Knockout for 5 inch

[patricknola]

Hey Guys, I've got I stall 2 junction boxes tomorrow for 5 inch pvc. I don't have a 5 inch knockout punch, I've got a 5 1/2 inch hole saw coming but it might be held up. Does anyone have a tip on how to knockout (3) 5 1/2 inch holes in metal junction boxes? TIA.

 

[hillbilly1]

I have done it with a jig saw with metal cutting blades. Just draw a circle of that size, drill a starting hole, and let the saw beat you to death! LOL!

 

[AC\DC]

Dremal with a high speed metal bit.

 

[LarryFine]

I bet your local orange or blue store has them on the shelf.

 

[kwired]

Punch two 2-1/2 inch holes per 5 inch conduit.

2.5 + 2.5 = 5, right

5.5 inches is getting large enough it won't be too tight of a turn for a jig saw or reciprocating saw if using a narrow scroll type blade like it would be for only a inch to 2.5 inch hole.

Plasma cutters make cleaner cuts, especially with someone experienced using them, than a torch typically does, just a thought.

That large of a hole saw not always so easy to handle with hand held drill either. I drilled several 6 inch holes in some metal plates one time - something like 40 of them. I made jig to set up in a drill press to do those.

 

[hillbilly1]

Punch two 2-1/2 inch holes per 5 inch conduit.

2.5 + 2.5 = 5, right

5.5 inches is getting large enough it won't be too tight of a turn for a jig saw or reciprocating saw if using a narrow scroll type blade like it would be for only a inch to 2.5 inch hole.

Plasma cutters make cleaner cuts, especially with someone experienced using them, than a torch typically does, just a thought.

That large of a hole saw not always so easy to handle with hand held drill either. I drilled several 6 inch holes in some metal plates one time - something like 40 of them. I made jig to set up in a drill press to do those.

Something like post #2? LOL!

 

[kwired]

Something like post #2? LOL!

yes. but if you use a narrower scroll type blade it shouldn't beat you to death as easily. Most of that comes from turning too sharp with a wide blade.

 

[chicken12]

Home depots normally stock 5" and 6" hole saws in most stores while the 5-1/2" are special order. Maybe grab a 5" and grind out the hole a little bigger if you cannot wait. Good luck

 

[Chamuit]

And you've got to show us the ugly after pictures.

 

[LarryFine]

Maybe grab a 5" and grind out the hole a little bigger if you cannot wait.

If he then cuts a slit and bends the edges apart, he could probably screw the MA in.