# Sourcing Cast Iron



## t3kboi (Mar 12, 2021)

I am going to need a few fairly chunky bits of cast Iron for a project.

I have found a lot of big CI dumbbells and kettle bells on Craigslist (far cheaper than metal shops).

Has anyone here ever tried machining these?

Also - weightlifting plates, and theatrical stage weights - both are CI and have large-ish dimensions.


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## C-Bag (Mar 12, 2021)

This has been discussed here on H-M several times but admittedly might be hard to find in a search. While you might get lucky and find something not too bad, most of those items are not cast with machinability in mind. The best stuff is Dura Bar, or grey iron or I think called CL 40. Non grey iron can be so hard as to be a challenge to carbide. Also those junk iron things can have voids and not be very pure. Depending on your project this might not be a problem but if you are wanting to make something machine grade you’d be better off finding a piece of an old junked machine to work with. I got a nice piece of Dura Bar off eBay. The machinability especially compared to some of the Chinese cast iron I’ve machined is night and day. Nice finish that doesn’t kill my carbide with no voids.


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## t3kboi (Mar 12, 2021)

Thanks!


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## JimDawson (Mar 12, 2021)

I bought some from McMaster -Carr a few weeks ago.  https://www.mcmaster.com/cast-iron


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## t3kboi (Mar 12, 2021)

I can buy from anywhere - but the question is, are the cheap/almost-free sources useable....

I can literally buy 100# of dumbbells for $20.

So - since I know what I can buy, but don't know about the  answer to my question - I guess I will get a couple of them, see how they machine, and report back...


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## Nogoingback (Mar 12, 2021)

I have no experience with dumbbells, but a number of folks here have reported they machine badly: the material is the 
cheapest garbage that can be poured into a mold.  If you have casting your own material in mind, I think a trip to the
wrecking yard would be better: lots of cylinder head etc. available and almost certainly better than dumbbells.  Another
possibility is a scrap metal place that lets you pick and choose.  If you want to buy material, an alternative to iron is
1144 stress proof.  It machines very nicely.  I've bought drops off eBay at reasonable prices.


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## benmychree (Mar 12, 2021)

Dura bar is a bit hard on the surface, but is quite fine grained and nice to machine once you get through the hard skin.


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## C-Bag (Mar 12, 2021)

There are a couple guys on YouTube that home cast their own iron and where it’s sourced and the additives along with technique are important. There’s a reason fine machine tools are made from high grade cast iron. And it’s tough to do. We see so much junk iron like in weights and old window sash weights etc where it’s not crucial because it’s not going to be machined into precision shapes where it’s porosity and super hard nature is going eat up tooling.

I’m all about cheap and repurposing but in this case you get what you pay for. I made these dogs for my shaper out of Dura Bar.


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## Mitch Alsup (Mar 12, 2021)

There are four basic types of cast iron

white iron
gray iron
ductile iron
malleable iron

White Cast Iron
          Characterized by the prevalence of carbides, impacting
          high compressive strength
          hardness
          good resistance to wear

Gray Cast Iron
          Characterized with graphite in the microstructure, giving
          good machinability
          good resistance to wear and galling

Ductile Cast Iron
          Gray iron with small amounts of magnesium and cesium which nodulates the graphite,  resulting
          high strength
          high ductility

Malleable Cast Iron
          White cast iron heat-treated to improve ductility

The question is what kind do you want ?


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## Lo-Fi (Mar 12, 2021)

Meehanite is another trade name of cast iron manufactured with machinability in mind. No voids, hard spots or even surface hardness to speak of. It's a joy to work, mess aside.


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## Weldingrod1 (Mar 12, 2021)

White iron is pure hell to cut... except with cubic boron nitride ;-)

Sent from my SM-G892A using Tapatalk


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## benmychree (Mar 12, 2021)

Meehanite is a trade name for ductile iron, when I was building steam launch engines (a 3 & 5 1/4 X 3 3/4 bore and stroke compound engine, I made the crankshafts (2 throws @90 degrees with 3 main bearings) we used 100 - 70 - 03 ductile iron, that is 100,000 lb tensile strength, 70,000 lb yield, with 3% elongation, it machined quite nicely, and ground to a polished finish; nice stuff!
Window weights were generally made of the dregs of a pour, complete with inclusions of slag, if they were made dfrom iron from pouring heavy castings, they were liable to chill and be quite hard.
Ductile needs to have generous stock left on surfaces to be machine, there is a typical defect with ductile, a pit or pucker that extends from the surface towards the interior of the casting, I allowed 1/4" of machining stock for that possibility, at the direction of the foundry.


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## C-Bag (Mar 12, 2021)

Do you think lifting plates and dumbbells are dregs too?


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## benmychree (Mar 12, 2021)

C-Bag said:


> Do you think lifting plates and dumbbells are dregs too?


They are worth a try.


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## t3kboi (Mar 12, 2021)

Thank you all!

Gray Cast, or Meehanite wouod be ideal.   some porosity is ok, perfect finish isn't really needed in my application.

My only reason for going this route is I cannot cast (no foundry, PPE, etc).  and the pieces I need are about 4"x4"x5"


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## eugene13 (Mar 12, 2021)

How about cast iron from a crankshaft?


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## nnam (Mar 12, 2021)

I would say give it a shot and you'll find out.  If you're careful, you shouldn't hurt much, at worse, you loose a bit or two.  You can buy the very cheap carbide bits and try it.  I found a few mower pieces and it cut really easy with a band saw.  Another piece I used was removed from a scroll saw's base.  The band saw cuts very easily too.  I didn't try weight piece, but I would if I want to.  The thing I am worry the most is that last time I cut cast iron, it sprays far, and covering near the chuck is not enough.  Maybe I should have cut it at very slow speed.


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## vocatexas (Mar 12, 2021)

Either Keith Rucker or Adam Booth did a video at Windy Hills Foundery last year. They said that most of his cast iron he gets from brake drums and brake rotors. Apparently he has an agreement with a local shop and buys their scrap.


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## C-Bag (Mar 12, 2021)

t3kboi said:


> the pieces I need are about 4"x4"x5"


This was the spec I was looking for. It will be interesting to see where you come up with that gig of a chunk of cast iron. There’s nothing I can think of that’s that big a chunk of cast. I think the Dura Bar I got was if I remember 2.75x2.75x4.


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## strantor (Mar 12, 2021)

I have had no luck finding a good source of cast iron chunks in dimensions like that. I've heard weights are garbage, never tried myself. Durabar is unreasonably expensive. I have a forklift I'm thinking of cutting up, maybe it will be better than weights,... probably not. And a lot of work to get it. But at least I would have chunks of usable size without having to melt & cast.


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## Joe in Oz (Mar 12, 2021)

I've used all kinds of weights like tractor weights and elevator counterweights. I found their surfaces unpredictable, but inside they were nice and grey. Go to an agricultural wrecker or tractor seller or earthmover and ask if they have any orphan front or wheel weights.

Sent from my WP5 Pro using Tapatalk


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## Tozguy (Mar 13, 2021)

I have tried two different dumbbell weights. The first one was machinable but just barely. It was impossible to cut threads in it with a tap. I did not want to use that stuff again. 
The second style of dumbbell weight that I tried machied very well. It was perfect in every way for my project. So i bought a second weight just like it for my stock pile.


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## TIM-RANEY (Mar 13, 2021)

I would 'second' Dura Bar, but it depends on the end user application. I machined a couple of ~1.5" OD pole pieces for an electromagnet from Dura Bar. It machines nicely; I mostly use WC tooling. Like any cast iron product, it's still messy.


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## ErichKeane (Mar 13, 2021)

The best source of 'good' cast iron is cheap used car parts! They are designed to be machined, and are manufactured in high quantities.  Lifting stuff is both expensive (in particular these days!), and crappy cast iron.

However, used brake rotors are basically free from most mechanics.  You can get bad/broken cast/machined crank/camshafts at most mechanics or pick and pulls.  Cast pistons are a good source of material as well, and are also dirt cheap.


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## nnam (Mar 13, 2021)

I would love to melt some cast iron.  I made a melting furnace before and gave it away during a clean up "madness".

This guy really inspire me to do it again.  In this video he melts cast iron with about a hour of burning:






In this video, he shows a bunch of good source of cast iron for melting:


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## C-Bag (Mar 13, 2021)

The problem with brake rotors is not that they are available and cheap, it’s they are not a big chunk of solid cast. Most are riddled with cooling vents and that big hole for the bearings and axel. They can be hard as can be where the pads contacted them. They are a great source of iron for recasting but the OP is not into that.


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## ErichKeane (Mar 13, 2021)

C-Bag said:


> The problem with brake rotors is not that they are available and cheap, it’s they are not a big chunk of solid cast. Most are riddled with cooling vents and that big hole for the bearings and axel. They can be hard as can be where the pads contacted them. They are a great source of iron for recasting but the OP is not into that.


Right, depending on what size you need though, the spot where the pads contact are great and about 1/4" thick. I didn't find it particularly hard though, it IS where they machine them when they are turned.


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## C-Bag (Mar 13, 2021)

ErichKeane said:


> Right, depending on what size you need though, the spot where the pads contact are great and about 1/4" thick. I didn't find it particularly hard though, it IS where they machine them when they are turned.


I guess it’s all about where you are. The only place I worked where the shop had a brake lathe was Yosemite. About 85% of the time the rotors and drums were so fried as to be scrap. And the remaining were so hard the finish was not great so I used a small pad to put a swirl pattern on them. Now rotors don’t have enough meat on them to re finish. That’s why on the local CL there are so many brake lathes that pop up when I put lathe in the search. More than metal lathes.


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## ErichKeane (Mar 13, 2021)

I've definitely seen those brake lathes  I will say that the rotors I got were from a shop specializing in diesel pickups, so likely thicker/larger than most.


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## springer (Mar 14, 2021)

What are you making that requires cast iron? I went looking for a sizable piece and found that a big chunk of 1018 or similar steel was easier to find and not unreasonable priced.


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## aliva (Mar 14, 2021)

Fork lift counter weights are usually cast. The only problem being cutting it up, arc air would most likely work best.


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## ericc (Apr 24, 2021)

I just bought a 10 pound barbell weight plate at a garage sale.  Can't go wrong for a buck.  If it is useless, I can just use it as a weight for tarps to keep them from blowing away.  Since I was curious, I decided to give it a little test to see if it was machinable.  The first picture is a cut made with a dull file.  Once it was below the skin, it cut easily.  Note the square ridge.  The skin was at most about RC 50, and the bulk below RC 30.  It filed off a familiar gray black dust.  To examine this a little further, I used a cheap hex key that I found in the street.  This is one of those shiny kinds that you often see in Ikea kits.  They are throwaway items, and they are no more than RC 50.  In fact, I wouldn't be surprised if they were RC 40 or less, since they regularly bend with cars roll over them.  Even hardened to "screaming" without tempering, they probably wouldn't last long cutting steel.  The hex key would not scratch the skin of the weight.  Shown in the same picture is a scratch on an "as-forged" piece of mild steel (a rebar stake) and a medium carbon latch from a bed frame.  The hex scratches both easily, raising a burr on the mild steel.

A decent HSS tool will probably have no problem cutting this material.  If there were any doubts, a cheap brazed carbide could be used to knock off the harder skin.


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## C-Bag (Apr 24, 2021)

I look fwd to seeing what it looks like when you machine it. Like is there hard spots or voids.


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## ericc (Apr 25, 2021)

C-Bag said:


> I look fwd to seeing what it looks like when you machine it. Like is there hard spots or voids.


So many people report them, I wouldn't be surprised if I found a few.  I'm just hoping I don't have trouble threading it.


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