I need to cut 2 rectangular openings in an existing HVAC supply and return
How can I do this?
I've tried using a power jigsaw with a metal cutting blade -- big mess.
I see things like power shears when I do Google searches, but that seems
like a whole lot of money to spend to just cut the 2 openings.
Are there any hand tools or cutting chisels that will work for this?
Any other suggestions?
Another vote for tin snips. Quiet, safe and accurate (once you get the hang
I ended up with good ones from a the Snap-On truck that used to stop by the
place I worked, when I was doing custom car audio installations a million
years ago. If nobody here offers any specific brand names for "good ones",
Snap-On is a safe bet. http://www.snap-on.com/
On Sun, 21 Oct 2007 20:01:18 -0500, "Steve Barker LT"
Visited the HVAC parts supplies shop recently. Saw a strange 12 inch
screwdriver like tool that has a sharpened V shaped notch just behind
the 1/2 inch blade. So I asked what for and how does one use this
The tool is used to cut openings, straight lined or curved, in HVAC
sheet metal ducts. Use the front of the blade to punch a slot hole
into the metal. Hook the notch over the sheet metal. Hammer on the
flat of the screwdrivers's shaft just behind the notched part. The
notch will cut cleanly along the path of the blows.
Thanks for the youtube.com video link.
I guess tin snips it is, since that's the unanimous view. I didn't even try
them because I thought that would never work, but obviously I was mistaken.
For some reason, I was thinking that there would be no easy way to get tin
snips into the metal and cut along the line without mangling the metal.
Then I watched the video and -- DUH -- I realized that I could just make the
first entry cut in the middle of the area to be removed, and then approach
the actual cut line from an angle and do the cutting from there. I am not
usually this dense.
Make sure to get the ones with the right color handles.
There are three different types with a corresponding handle color (I don't
know what color goes with what). One that cuts in a clock wise motion one
that cuts in a counter clock wise direction and one that cut straight. Pick
the one that works the best based upon the circumstances.
Instead of tin snips ask for aviation snips. There are 3 types, one that
cuts to the right, one cuts left and one cuts stright. The handles are
usually color coded as to which way they cut.
Here is a place to look at them:
I have always called that particular tool "Aviation Snips". I thought tin
snips were the ones that look like heavy duty scissors. In a pinch I have
used BX cutters on sheet metal and they worked well except the handles are
shorter. Consequently you get less leverage with them.
Get a one inch hole saw and drill the corners out with it. Use tin
snips to cut the straight lines and finish by squaring the corners
with the snips. I've done this several times.
The hole saw will be dull after a few holes so dont expect to use it
fir your fine furniture later.
Had a humidifier installed a gazillion years ago.
the nice fellow had a metal tool with a V shape opening, he drilled a
hole in each corner, then put the v tool in and hammered it, cutting
the metal, FAST and easy, the rough edge was totally covered by the
humidifier, so appearance didnt matter
Hand tool to use is sometimes called Aviation snips, or Aircraft snips. Has
mechanical advantage to make cutting metal much easier. Don't get the long
jaws tool. Will easily handle most duct work steel.
May leave the metal rough and edges rough. Go to Automotive store, or
sears, and get auto body and fender work tools, and there are small hand
held anvils, called 'dolly blocks,' IIRC. A set of body work tools may out
of your price range.
Just went up to Sears, (which in this rare case the craftsman tool might be
OK.) they look like are starting the holiday sales with a set of aviation
snips for a reasonable price. If you go to Sears, stick with craftsman line
on this. Looks like cost will be reasonable come November. Most BORGs
carry aviation snips. I like brands: Wiss and Stanley. Have used Klein,
I make a hole in the middle of the drawn out rectangle then cut an X
out to each corner, trim the end tips off the 4 "pie shaped"
triangles, then fold them over into the duct to create a reinforced
edge and crimp the fold with Robogrip pliers all along the way. The
doubled up edge gives more material for the sheet metal screws to grab
into when you are eventually screwing on the trim grate and makes the
hole edge very strong and rigid. I'm not a sheet metal worker, maybe
others know better, but the few holes I've made came out pretty good.
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