Cutting 6” opening in soffit

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sw_ross

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I already have wires run to the soffit locations centered over the garage door openings.
I’m planning to use the thin wafer downlights because the truss layout doesn’t allow for a recessed can housing.
The soffit material is that typical steel vented style material (not sure what it’s called).

I’m wondering the best way to cut a 6” hole in this material without crimping the edges (if I used Tin snips)?
Using a 6” hole saw scares me on this material.
I might use tin snips on the flat sections, then where there’s a corrugated divit “touch-cut” it with an angle grinder.

Any other suggestions or recommendations?
 
How many do you have to cut ? I know what you mean about a hole saw, it could grab and cause problems.
Still, that would be my preferred method but I would like to have a scrap piece to make a trial cut. You could
also use a smaller hole saw to cut starter holes for another tool.

Possibly you could use a scrap of plywood and make a 6 in. hole in it with the hole saw, to
use as a guide, if you had a way to clamp it.

A good jigsaw with a fine tooth metal cutting blade would do the job.

If you do your snip/grinder method, consider using a dremel tool instead of a grinder for the divit.
I have found them surprisingly useful with their thin metal cutting blades, such as in making a new slot on
a stripped screw head.
 
I was also thinking about using the dremel tool. I’ve used it for similar operations, it is a little more precise than a grinder.

I’m probably going to have 7 to cut in.
 
If the metal is too thin to use a hole-saw, try spinning the hole-saw in reverse. It will cut slower, but it won't snag the metal.

On How It's Made, they did that when making holes in the thin copper shell of a deep-sea diving helmet. Perfect cut, no snag.
 
Bi-metal is prob safest while using steel std black screws to reinforce the seams...$2 says reverse will work on thin (re-thin) guage. Or, at least reverse over seams.. A 6" puck light?
Of course a dremel or roto zip will work but the filings are down right nasty...
 
I like Larry's idea about trying a holesaw with reverse rotation.

Another tool would be a nibbler. A face mask would be recommended for overhead work because of all the little "niblets" it produces. Still probably not as bad as the roto zip cuttings.
 
I've used both a hole saw in reverse and a Roto Zip. The hole saw is easier to me, the Roto Zip would work better with a jig but sometimes there isn't room for it.
 
acin said:
My hvac guy has a small arc welder type cutter for holes in plenums ect
Click to expand...

Plasma cutter. You'll burn the house down if you try using that on soffit material.

I'm with the holesaw guys. And, are you sure it's steel? Unless it's very old (when was the last time you saw steel siding?) Normally it aluminum and now vinyl. Either will make your job easier.

-Hal
 
When cutting sheet metal w/ a hole saw, I always try to use a piece of wood drilled w/ that size hole to keep the drill steady.
 
So if this idea is so useful, why can't I find any negative hook angle hole saws? [I take it that would have the same effect.]

Cheers, Wayne
 
wwhitney said:
So if this idea is so useful, why can't I find any negative hook angle hole saws? [I take it that would have the same effect.]

Cheers, Wayne
Click to expand...



Likely because normal hole saws are made by the billions and thus cost a fraction of what negative hook angle ones would produced in a fraction of the quantity.
 
wwhitney said:
So if this idea is so useful, why can't I find any negative hook angle hole saws? [I take it that would have the same effect.]

Cheers, Wayne
Click to expand...
Why make one when a hole saw in reverse is the same as negative hook?
 
I think the issue is that pitch of the saw teeth (teeth per inch) of commonly available hole saws is too coarse for the thin sheet metal used in soffits. So to make due with the commonly available coarse pitch you need to reverse the rotation so the teeth efectively have a negative rake to keep the hole saw from grabbing. As was mentioned, there apparently is not enough demand to have hole saws designed for thin materials, especially given all the sizes of hole saws that there are.
 
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