Heat bending Cast Iron

[Harold Oney]

OK,
I need a part for my post drill ( the advancing mech.) since mine is broke. I have three that i got of E-bay but none fit (figures) i can make one of them work but it is cast iron. Can i heat the cast iron part and bend it without damaging it?


Thanks,
Harold

[beth]

i dont reckon you can - i think it will break.....

[Thomas Dean]

No, cast breaks, won't bend. If you still have the one for your drill why not repair it. Kinda hard to give a recommendation on a repair plan without a picture of the broken part but most likely it can be brazed back, that is if you have all the broken parts.

[Harold Oney]

No i dont have all the parts. I didnt think i could bend them..... so back to E-bay they go.

[arftist]

No i dont have all the parts. I didnt think i could bend them..... so back to E-bay they go.

You can't bend it but you can cut it and weld it.

[pkrankow]

How lucky do you feel? Cast can be bent, but only if it is the right particular flavor. It will break or crumble if it isn't the right type. I have cold bent old brake disks and drums something crazy (I was trying to break them, they wouldn't), I have also hot bent some parts that crumbled at higher heat. I have NOT deliberately bent known cast iron to the intended shape.

Since you have a number of examples right now, how about making a composite part out of several pieces of steel brazed or otherwise welded together.

Phil

[Timothy Miller]

Why not forge the part from steel.

[SmoothBore]

I think, in this case, "cast" iron is too general a term.

If the replacement part is cast from "grey" iron, it's crystalline structure will prevent it from bending.

But, ... if it's cast from "malleable" iron, ... well then, ... it's malleable, ... and therefore CAN be heated and bent.

( Malleable Iron is basically Grey Iron that's undergone an annealing process, to remove some of the carbon. )


It's difficult to tell the difference between cast and malleable iron, without destroying the piece in the process.

But, if the part has an area that could sustain some minor damage, without ruining it, ... you might try hammering it, to see if it breaks, ... or bends.


You might also try to "spark test" the material, and compare it to a piece of malleable iron, in that fashion.

( A forged pipe fitting is a readily available source, for a sample of malleable iron. )

[ThomasPowers]

Most of the post drills I have seen are made from the lower grades of cast iron---which is why they do break.

I'd just use steel and forge a new part and tweak to fit myself. The used cast iron cause it was cheap and easy to use not because it was best for the purpose!

[Frosty]

Ever do any casting? Cast iron will melt pretty easily in most forges. All you'd need to do is make the master, invest it burn it out and pour. Sounds Sooooo easy doesn't it? Find a couple books so you don't do anything fatally wrong and let us know how it works. And pics, we want pics!

Frosty the Lucky.

[Ten Hammers]

In specific applications, castings can be cut, placed in the approximate needed position, tack brazed and then the piece can be custom fitted to the shape you need. Then brazed fully. Many castings can be successfully migged after cutting. Sometimes heating the casting, welding and then letting cool slowly works well. Think repairing a junk vise base. Sometimes a higher nickel rod works better for this. The post heat can be done buried deep in a metal can of oil dry. Come back tomorrow to remove it. Forging another part from mild steel is absolutely a possibility but the business end and or bearing surface may not be strong enough to last too long even with a lot of oil. Yes I have taken a walk on the wild side and heated and bent a few castings but they weren't grey iron.

[Joe C B]

the "cut and weld" method will work... use stick welder /w nickle rod. I fixed the feed arm on the post drill at our Scout Camp smithy... the cam follower part of the arm was broken and missing. Welded on a chunk of steel... not pretty but has held up OK
Joe B

[Ten Hammers]

Several years ago I needed to fix the intake/exhaust manifold on the 63 pickup. Front tab was broken off. I ground the casting (which is old and not really in good shape where it broke) and got fresh metal butt joint. Cut a piece of 3/8 x 1 common bar stock for the tab. Heated the casting and tacked the repair part on with Forney x-1000 rod according to their instructions on the box. finished welding, heated the entire repair area red and put in the barrel of oil dry. Has held up for several years.

[Bentiron1946]

Blacksmiths have a tradition of jury rigging stuff and now is your time. Just think of all the fun you'll have coming up with a solution to the problem. In the past I would most likely just have made a wax model of the piece and cast a new one out of bronze to replace the broken cast iron piece. I have done that for other old machines that required new pieces for broken cast iron ones but then again I had all the casting equipment on hand. Look around and see if you can find a person who does bronze casting as a hobby and see if he can help you out, I cast pieces for others so they could get their old giant band saws up and running again. I know you can do brass in the forge and do sand casts of the old parts or make a wood pattern and make a brass casting. It's not as hard as it looks.