Ok to make a panel knockout bigger?

You could spring 25 bucks for a set of these punches.

I've had them for years and they've helped in tight spots.

Jeff

I have screw drive KO punches, and recently sprung for a hydraulic set. That's the way to do it. Hole saw is not my first choice.

These look like they go up to 1 1/4 I think the outside diameter of a

1 1/4 conduit fittign is 1 1/2? How do these work? I have limited acess as this panel is inside a drywall wall.

stryped fired this volley in news:bd5ea59a-b203-47c3- snipped-for-privacy@s20g2000yqd.googlegroups.com:

You'd have better access if you chopped out a section of the rock and repaired it after the electrical work was done.

It might take less time than all the fiddling you'll be attempting from inside the box.

LLoyd

So I got off my arse and went downstairs and dug out my set and an. Same as the one in the link I gave you.

The largest punch measures 1-5/8" diameter.

Capice?

If you're anywhere near Red Sox Territory I'd be happy to loan you that punch, it probably wouldn't be worth your wasting postage mailing it back and forth between us though.

Good Luck

Jeff

And be safer.

You'll have quite a time enlarging a 1" hole to 1 1/4" with a hole saw.

How did you plan to keep it centered?

As far as hole size, you'd have to check your local code(s).

Anyway, as far as enlarging the hole, I'd probably use my nibbler or borrow one of those punches that jeff_wisnia pointed out.

Or a step drill:

Have Fun! Rich

I have one of those and planed on using it. It only goes up to 1 3/8. Then planed to use a 1 1/2 inch hole saw with a block of wood covering the hole.

Not hard to do, actually.

Clamp a backer board to the box to steady the pilot drill.

Or, even better, get one of Starrett's Oops Arbors. It's an arbor that takes two hole saw blades, one slightly ahead of the other. The smaller one in front serves as a pilot, the one in the rear cuts the hole to the new size.

John Martin

Get a step drill bit. They're very useful for sheet metal work where a hole punch isn't practical.

Mark Rand RTFM

Up to 1 3/8" diameter

Gunner

"Aren't cats Libertarian? They just want to be left alone. I think our dog is a Democrat, as he is always looking for a handout" Unknown Usnet Poster

Heh, heh, I'm pretty sure my dog is a liberal - he has no balls. Keyton

My personal policy is to hit "Ignore Thread" whenever I see "stryped".

I hope he doesn't wind up missing in action after an electrical escapade.

Pete Keillor

On Wed, 02 Dec 2009 22:04:15 -0500, the infamous jeff_wisnia scrawled the following:

Oh, Crom! I bought one of those and it stripped out before I even got white knuckles on the wrenches, Jeff. I immediately returned it and found a replacement (pair, 1.5 and 2" with leather case) on eBay for about the same price. I think that if I'd put the threaded die on the bolt and spun it, it would have travelled all the way down the screw without stopping or slowing. It was that loose. Well, it would have done that before it stripped right out on me...

That particular HF set gives real cause to RUN AWAY!

-- Follow the path of the unsafe, independent thinker. Expose your ideas to the dangers of controversy. Speak your mind and fear less the label of 'crackpot' than the stigma of conformity. And on issues that seem important to you, stand up and be counted at any cost. -- Thomas J. Watson

On Thu, 3 Dec 2009 13:28:13 -0800 (PST), the infamous John Martin scrawled the following:

What does Starrett offer for use to go the opposite way, when you've drilled a too-large hole?

-- Follow the path of the unsafe, independent thinker. Expose your ideas to the dangers of controversy. Speak your mind and fear less the label of 'crackpot' than the stigma of conformity. And on issues that seem important to you, stand up and be counted at any cost. -- Thomas J. Watson

=A0 =A0 =A0 =A0 =A0 =A0 =A0 -- Thomas J. Watson- Hide quoted text -

Ground flat stock, Larry, so you can start over.

John Martin

If you can find them, the step drills are good for that sort of thing. The previous size acts as a pilot for the next larger size.

I've only used mine a few times, but they seem to work OK. The problem is that you paid full price, instead of waiting till they were on sale for $15. :)