How can I cut extremely heavy cast iron?

Question

I want to cut up a large piece of cast iron (think storm drain cover) with thicknesses greater than 1". What would be the cheapest way to accomplish this? It doesn't have to be a fast method.

Could this be accomplished with:

• A hacksaw with a special blade?
• A 4.5-in angle grinder and then finish the job with an 8-lb sledge hammer?
• A 3-lb hammer, a cold chisel and lots of patience?

The profile of the iron is at most 3 square inches, and is relatively square. I want the cuts to be somewhat precise (I'm not just breaking it up to remove it), but they don't need to be clean.

Answer 1

If cost is the only factor, a hacksaw is hands down the cheapest option. It's also the slowest.

An angle grinder would be next up. a 4.5" with a diamond blade should do the trick, but the diamond blade will cost more than the hacksaw.

Best bet? A circular or miter saw with a metal cutting blade.

Answer 2

The angle grinder is probably going to be your best bet for making cuts in the cast iron piece. The grinder offers the best option for getting the cuts where you want them and keeping them relatively smooth.

If some of the cut locations are too deep for the grinder wheel then you may have to come at it from the back side to finish it off.

Answer 3

It is likely gray cast iron which cuts easily with a hacksaw or circular saw , or reciprocating saw, much easier than steel . (Standard hacksaw blade, start with 18 tooth ). Nodular and malleable cast irons are tougher , but still easier to cut than steel . Not likely to be white iron which would require an abrasive wheel to cut.