Diy knockout holes

[bluedog225]

I’m needing to put some holes in a metal cabinet to run electrical in and out for my solar inverter, battery, etc. I’d like to use push through bushings or clamp connectors.

Thought I could use a step step dill. I didn’t realize knockout holes are a unique size.

I see several knockout punches in kits saying “1/2 in. , 3/4 in. , 1 in. and 1-1/4 in.”

Are these the actual size or are they shorthand for the actual size below?

Obviously I’m new to this.

Thanks

 

[metlmunchr]

The sizes on the kits are the nominal sizes of the pipe the punches will punch holes for.

 

[OccupantRJ]

Harbor Freight step bits have at least two of the electrical sizes in their step bits as I have used them as such often. They have two sets of bits available.

 

[ycgoat]

When using a step bit, I sneak up on the hole size, checking my connector as I get close the hole size. Hole saws would be cheaper than a knockout set or step bit

 

[LXCam]

Those are the actual sizes of the holes. Electrical conduit is listed by the ID (inside diameter). Those are the sizes needed for the fittings

 

[gungatim]

HF has a nice inexpensive set of knockout dies. That's what I use on thin sheet metal. Drilling large holes ends up denting and leaving burs. Much cleaner to use a die.

 

[dogdog]

Knock out hole size is what you wanted to drill for the conduit size…

It dependents in your situation… I have used large drill bits 7/8, a knockout punch when I find one. And have that HF hydraulic unit as well. The hydraulic unit is fine, the punches are a bit cheese. Will work fine.

The new thing now is those carbide tooth bits. Klein ones are nice but super expensive. Amazon/ebay tct would work few threads on this.

If I were to used it on live circuits where the metal shaving will get into electrical. I use knockout punches. Anything else I would just do anything I get my hands on. Was kinda scary drilling around live electrical panels last time.

 

[dogdog]

I see several knockout punches in kits saying “1/2 in. , 3/4 in. , 1 in. and 1-1/4 in.”

Are these the actual size or are they shorthand for the actual size below?

The marking of 1/2 1” etc on the Knockout punches are for the conduit size. The actual hole diameter is the knockout hole size in your chart. Or close to those knockout hole size. That is true for electrical knockout punches. If you buy ones for sink holes…. It will be different.

 

[reader2580]

I've used a cheap set of two step bits bought at Menards for around $20. I just keep drilling a step bigger until the fitting finally fit. This isn't plumbing where you are making connections that have to hold water. A slightly bigger hole rarely matters.

 

[bluedog225]

The step bits get a little large for 3/4 conduit fitting knockouts. And it does make a mess in my cabinet.

And I needed an excuse to buy a set of knockout punches.

Thanks all.

 

[OccupantRJ]

Step bits come in a lot of different steps, diameters, and reaches. These are mine.

 

[Norcal]

You have 4 choices, 1) knockout punches (my preferred choice), 2) carbide hole saws (2nd choice), 3) hole saws,4) step drills, Unibits®. Any one of the choices will work, some will have cleaner results then others, the holes saws are a bit rough compared to the others.

 

[oldmachinenut]

HF has a nice inexpensive set of knockout dies. That's what I use on thin sheet metal. Drilling large holes ends up denting and leaving burs. Much cleaner to use a die.

I used my Harbor Freight knock-out punch to make the lower rack holding the strap wrench, reamer and pipe wrench. It easily punched through the 1/8” angle iron.

 

[billconner]

I've had Green Lee - 1/2 3/4 and 1 - for a long time. No regrets. Very clean, easy, and easy to be precise in location.

 

[sparky 1971]

1/2" conduit uses a 7/8 hole, 3/4" requires 1-1/8" and 1" needs a 1-3/8" hole. I use size specific carbide cutters, but used step drills for years, and still do when I need to increase a hole from 1/2 to 3/4 or 3/4 to 1. The hydraulic knockout set comes out for anything larger than 2" up to 4".

 

[OccupantRJ]

I got curious a few years back and tried my battery impact on my Greenlee knockout set. Yea baby! A bit of grease on the pull bolt and that sucker flew through the box.

 

[rkevins]

I have drilled tons of holes in electrical boxes with hole saws Sparky 1971 has the sizes

 

[Crazyjake8493]

Every step bit I own has 7/8", 1-1/8", and 1-3/8" holes for 1/2", 3/4", and 1" conduit knockouts. 95% of the time I drill a pilot hole and use a Greenlee knockout punch for an easier and cleaner hole. Harbor Freight has a cheap kit that should do up to 1-1/4" conduit I believe.

 

[reader2580]

A friend of mine who was an electrician working on big stuff gave me a set of Greenlee hole saws designed for conduit up to 4". He also gave me a big Craftsman drill from the 70s. I swear that drill with a hole saw could snap your wrist if the hole saw gets stuck.

 

[rabidsquirrel]

WTF is 6/3"? That chart seems like an AI poorly generated search result...

 

[bluedog225]

Yeah. That’s why I never tell people to Google something. Google is a propaganda and advertising machine. It’s a thousand times better to ask you guys.