cutting (?) cast iron

[Michael Ginsberg]

Strange situation.... I have to cut a chunk out of an old lathe bed that is cast iron. I need to give it to a friend to extend his lathe bed by one foot. He makes walking sticks for disabled vets. I am not a metal worker... so I have no idea on how to do this. Can I score it with my hand held grinder or a carbide tipped sawzall blade and give it a hit w/ a hammer? The cast iron is about 1/4 inch to 1/2 inch thick. It does not have to be a pretty or clean break. I can smoothe it on the grinder afterwards. The chunk of lathe bed is not going to be actually attached to the other bed, just attached to the bench in line with the other.
Thank you all...
Michael

[Dan Hintz]

Break lines won't work (no crystalline fracture line)... sorry to say, you gotta cut this bad boy the entire way.

[Mike Hollingsworth]

Cast Iron is very soft.
GLWT

[ray hampton]

why not cut it with a sawzall ? why can't your friend use the bed without cutting it ?

[Michael Ginsberg]

Ray,
Space limitations. No room for the full 40" bed I have. As far as the Sawzall goes... What kind of blade should I use? Bimetal blade? Carbide?
I am sorry...I am clueless with this....

[Dan Hintz]

They make Sawzall blades specifically for cast iron, but any metal blade will do it. I prefer rotary diamond blades and let my cut off tool handle it for big items...

[Steve Ryan]

I have done some heavy CI cutting with just a reg bi metal blade. Be patient, the saw will do its job.

[Michael Ginsberg]

Thank you. will try the blade. did you lube? Oil -water?

[Scott T Smith]

No lube is necessary; CI is self lubricating.

A porta-band would be my first choice, easiest to use and cleanest cut. A sawzall would be the second choice.

[ray hampton]

a metal -cutting blade should work fine, if you use a lube, will it help to keep the saw dust from the cast iron from flying all over the place

[Chris Fournier]

I'd prefer to use an abrasive cuttoff blade over the sawzall as I think that it would do a tidier job as long as the operator was a skilled pilot!

[ray hampton]

will the abrasive saw cut all of the way thru. this piece ?

[Michael Ginsberg]

Chris,
Do you mean a blade for my circular saw or angle grinder? Please keep in mind I am cutting a lathe bed that is about 6 inches wide, 3 inches high, and apprx 3/8 thick...

[ray hampton]

Chris,
Do you mean a blade for my circular saw or angle grinder? Please keep in mind I am cutting a lathe bed that is about 6 inches wide, 3 inches high, and apprx 3/8 thick...

abrasive blades are good at breaking into pieces [at least in my experience ]and will break when use in a cut-off saw, I doubt that we could hold the circular saw steady enough to cut this lathe bed, a angle grinder wheel is thick enough that it may not break

[kelly logan]

Use a circularly saw with abrasive blade, a 2x6 as a guild and set saw to lightly grind a grove and every pass set the depth a little deeper. The deeper the cut per pass puts extra pressure on blade that’s why you take light passes.