Cast Iron?

[craze8t8]

I got an old cast iron nineteenth century window weight. Put my band saw to it; hardly scratched the surface.Tried some carbine on it. The finish is horrible. Anybody have this problem?

 

[JerryK]

Even the the early 1960s , some Cast Iron had many impurities.
Hard spots, like hitting a ball bearing while machining.
Sometimes the only way was grinding

Probably even worse condition in the 19th century
Good luck
JerryK

 

[4GSR]

Your window weight was probably chilled too fast causing the surface of the cast to be hard. And depending on the material mix when it was poured, it could have created "white metal". If so, not much you can do to it other than use it as an window weight. If you have a BBQ pit, get a hot fire going in it with charcoal, lay the window weight in the coals and cover with more charcoal. Come back in a day or so when the coals are gone and it is cooled off. Then try to cut on it again. If no luck, toss it. Might make a good boat anchor. Ken

 

[hermetic]

agree with all of the above, and will just add be prepared to toss it, because window weights were sometimes, but not always, made from the old crap stuck to the bottom of the crucible at the end of every pour. It may not be worth the tooling you might wreck on it!

 

[EmilioG]

edit: deleted

 

[hermetic]

Pour it yourself? I am in the UK, and it is available from most steel stockholders. Not cheap, but completely at the other end of the quality scale to window weights. There are some good window weights, can you go to a local scrapyard and go through a pile till you find some decent ones, good indication is to break one in half and look at the grain and colour. Try a file too. Chilled cast iron is as hard as the hobbes of hell, and was used for the rolling mill rollers in steelworks, and low quality window weights will have slag and crap inclusions in them, because they didnt bother to hold the slag back when making them. You could make a cupola furnace and have molten cast iron in 30-40 minutes, after the time it takes to build the furnace!

 

[benmychree]

Yes, hermetic is correct; foundries that used cupola furnaces used the leftovers for window weights, they would have a number of molds ready to use up the overage that remained from the regular run of molds to be poured, and there was no need to eliminate slag or worry about chilled metal; if metal intended for heavy castings is poured in thinner sections it tends to chill; if metal for thin castings is poured to heavy castings, excessive shrink and cracking can result. I did a little business with an iron foundry in Petaluma Ca. (long gone), their crap metal went to salmon fishing weights, iron balls about 2 1/2" diameter with a wire loop; as soon as a fish was hooked the weight would be released and drop to the bottom of the ocean, so quality was not of concern.

 

[Terrywerm]

If you are looking for a source of decent gray cast iron, McMaster-Carr carries various sizes and shapes. What they are probably selling is Dura-Bar, which is a continually cast type of iron bar. I've done some work with Dura-Bar, but we had to send it out to a heat treat company to be normalized before we could utilize it.