Sounds simple - how do I cut a neat 1" round hole into hot air duct? Its flimsy and I can't get behind it easily. I don't have an air nibler either, and would rather not buy one if possible.
Thanks!
Dean
Cut a 1" round hole in galv duct?
Jan 17, 2006
12 Replies
Bi-metal hole saw.
R
Borrow or rent a knockout punch tool. The kind used for electrical work. Greenlee makes one.
why do you want the hole?
drill a ring of 1/8 inch holes in a circle and use the drill or a dremel tool to finish it.
I would (and have) cheap hand nibbler from Radio Shack.
That assumes he can get his hand inside the duct.
Use a 1" hole saw. Here's a (lousy) picture of one:
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If the link's broken, go to
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and search for "hole saw". You also need an arbor. The arbor holds a 1/4" pilot bit which sticks out maybe
1/2" ahead of the cylindrical hole saw. The whole setup will cost you about $25. If you get the right arbor, it'll be usable with a variety of hole saw sizes.
I just assumed that he was going to put something through the hole, but you're right.
I was concerned he might be planning to put a electrical cable in the duct, a bad idea.
It was for a thermostat probe on a wood furnace. I drilled a small hole and then enlarged it with an irwin unibit. It was perfect!
(Sorry, I forgot I had that drill!)
Dean
Those Greenlee punches are really cool, though. :-)
Picky picky picky. What's so bad about putting a wire through a sharp-edged hole, into an environment where it might be at least dried out by heat, or maybe melted? You worry too much. :-)
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