as I described.

I've never liked using any kind of snips on sheetmetal as they always roll the edge or distort the metal, and are difficult to use, imo. I have a few pairs from my aircraft mechanic days, but rarely use them.

I made these pieces for my 12" fans using the method I described. There are multiple pieces but the method would be the same if it was one. And no, it's not heavy.

[55 Rescue Dog]

An electric shear like this, is by far the best way to cut distortion free radius cuts in sheet metal. I have a milwakee with the center moving cutter, which works great on straighter cuts, but one like this is the way to go. There are cheaper knock-offs. Works similar to a Beverly shear. Otherwise, just clamp it to thin plywood, and cut it with a jig saw. Much cheaper than a CNC plasma cutter for a one off cut.
http://www.ebay.com/itm/MAKITA-JS160...sAAOSwxcRW9ffM

[567chevys]

I have used the MAKITA JS1602 Electric Metal Cutting Shear. They are nice units

Sid

[chevynut]

We still don't know what the OP has at his disposal in the way of tools and equipment. It's often cheaper to pay someone to do the work than to buy a $300 tool like an electric shear for a one-time deal.

[MP&C]

I would suggest offset snips in right and left hand. This will explain why.....

[chevynut]

Even if you use tin snips to finish the hole, you still have to rough-cut the hole out with something. You can't just plunge the snips into the sheet. Five Seven, tell us what tools you have.