how to cut a 14 inch hole

[Five Seven]

Sorry guys I have been traveling. I have an air compressor and don't mind buying additional hand tools. I am working with 18 gauge steel.

[Five Seven]

I have tin snips, angle grinder, typical hole cutters in the 4 inch range. I have been doing a bit of sheet metal work, but never large holes.

[chevynut]

Five seven, I would take your hole cutters and remove as much of the metal as you can, getting fairly close to the line. Be careful that it doesn't grab the metal and spin it, or it can be dangerous. Clamp the metal down somehow when drilling. Then I'd trim it with tin snips and finally clean it up with an angle grinder. If you don't have one, I'd suggest getting a small 90 degree air die grinder and some carbide bits for it. I use the hell out of mine and I have 4 of them. Mine are Ingersoll-Rand and they're only about $50 but you can get cheaper ones that work well at Harbor Freight.

[Custer55]

If you need something to draw your 14" circle you can make compass for large holes with a yard stick or something similar. Just make holes 7" apart in this case, 1 for a screw or pointer and the second one for a pencil, scribe or marker of your choice. With the pointer and marker points 7" apart you can make a perfect 14" dia. circle to cut to.
Brian

[Five Seven]

Thanks everyone for the input.

[NickP]

I wonder; in this instance, were one to remove up to a 1/16 or 1/32 of finished size, could one use a plunge router with a carbide bit? If you had a circle maker for it and of course if you had the router it might be a bit less work and certainly a cleaner finish - just make certain you don't try to climb cut it.

[chevynut]

I've used a carbide tipped router on aluminum but never on steel. Not sure how that would work but it might.