Struck Coin Blanks ???

Every since watching a woman dressed in pirate garb at a renaissance fair (or faire if you prefer) place a blank in a set of dies and drop a heavy weight on it to strike a souvenir coin I have had in the back of my mind the idea to strike my own coins. I can certainly make the dies. 4140 is relatively easy to machine if you know how, and it will harden "hard enough" for a low production number of from a few hundred to a couple thousand coins. I also keep a bit of O1 and W1 on hand for those cutting tools I can't hand grind from HSS or carbide. I even have a propane forge in the back along with a toaster oven for tempering (although it gets used more for powder coating).

I started writing with two questions in mind.

Where to buy/make coin blanks at the best price? Not the 10-20 on Ebay or Amazon, but a couple hundred to a couple thousand at a more reasonable bulk price.

I forgot the other question, so my second question is what question (or questions) did I forget to ask? Maybe what alloy would best? I suspect an annealed copper alloy of some kind. Many an amusement facility used to have a machine that would take your penny (and a dollar) and roll your penny into a souvenir key tag back in the days when pennies were still copper.

I am aware. I've actually spent a bit of time researching them already. I have seen over priced blanks on the eCommerce flea markets as indicated already, and I have found plenty of people selling coins, but I have not found what I am looking for.

Many country fair coins were made of soft aluminum.

Maybe the brass sold for stamped dataplates or tags?

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Probably the alloy used for copper pennys can be got.

Hobby stores may have coin-making supplies.

Early Chinese coins were lost-wax cast from bronze.

Joe

That's not a bad start. Unfortunately they also sell end product which usually means they don't sell for real wholesale pricing. Its still a good idea.

Getting actual penny copper is not a horrible idea. I could certainly do some experiments by going through my change bowl and sorting out the older real copper pennies to be restamped. I suppose the zinc pennies stamp okay, but they may not re-stamp okay. My end goal is mostly for a coin "about" the diameter and thickness of a regular classic silver dollar.

Casting copper from old pennies, motors, etc could also be an option, but that would make it a whole different class of project. A time and money thing, and I don't mean the pennies. Also, my little propane forge probably isn't up to melting enough copper to be worth while. Its fine for one off heat treating projects, but probably not for casting any quantity.

Hmmmmm... I suppose its worth a look to see if Michael's (are they still in business) or Hobby Lobby has anything. At the very least I could read the packaging if they do to see if that generates an other leads.

I don't think casting is really the way I want to go.

Maybe ask non-ferrous scrap buyers if they'll sell knockouts (donut holes) from punched parts for a little over scrap price?

hth,

bob prohaska

Do your own "fineblanking" - stamp your blanks from aluminum, copper, or brass flat stock on a punch press.

I design some punch dies years ago. Hadn't even considered it for this. Its an option, but a big fancy punch press is probably out of my budget. I'll have to calculate the shear and see if it can be done with one of my shop presses or perhaps an improvise drop weight press.

I don't think we have any local manufacturers generating that kind of waste. I think Barco metal Stamping closed up some years ago, and the only did light gage for things like construction light fixtures. Still next time I take a load of something over to Yuma Recycling I guess I can ask.

I was thinking that finding the generator of the scrap would be hard, but finding dealers who might resell would be easier. There used to be a few businesses that sold industrial surplus and offcuts for re-use, but I can't find anything of the kind now. Admittedly I haven't looked in at least a decade. The world has changed a lot in the past few years.

I expected non-local, but it looks like non-existent is the rule.

Sorry for the bum steer,

bob prohaska

Its not at all a bum steer. Might not work for me (it might) but its a good idea.

Shop press will do it. Even a good arbour press. Cycle time is slow doing onezies ---

I design some punch dies years ago. Hadn't even considered it for this. Its an option, but a big fancy punch press is probably out of my budget. I'll have to calculate the shear and see if it can be done with one of my shop presses or perhaps an improvise drop weight press.

Bob La Londe

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I've measured up to 2000 Lbs of compression in my milling vise. That was a test of the bearing load an oak rafter could withstand on a joist hanger without compressing (much). The force on the handle was more than I normally need but still one-handed.

Or find someone with an ironworker you can borrow or rent time on. Need to modify the standard ironworker punch by grinding off the "nib" or you will need to press out the "dimple" I can't remember the name of the machine several local fabricators used - for punching, notching, pressing louvers,etc. With a square punch they could basically "nibble" slots in angle iron or plate or notch corners in sheet or plate. I think it was called a "strippit"?. It could punch 1 1/2 inch holes in 3/16" mild steel or stainless all day. The old ones were mechanical flywheel punches then they switched to hydraulics. The one mechanical one I was familiar with was made about 1969 and was still punching away in the early

The strippit was also used as an embossing press IIRC

Ouch, At those prices it would be cheaper to use real money...

Peter Fairbrother

Peter Fairbrother

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I wonder if the stamping operation would adequately flatten blanks cut with a Greenlee punch, guided to not need the center screw. They cut a larger blank with less force than flat-faced punches. The points could be rounded as much as the press allows to reduce distortion.

One company shop had a bench press that located and clamped the lower die between four horizontal setscrews. The punch fit into a round hole in the ram, the square-sided die had two beveled edges for the setscrews. At first it was difficult for me to align but it was very versatile and could punch the square and D shapes needed in electronics.

The punch had a slight taper above the parallel section which would hold the die centered while I adjusted the setscrews. If I had to convert an arbor press that might be an easy way to fixture a die that could be hardened and then surface ground. The Lindsay book on making punches and dies suggests making and hardening the punch first, then using it to finish the die before hardening it.

The old-time answer to this is a Fly Press, which are still used.

Joe

I was going to suggest one also but as I understand it they're not that common in the US, here in the UK they're quite common. I have one and use it from time to time to punch copper blanks for enamelling, I set-up the tooling so I can quickly punch the blanks one after another from a copper strip. For the coin stamping I was thinking of a drop stamp. An image here

They are not uncommon here, and I see them turning up around old industrial areas all the time. They basically do not wear out.

I just checked eBay in the US, had 148 hits, some for presses, some for press tooling. Used machinery peddlers also list them, likely with better prices than eBay.

Those were the days. If there were drop hammers, there would be drop presses as well.

Joe Gwinn