3/16 Cast Iron Rod

Needing some for the day job, is 3/16 (or metric equivalent) cast iron bara commercial product?

Through a scientific equipment supplier it is silly money so am looking to see if an alternative is available

25mm seems to be the smallest diameter stocked by most suppliers

If I wanted cast iron that small I would find myself an old fire grate basket and turn down some of the bars.

Rik

I seem to remember having that stuff at School, experiment to show how steel expands and contracts on cooling. A bar was heated between a couple of fixed points, a test piece of cast iron was slipped into an eye of the bar at one end and as the bar contracted on cooling, it would snap the test piece.

Can't get into scrap yards anymore, sash weights must be breathing a sigh of relief. Do you know anyone with a broken machine vice???

Regards Ian.

I've never seen 3/16" sash weights and not seen CI bar sold in smaller than 25mm

Well turn it dear Elmer dear Elmer well turn it dear Elmer dear Elmer turn it!

Ian.

Circlip,

What a heap of cast iron turnings that would create bringing a sash weight down from about 35 mm diameter to a little under 5mm while at the same time hoping it isn't full of inclusions and holds together while you are working on it.

It is a curious requirement anyway and even in sound material it will be about as fragile as egg shell in that size.

I doubt you could machine it successfully over a length beyond an inch or so. Maybe Nick's scientific supplier is quite right to charge properly for such material!

Brian

3/16" cast iron would present great difficulty in manufacture, as it would chill spectacularly and you'd end up with something ferrous that would snap if you looked at it. It would also be extremely difficult to machine. It's simply not practical to make it. Having said that, if some multi-national wanted to produce it by the mile, they'd find a way of doing it.

So I'm afraid you're going to be knee-deep in cast iron dust!

I seem to remember having that stuff at School, experiment to show how steel expands and contracts on cooling. A bar was heated between a couple of fixed points, a test piece of cast iron was slipped into an eye of the bar at one end and as the bar contracted on cooling, it would snap the test piece.

and:-

3/16" cast iron would present great difficulty in manufacture, as it would chill spectacularly and you'd end up with something ferrous that would snap if you looked at it. It would also be extremely difficult to machine. It's simply not practical to make it. Having said that, if some multi-national wanted to produce it by the mile, they'd find a way of doing it.

Is exactly what I would like to use it for, but not at £12 for 6x2" pieces

I went to a poor school, no snapping of cast iron there. We had a bar between fixed supports,with a threaded end, the strongest lad in the class would tighten the nut, after heating a slight slender girl would then come on stage and tighten the nut more with ease. You would have to pick the participant differently these day of course and do a full risk assessment due to the heat.

I remember it well,I was that lad, reined by self confidence for years. lol

Pete

p.s. now we have the whole horse to ride, can I suggest that it doesn't have to be cast iron?

The issue is that it has to be something that doesn't break according to the children's perception, so no plastic, glass or ceramic and that doesn't leave a lot that appears to be unbreakable and strong, but where there is sufficient force as the bar expands or contracts to snap the sample.

Cast iron welding rods are available in 6mm; the problem will be getting a small quantity, unless you need a box full!

Brian

I didn't realise they were cast iron - I thought they were high nickel steel

Cast iron can be welded with either a nickle filler of an S.G. iron one.

SIF seem to do S.G. iron rods in either 6 or 10mm

Hope that helps

Brian

I would expect a short length of suitably heat treated high carbon steel would fail with a suitably sudden and noisy mode of failure?

Maybe there might be a few flying fragments, safety pecs and behind a screen for them and also some for you should suffice. Care with safety is possibly one reason for the high price of basically a shear pin. Do you pour cold water over the heated bar to speed things up?🙂

Sleight of hand is a good ploy for experiments such as this - distribute rusty examples of annealed pins for some to try and break, but use a ‘hard as glass’ pin in the experiment.

I used to do the same with a challenge of catching a small rod as it fell through and out of a copper pipe. The magnet had to look like the rod.🙂

Edited By not done it yet on 28/09/2020 16:54:45

I would not have thought a SG Iron rod would break like a grey iron one.

The experiment should work with say 25mm long rod which would not be hard to turn from some sliced up larger good quality grade 260 bar

I have a large amount of cast iron welding rod (R-CI). It is about 3/16" dia. The finish is sand cast and the halve are slightly offset (mold mismatch). I don't see how they could be used for anything but welding. If you need a smooth cast iron rod I suggest you find a larger diameter and set up a hollow mill on the lathe to reduce the diameter.