I would like to attempt making some silver "family" coins for gifts this christmas. I have some rough attempts at a die for the coin, but before I get too deep into the project, the question came up as to the raw material. I need to get some silver coin blanks (planchets). I know they exist somewhere, a friend got a medalion stamped at a Ren-fair and they offered brass, silver or gold that they stamped with your choice of two different dies. I have done numerous searches but have not come up with a supplier for 'blank' coin size silver. Anyone got a suggestion other than casting or punching my own?
You don't say where you are, but if in the US, try Indian Jeweler's Supply, RioGrande, or Metalliferous. They'll all sell silver rounds. The problem you may have is getting them thick enough for coin blanks.
I know you were looking for alternatives to making your own, but the cheapest and simplest way to do this is to sand cast them. A good source for cheap silver casting metal is to buy broken silver tableware at the local flea mart -- most of them have someone selling singles to fill in sets missing a piece or two. Ask that guy for his beat-up pieces, and tell him you'll pay in-between the recycler's price and spot. I usually can buy a few pieces every time I visit.
BTW, what are you going to use to strike the coins? You need a pretty big press or heavy drop hammer to do it right. Those guys at the Ren fairs use a drop hammer that falls about 5-6 feet, and the weight is substantial -- the die holders smoke where they sit on the wood base after each strike, which gives you an idea how much energy is involved. I've tried coining with a big hammer on an anvil, and it doesn't work very well except for very small rounds.
I live in NJ. I was looking at doing a small coin, my tool steel stock sort of limits me to a "penny" sized coin, or a "penny" sized imprint on a larger coin. I was only going to imprint one side with the family coat of arms. The drop hammer is a foot and a half chunk of railroad rail that will drop down a PVC pipe. I already have some coin silver spatter that my dad got years ago when they called in the silver certificates and I could cast or work that, but with all the other work involved, I was trying to go the easy route on the raw material.
Thanks for the suggestions of Indian Jeweler's supply, RioGrande and Metalliferous. I hope they have web sites. ;-)
I'm surprised that you use metal this thin. I'm overseas, haven't got my mike with me to measure some sample coins, but I would think a much heavier blank than that would be needed for anything over tiny sizes
-- I was thinking 2-3 mm at the least,for a nice medallion-sized piece. The 1-euro coin I just pulled out of my pocket looks to be at least 2 mm thick, possibly more, by the old eyeball mike. .035" is well under 1 mm; don't they come out pretty thin?
No, it doesn't; but I wasn't recommending he cast the coins -- just the blanks! Although, with fine casting sand (like Delft Clay, for example) you can cast some pretty fine detail. I practiced on coins when I was learning to use it. They come out pretty good -- but I agree, not nearly as sharp as a good die-struck piece.
You guys must have arms like gorillas, is all I can say..:-) Maybe it works on real thin stuff, especially fine silver, which is pretty soft
-- but I cold-forge thick ingots regularly prior to rolling into sheet, and anything over a couple of mm thick needs some serious beating -- no way would I get a good die impression on a thick coin with one strike.
Maybe with two guys, one holding the dies on the anvil, the other with a two-handed sledge....?
IT is not the size of the coin the determines the required thickness of the blank, but the depth of the die impressions.
Just slightly thinner than they go in. Even on a punched die the impressions are not all that deep, and the silver does not flow to full depth either. In an engraved die the depth is even smaller.
Not most of us, no
When annealed, yes.
Fully annealed, yes you can, with a good die.
We usually use a 3 man team. One to hold the dies, one to place the planchets, and one to strike. In pewter, we can reach rates of ~1.5 coins / sec, with averages of ~240/hr including breaks, and discounting bad strikes.
Our usual striker used a 2 lb sledge with a 24" handle, two handed.
I use that one one handed, but prefer my short handled 6 lb or 8 lb sledges with a short (~16") handles, swung single handed.
we performed coining on half hard brass blanks, 1.5" diameter used a press rated for 60 tons it was necessary to anneal the blanks beforehand, a softer aloy would have been better, but these were suplus we had on hand
the first attempt taught us a lot
the second project produced beautiful coins with great detail and clarity