Cast Iron

[jolijar]

I have plans for a glow engine that uses cast iron for the piston. Where can I buy cast iron (I need about 8" of 3/4" Round) Or is there a substitute I could use?

 

[Deanofid]

What Pat posted. Speedy Metals is a good place.

Dean

 

[Tin Falcon]

here
http://www.mcmaster.com/#iron-bars/=8pl5zu
I buy metal here if in the area or can have it over night at ups ground rate.

 

[bearcar1]

I have had very good service from metal express for my cast iron needs.
metalexpress.net


BC1
Jim

 

[GWRdriver]

For a small weight like this I suppose anyone will do but for future reference, when I have needed a larger quantity of C.I. material (like a slab of grade 40 1" x 4" x 16") I shopped the net and found substantial savings over the usual suspects.

 

[rickharris]

Small lumps - try to find some old sash windows the weights were cast iron - A plastic installer window may be able to help.

For bigger lumps Tractor weights.

 

[Tin Falcon]

I read an article somewhere IIRC HSM magazine or a book they publish that suggests using cast iron plumbing fittings a pipe cap for a piston a coupler for a sleeve. have not tried it but should be a common item and save some machining time just a thought.
OK found the 1 page tip, in Projects in metal book one pg 28, reprints from the first two years of PIM magazine. anyway the article recommends pipe plugs from the local hardware store as a source for small pieces of CI. these can be used for pistons rings eccentrics and cross heads according to the author.
This was written 20 years ago before the advent of the big box Home improvement store in a town of any size and mass chinese imports but IMHO worth a try.
Tin

 

[shred]

Sash weights and barbell weights are about the lowest possible quality CI, but frequently good pieces can be had from them.

 

[toolsrul]

Do a Dura Bar search. Good stuff & consistent in machinability.

 

[GWRdriver]

Old sash weights, really old ones, were generally decent iron but the problem is they were often cooled too quickly and are chilled and hard, but some weren't. I've had some good ones and annealing will usually soften the hard ones up but as Tin says current barbell weights tend to be garbage and the more recent the production the worse they are.

 

[winklmj]

Small lumps - try to find some old sash windows the weights were cast iron - A plastic installer window may be able to help.

For bigger lumps Tractor weights.

These are gonna be hit or miss. I snagged 3 the other day at the scrap yard. They are cast iron but 1/8" in they seem like they are hardened. My little 4x6 bandsaw stopped cutting. I'm gonna toss 'em in the fireplace and try and anealing them otherwise they're gonna be useless.

Heard the same can be true for the tractor weights but you may get lucky and come up with some nice useable pieces.

 

[itowbig]

car engine. a crank shaft from same

 

[Artie]

car engine. a crank shaft from same

I hadnt thought of this, once a crank has wrecked a journal its useless and also worthless, taking them away from the engine machining place would be welcome from their point of view.

One thought, cranks are usually nodular cast iron. Most of the stuff Ive bought from metal supply houses in past is spun cast and therefore a different grain structure and the carbon content on cranks seems a whole heap less while they seem pretty hard. Is this a problem? Anyone had any experience? Im off to grab a crank sometime today to play with. :big:

 

[tel]

Sash weights and barbell weights are about the lowest possible quality CI, but frequently good pieces can be had from them.

Might be different there, but I've used dozens of the things and all but one have been excellent iron, the one 'bad' one was still good iron, but badly chilled and hard to work.

 

[bearcar1]

Im off to grab a crank sometime today to play with. :big:

EEeeewwwww! Artie, that's WAYYYYY too much information. And a blighter your age. Ever thought of therapy? :big: :big: :big:

BTW, don't forget to wash your hands afterward.


BC1
Jim

 

[bentprop]

There's an easy way to check if a sash weight is going to be of any use.
You give it a good whack on a hard surface to break it in half.If the inside is a nice matt shade,it's fine.If you have glistening pieces though,forget it.That's sand,which will q uickly ruin your cutting tool.I think Bogs gave that tip in his paddleducks build IIRC.

 

[Cbowler]

I'm thinking about building a 2-stroke glow myself, for my next project, but what I've been pondering is- "Is cast Iron really necessary - unless the engine is going to see a lot of service perhaps not?".
Cole

 

[bentprop]

Is cast Iron really necessary - unless the engine is going to see a lot of service perhaps not?".

I would think hard aluminium alloy is probably better.That's what all the manufacturers of model 2-stroke engines use,and they last an amazingly long time,even when abused by dimwits not putting enough oil in their fuel.Unfortunately,those sort of grades of alloy are not normally available in small quantities,which is possibly one of the main reasons for specifying cast iron.Although for our sort of use,you can probably get away with 6061,which is quite easily sourced.my 0.02.

 

[Artie]

EEeeewwwww! Artie, that's WAYYYYY too much information. And a blighter your age. Ever thought of therapy? :big: :big: :big:

BTW, don't forget to wash your hands afterward.


BC1
Jim

Ooooooohhhm Jim....I ALWAYS wash my hands.......

I got my hands on a broken crank and stuffed it into the power hacksaw.... I didnt stay around to watch it just got on with other stuff.... then I pressed off the cam drive grear and placed it into the lathe..... whoa! That aint cast iron...damned hard forged steel...... doh *bang*

As you can see it was all rusty so it was hard to tell....

I should have looked harder..in the last pic of the thing in the hacksaw you can see the "seam", this is called the "parting line" and in cast cranks its very thin, as per the 2 halves of a mold meeting. In a forged crank it is very wide as in this example here..... it was very obvious after I went "What the ...??"

Ill try again.... dont forget these things have holes drilled all through them, thats why I went for a large crank and used the snout.... itll make a great press tool....

Cheers all

R

 

[Blogwitch]

Just getting back to sash weights as a source for cast iron.

I have been using them for many years, and there is a bit of a technique to making it easier on your machinery.

Normal sash weights are cast with the hanging loop downwards, so all the dross and crap rises to the end opposite. I cut off about 3" at that dross end and discard what has been cut off, and most times, all the rubbish is then gone. Don't try cutting it with your bench tools, the hard skin formed over maybe the last century or even more will really test your cutting tools. I, using a small angle grinder, just score around the bar where I want the break, then just dropping it onto a concrete floor will cause it to break around the grind line, or maybe persuade it to break with a lump hammer. All safety rules should be applied. Using this method, I break them up into manageable billets of between 2" and 6" long, depending what it is required for.

Next comes to getting thru the hard outer skin on the lathe. You DON'T cut thru it, you get under it, and peel the skin off. I find that putting a cut on of anything up to 0.100" will get under the skin (it depends how misaligned the moulds were when they were cast) and you will be left with a nice machining, very tight grain, cast iron bar. I usually get a minimum of 13" long by 11/8" diameter, sometime a lot more. In cost terms, that would work out to almost 20 squid from a metal supplier, my usual cost is 30 pence each from the scrap yard, plus a little work getting it out of the rough. To me, at those sorts of prices, it is time well spent.

I suppose the quality does rely on where in the world you come from, and even the area you live in. Being very close to the Black Country in the UK almost guarantees I will get the best quality ones ever made. That is where it all started a few centuries ago.

Bogs