Putting a 3'' Hole through 1.5'' Thick Iron in a Punch Press

[cls3277]

Does anyone have any creative ideas for putting a 3'' round or square hole through a 1.5'' thick cast iron in a punch press? The hole doesn't need to be clean or any specific size, it just needs to be large enough for a stamping to drop through it. My fallback was to chain drill it, but that is time consuming and there is not enough clearance for the drill up top, so I would have to drill it from underneath. I was thinking I would start with a pattern to start the holes and then just chain drill it with 1/4'' holes.

 

[dik]

A square hole is harder to drill <G>.

Can you use a 3" bi-metal hole saw and maybe drill from each side? They are really fast for cutting and I've used them for 1" plate.

Dik

 

[Ron]

Cast iron is not amenable to punching. It will shatter. Drilling will likely be your only recourse.

 

[MikeHalloran]

One drilled hole and a variable speed saber saw and some patience might do it.


Mike Halloran
Pembroke Pines, FL, USA

 

[JStephen]

I had to re-read that two or three times. At first, it sounded like you wanted to punch a 3" hole through 1.5" cast iron. But I gather that the hole is going to be made in a punch press frame?

Beware, you're also weakening the frame when you do that.

You can get core drills that will cut a plug, but I don't know if they're practical for your situation. Seems like the ones I've seen were shallower.

 

[Ron]

JStephen....after I read your post I went back and re-read the original...your interpretation makes more sense.

A diamond core drill will do the three-inch diameter hole. Use a concrete coring bit. You might dull the bit enough that it will be useless thereafter, so get ready for the cost of a new 3" diamond bit...about $250 US.

 

[dik]

Correction... a bi-metal blade will not do cast... a diamond core drill is likely the only way to go. Cast is too hard for a bi-metal.

Dik

 

[ToadJones]

I have cut many many cast iron pipes with bi-metal blades over the years.
What you are doing seems like it would be a real pain with a blade.

Maybe drill four holes and connect them with a blade./

 

[MiketheEngineer]

You can't punch it - it will shatter as noted. Drill, saw or flame cut??

 

[dik]

Toad... I've done 3" holes in 1" steel plate with a circle saw... much easier than cuting with a torch and smoothing... it cuts surprisingly quickly. Even smaller holes for bolts, etc. are faster to cut with a circle cutter than using a regular large diametre drill.

Dik