Coin making?

How hard have you looked? This wasn't too difficult to dredge up via google. Crappy looking coins, but authentically crappy looking.

Ecnerwal wrote in news:LawrenceSMITH- snipped-for-privacy@news.verizon.net:

Thanks, dont know why I couldnt find something myself. Looks like fun, and looks like something I could do.

That looked interesting - but the gold coin my Dad has that is 'old' - looks like it might have been a controlled pour into a form and then struck.

So as the metal starts to cool from molten it is put into a temp form.

Otherwise the squishing look of the edge would have taken a monster press that all but melts it upon contact to do the same.

Martin

Mart> >

Cool. :)

Over on rec.knives a half dozen guys could be looking for something and the same guy would find the stuff consistanly... Bill H. Asked him how he did it and he had no real advice but got the impression it was all about trial and error and staying with it. Words and phases and more words and more phrases and then phrases and then words? ;)

Anyway, there's an AISI/SAE tool steel classification "P" and those are the industrial "coining" steels. P for press? :/

Alvin in AZ

Well it depends on what your obolus' are made of...if its pewter there is a simple way to do it and also very authentic. Have you ever noticed that a lot of pieces of eight are mistruck? that is because they used a bottom die and a hammer for the top die. Thats right, they sat the blank on the bottom die and hit it with the hammer that has the top die carved into it. use a dremel tool to carve your dies in reverse and then smack em! you can use acid to make your dies by using a magic marker for a resist but if you want a nice clear image I'd carve em...remember the dies just have to be harder than the blank so you could use mild steel and then harden them with a quench. Maybe Super Quench if you want them to last a bit longer. Good Luck!

new_CFI wrote:

They wn't harden 'with a quench' if they are mild steel - need some carbon in there ! (or case harden them)

AWEM

Well check this out then....I can make a chisel out of scrap low carbon steel then quench it in super quench and use the chisel to cut the rest of the remaining rod up into lengths...amazing stuff...do a search online for the recipe. Remember I said that it just had to be harder than the blank. Try the quench it's outstanding!

Andrew Maws> > Well it depends on what your obolus' are made of...if its pewter > there

This "Robb Gunter super quench" technique has been out there for many years now. It does work. Mild steel is not carbon-free. 1018 contains 0.18 percent carbon and A36 could go as high as 0.29. Just because folks don't consider steel below about 0.40 percent carbon to be "hardenable" doesn't mean that NOTHING happens at 0.39 So, the "super quench" simply provides a REAL fast cooling rate to get whatever it can out of the carbon that IS there. Only problem is that if you heat the super quenched tool very much, it will anneal quickly, so its not a good choice for hot work.

Type "super quench" (in quotes) into Google. I got 3700+ hits.

Pete Stanaitis

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trahern wrote:

I agree. I often make hammers out of superquenched truck axel with no tempering. Hard enough to work well, not so hard as to break. You *don't* want to superquench anything with more than 0.5% carbon, it will crack.

Watching Rob make a cold chisel out of superquenched hot rolled steel and then cold cut the parent stock with no damage to the chisel was pretty convincing.

Steve

spaco wrote:

"trahern" wrote in news:1163813562.057117.77570 @m73g2000cwd.googlegroups.com:

I don't have much experience as a blacksmith other than metal shop from high school years ago. My concern with heating the piece is that any small details where the mettle is a bit thin will be burnt off or disfigured. I suppose allowing the heat to spread down from the back would be better.

I could be thinking a quench requires it to be hotter than it needs to be.

All of your input has been appreciated.

Try uk.rec.engines.stationary (seriously!)

UK re-enactors do this fairly commonly. You shell out =A3300 to the bloke who makes the punches, then after that you're banging them out for =A30.50 - =A31.00 at the fairs. Use a sheet of pewter or silver, roughly snip it with shears, coin the impression with your dies, then trim it neatly,.

If you're serious, make your own dies. Painstaking work, but simple enough in principle.

It depends on just what you're using to heat the work. A cutting torch might fry some of the small details if you hold the flame in one spot for too long, seeing as how the flame temp is around 6000 degrees. But a gentle heat in a slow fire is no problem. Quenching usually happens around 1600 degrees (bright cherry red) for most carbon steels, so the likelyhood of losing details is not that great. Probably the biggest risk is picking the die up on the wrong surface and squishing the face with the tongs. Final hardness is a combination of factors; the specific alloy of the work, the quenching medium, the temperature of the work, the temperature of the medium, the physical speed of the quench. Some steels don't like water or brine as a quenchant. Most steels will quench in oil. Please, no automotive products. Engine oil, tranny fluid, et al, contain metallic soaps to control foaming and these can contaminate the work at temperature. Mineral or vegetable oils work quite well, and there are lots of commercial quenchants on the market cheap. If you're not sure what's in your steel, go with oil. It might miss 'full hard' by a few points of Rockwell, but you won't get tensile cracks from too fast a quench. Probably more than any other factor, carbon content in the steel determines just how hard it will get. More carbon, harder finished piece, up to a point. Any steel with at least

0.50% carbon will make a good die and harden up into the Rockwell C '50' range. For comparison, a Nicholson file is a Rockwell C 63 hardness, +/- a tenth of a point. In a dieset, hardness equates to longer tool life before the detail is deformed away. (Yeah, every stroke deforms the die a little bit, there's no such animal as the immovable object.) A good hard steel die against a soft metal like copper or silver or gold should give thousands of impressions before it gets worn out, so you should get your money's worth out of all that work.

Charly

I saw some guys striking coins at a renaissance fair many years ago. They used a rig like a guillotine with a weight the size of a bowling ball (though I don't know how much it weighed) dropping about 4 feet or so. The lower die was fixed to the base, and the upper to the weight. That way they got a nice, uniform strike every time. ISTR that they got a good coin from nearly every drop.

- ken

Myself, I think I would make two funnel shaped focusing irons. At the small diameter sits the die. The metal between and the top die placed with the top iron on - then I would smack the top die with the cannon ball...

Its massive weight is applied to the large face and it is then 'transformed' or 'focused' down to the much smaller die and like hydrolics(sp), the pressure is ratio'd upwards .

Remember - pressure can melt or weld your die to the blank, but that seems to be at a higher level than most can generate easily.

Martin

Martin H. Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder IHMSA and NRA Metallic Silhouette maker & member

Ken Rose wrote: