For the first time, man’s mind and money were set free, and there were no fortunes-by-conquest, but only fortunes-by-work, and instead of swordsmen and slaves, there appeared the real maker of wealth, the greatest worker, the highest type of human being–the self-made man." "
Since 2008, our team has been designing, marketing & distributing cool coins that tell great stories.
In 2012, we even tried our hand at manufacturing our own coins. It didn’t go well at first. It took our team a long time to figure out the winning combination of machinery, manpower, capital & competency necessary to reliably mint a quality coin. Today – a full decade later – we’d like to think we have it all figured out. And in fact we pretty much do! Our production facility is able to coin more than 10,000 1oz rounds per day…that is, when everything is working correctly.
But still, we’re learning more each and every day, and discovering new & better ways to operate safely & efficiently. We owe much of our success to a few industry friends that helped guide us along the way, sharing valuable insight and expertise that has helped us tremendously over the years.
Thinking about starting your own mint?! Don’t do it! It’s a lot of work. The machines are heavy, expensive & hard to find, and downright dangerous to operate at times. There’s very little profit in minting silver bullion, and market demand is extremely unpredictable.
So if starting a mint is such a bad idea, then why did we do it, you ask?
Long before we had a mint, we started with a great story. We tell that story in silver. It just so happens that finding reliable vendors to service our manufacturing needs is all but impossible. After a lot of research, we decided to mint our own coins. We didn’t arrive at this conclusion overnight, and from time to time we even wonder if we made the right call.
Today, we’re quite proud of our production facility. Even so, we still don’t really think of ourselves as a mint. We think of ourselves as storytellers & artists. Our canvas is a 1.5 inch round metal disk, and we take great pride in our ability to effectively communicate epic tales in such a small space.
If you’re still dead-set on setting up your own shop, check out the machines and processes below to get an idea of how it all works, from start to finish.
Makin’ it Grain!
The cheapest silver material we can get our hands on is the 1000 ounce “Good Delivery Bar”. This is the behemoth the banks trade by the pallet. It weighs somewhere in the neighborhood of 70 pounds, hurts like heck when you drop it on your foot, and is just about completely unusable for making coins.
If large bars are all you can find at an affordable price, you’ll first have to turn it into “casting grain”. To do this, we use an induction furnace designed with a giant graphite crucible that’s just big enough to contain a thousand ounce bar. It takes about 37 minutes for the bar to heat up, liquify & drip out through holes in the bottom of the crucible.
The molten silver quickly discharges into a giant tub of pure water. It takes about 5 minutes for the bar to melt and drain, and it’s a lot of fun to watch!
A few things we learned about this process:
- keep the discharge tank water super CLEAN – dirty casting grain does NOT cast nicely
- keep the discharge tank water super COLD – as the water heats up, the material clumps together
- we can melt about 40-50 large bars before the graphite crucible wears out
Once you’ve got 999+ fine silver in a more usable form, it’s time to turn it into a long bar. There are lots of ways to do this, the two most common are continuous casting & extrusion. Extrusion is a lot of fun – think of a play doh spaghetti maker. If you’re not quite ready to extrude a few hundred thousand ounces a day, continuous casting will work just fine for you.
Here, another induction furnace holds a graphite crucible. This time, the crucible is attached to a die that shapes the molten metal into a specific size. For us, we cast an 82 x 10 millimeter bar. In about 6 minutes, we’re able to cast a 30″ bar that yields just over 100 coins.
It’s important to keep an inert atmosphere above the silver when it’s hot and reactive in its molten state. So, we pump Nitrogen gas into the melt chamber to discharge oxygen. This helps keep the material from oxidizing, and slows the rate at which the coins turn yellow or brown.
The caster gulps down energy, and so we spent a small fortune installing 3-phase power to our property. Fortunately, we have 800 amps of service at 480 volts, allowing for lots of capacity and future expansion. With a single caster we’re able to cast enough bars to make in excess of 5000 coins per day, and so we run TWO casters on busy days!
You See Me Rollin’
The downside of casting is that the new silver bar has lots of concentric work lines in it, which must be smoothed out before we can punch the coins. That, and it’s about 4x thicker than what we need for a 1oz coin. So, we pass the bar 18 times through a heavy duty rolling mill!
Rolling is an art. The Rolling Master’s technique has a direct impact on the weight of the final coin – if it is too heavy or light – & the ease at which the new strip is fed through the punch press. Unfortunately, the rolling process is not a “set & forget” station. If the rollers heat up, or if the strips cool too quickly, or the operator uses the micrometer differently – each of these can have an impact on the thickness of the strip and how consistent that width is throughout the entire strip.
One thing that’s amazing about the rolling process is that the silver bar ONLY gets longer! In fact, a 30″ bar turns into a 10′ strip, while the width stays exactly the same. It takes our crew about an hour to turn 16 cast silver bars into strips with a thickness of 2.48 mm, about 1/4 the starting thickness.
Apparently, crush videos are pretty popular on the ‘nets these days, so be mindful of operators getting creative with the rolling mills when you’re not looking. Safety first!!
The Cookie Cutter
Finally, it’s time to make a coin! Our punch press is a 45 ton “OBI” knuckle-joint press, and finding these on the machine market is pretty easy.
We designed a custom tool that fits our 82mm wide strip, and punches two coins out at a time. The hardened steel punch tool cuts through the silver strip like butter, and each stroke of the press causes 2 “parts” to drop into a bucket below.
Be SURE to keep your hand clear of the punch press tool! Trust us…we speak from experience!
Since the punch tool cuts parts to a specific size – we use a 1.523″ diameter die – it is the thickness of the strip that determines just how close we get to a perfect 31.1 gram 1 Troy ounce silver coin. If the strip is too thick, the coin will be overnight and you’re giving away silver. Too thin and you’ve got a reject.
Scrap from the punched out silver strip – about 30% of the original weight – goes right back into the caster and is melted to start the process all over again.
The Rim Job
At the next station, each coin is individually weighed to make sure it meets our weight tolerance – we reject any coin that’s below 31.10 grams or above 31.50 grams. A perfect coin of course is an exact 31.10 grams, but this number is difficult to obtain when rolling by hand. So, we set a maximum allowable weight threshold, and calculate this value into our raw material acquisition. With an average weight of 31.3 grams, we need to purchase an additional 6.5oz of silver for every thousand ounces produced. What a mess!
Once the coin is weighed and accepted, it quickly passes through an upsetting mill – or “rimmer” as it’s known in the industry, which reduces the overall diameter of the part from 1.523″ to 1.518″, while distributing that affected material to the edges of the coin. This seemingly insignificant process is actually quite important, and good luck getting your hands on a rimmer! We had our custom built from an engineer in India.
Rimming the coin performs two functions: first, that extra material near the coin edge helps give it that nice thick outer rim. Second, and possibly more importantly, the rimming process keeps the parts from cold welding and sticking together as they go through the rest of the manufacturing processes, leaving them machine-feedable and easier to handle.
Soften Up a Little
All this work done to silver part makes it super hard, and a hard blank requires a lot of pressure to mint into a nice coin. Further, any time silver material is worked beyond a certain point, the grain structure of the material is affected and needs to be realigned. There’s some metallurgical stuff going on here that a scientist can explain better than we can, but the point is this: the silver blank needs to be softened before it can continue through the manufacturing process.
So, in a batch furnace with a little more Nitrogen, we heat the coin back up to a whopping 875 degrees celsius for 10 minutes. When properly annealed, the part will feel kinda tacky.
Time for some Shiny
One last step before we’re ready to mint! All these manufacturing processes can leave our little silver part feeling a bit roughed up & dull. To brighten its day, we toss it in a high-energy burnishing barrel with a polishing compound & stainless steel “satellite” media for 10 minutes, and wow, what a difference it makes!
The burnished silver part comes out smooth & shiny! We put the blanks through a series of rinses, involving deionized water, malic acid, denatured alcohol, and more DI water to achieve a spotless mirror finish.
The finished blanks are sealed in a bucket with moisture absorbing packets to keep them clean & fresh until we’re ready to strike.
360 Tons of Fun
90% of what goes into minting a nice coin is just making the shiny silver blank. That’s the hard part, and if you want to make coins and can find a reliable supplier of silver blanks, you’re off to a much better start.
There are lots of different coin presses out there. We use hand-fed HME 360’s, mostly because we got lucky, found quite a few of them, and decided to standardize with this model. Most small shops will use hydraulic presses, and they work just fine as well. They’re not quite as fast, but will do the job. We really like the way the knuckle-joint HME’s smash the blank so hard & so fast, resulting in a style that we’ve come to know & love.
Even so, there’s a lot that goes into coining. You’ll need a press, a coin tool, a set of dies, and a coin collar. Once again, there’s no one-size-fits-all setup here. We have different size dies, collars and spacer plates that are interchanged depending on the job and required tonnage. Usually, we hit a blank with ~100 tonnes of pressure to get the design to pop up the way we like, but each coin is a little different, and can even differ based on if the blank is thicker or harder than usual.
Running the presses by hand (for now), we’re able to mint about 800 coins per hour with a dedicated operator. A single press can exceed our 5000 ounce per day target, and two presses easily reach our 10k daily production goal on busy days. Unfortunately, the efficiency is reduced when we have lots of different designs to mint; a die set change can take 30 minutes to tear down, set up and dial in! The best case scenario for us is that each job is for 5000 coins of a single design – a days work on one press.
- only load a single blank in the press at a time, otherwise you’ll blow out the collar ($750+ mistake)
- when using a hydraulic press, be sure to put in a blank! Otherwise you’ll coin the dies together ($1000+ mistake!)
- dies “mushroom” over time or when you hit them too hard, and mushroomed dies get stuck in (or break) coin collars
- knuckle-joint presses need LOTS of clean, dry compressed air! We use a 30 horsepower screw-type compressor – it’s a beast!
Quality Control & BEVIS
Once the coins are struck, each is once again hand-analyzed for weight and quality. We don’t reject imperfect coins, as we’re making primarily bullion coins. But we do look out for spots, bad scratches, dents or other evidence that a coin isn’t up to our standards. We pack them up in tubes of 20, weigh the tubes to make sure we got them all, then seal the tube closed with a BEVIS sticker.
BEVIS – the Blockchain Enabled Verification & Information Service – is a tool we developed to share with our customers valuable manufacturing data. It also helps us keep excellent track of every tube that leaves the building. Quite often we are asked “how many of this coin did you make?”. With BEVIS, we can quickly and accurately answer that question with confidence.
Tubes are packed 25 to a carton, sealed with a label, and stored for palletized shipment to our distribution partners.