Expanding a hole

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Bob Mears

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Sep 1, 2004
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I have a 2" hole in my instrument panel that I need to be a 3" hole. Is there a trick to make this a nice looking round hole other than just cutting and grinding?
 

RonL

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Jan 9, 2007
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I have a 2" hole in my instrument panel that I need to be a 3" hole. Is there a trick to make this a nice looking round hole other than just cutting and grinding?
If you have the right tools already, that is good, if not find a hole saw 2-1/4" and drill a wood blank and taper it so that it centers in the 2" hole, then using the drilled center hole (1/4") as a guide, chuck a 3" hole saw and drill out the larger hole.:)

All the box stores carry a large selection of sizes these days.
 

Hot Wings

Grumpy Cynic
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I'm assuming this is an aluminum panel? If so I see 2 options. The best being a hole punch of the right size. You probably don't have one.

The second is to rivet a piece of scrap aluminum to the existing hole with the rivets inside the 3 inch dimension. Behind is best and you can use thin wood as a substitute. I've used double stick foam tape also. Then simply cut with a conventional hole saw of the correct size.

If this is going to be done in place keep in mind that the riveted parts are going to start flying around after the panel is cut. Not so much of a problem with the tape.

Make a test cut with any hole saw you haven't used before. The all tend to make holes larger than stated.
 

Joe Fisher

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Feb 10, 2007
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Galesburg, KS South east Kansas
I would clamp a over size peace of 1/2" plywood to the panel. Find the center of the 2" hole and drill a 1/4" hole. Then put a 1/4" inch bolt on the 3" hole saw to guide the saw.
 
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