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<p>[QUOTE=&quot;Tom Maringer, post: 176966, member: 7033&quot;]<b>Making coin dies</b></p><p><br /></p><p>They key to making dies is a basic understanding of steel. Steel is an alloy of carbon with iron. At high temperature (like... red hot) the carbon dissolves into the iron and forms various different iron-carbides. But carbon is not stable in iron at normal temperatures! If the hot steel is quenched (cooled rapidly) the carbides are locked in place because the carbon has no time to come out of solution, and the steel is hard. But if it is cooled slowly, the carbon comes out of solution and forms granules in the iron matrix. That is referred to as &quot;annealed&quot; steel and it is very soft, nearly as soft as copper. It is extremely important to understand that the &quot;condition&quot; of any steel piece... whether and how it was heat-treated... is just as important as the alloy of the steel itself. </p><p><br /></p><p>The carbon content of the steel will determine the hardenability of the steel. Mild steel with carbon less than about 0.2% cannot be hardened. Various intermediate steels of 0.4% to 0.6% are sometimes used with mixed results. Good die steel will have carbon in the range of 0.9% up to a maximum of 1.5%. If you go higher than that you get into the range of cast irons which are very brittle. Adding other elements to the alloy generally slows the solubility of carbon and adds other properties. There are thousands of steel alloys known, and more being developed every day. Steel chemistry is EXTREMELY complex... but the basics are fairly simple... and that&#039;s enough to go on with. </p><p><br /></p><p>So for making dies you will purchase annealed tool steel stock. The cheapest is W-1 which is a water-hardening steel (that is, you quench from the austenitizing temperature of about 1550 degrees F into water to harden it).&nbsp; I generally use 2&quot; diameter steel die-blanks 1.5&quot; tall. After smoothing and preparing the top surface of the die, you can lay out your design and begin engraving. Gravers are like tiny wood-carving chisels specifically made for cutting soft steel and other metals. The tools and techniques of engraving are well elucidated in a number of books and videos. Any major jewelery supply firm, such as Rio Grande has a full line of tools. </p><p><br /></p><p>It is also possible to PUNCH into the soft steel instead of cutting it away by engraving. Punches are often used for lettering or small features such as stars. Larger punches called &quot;puncheons&quot; or &quot;hubs&quot; are used for entire thematic elements, such as faces or animals. And of course... you always have to remember to work backwards, since the coin is always a reverse mirror image of the die. </p><p><br /></p><p>After the die-sinking has been down, by whatever means (or combination of means) you have chosen, you then harden the die by heating it up and quenching it. There are heat-treating tables for every different steel alloy and they should be followed closely. After hardening... the die will (or should!) easily withstand the forces involved with striking designs in SOFT metals, such as copper, silver, gold etc. If you&#039;re careful, you can gently polish the flat die surface without impacting the design too much and achieve a near-proof effect. </p><p><br /></p><p>And here I should mention that the process of coining is NOT restricted to the making of coins per se! Metallurgically speaking, coining is any cold-forming process in which the metal FLOWS into recesses of the die under force. It is NOT the same as &quot;stamping&quot; in which the metal is bent and/or sheared, and which requires much smaller forces per unit area. Many items of modern manufacture besides coins and medals are coined... such as watch dials, key blanks, buttons, knobs, pocket-knife handles, gun parts, and face plates. So what that means is that there is a wealth of equipment out there that is perfectly suitable to coining that may not actually have ever been used in a mint. Screw presses and knuckle presses abound on the surplus equipment market. If you want to purchase one you&#039;ll have to start looking at what&#039;s around, and not get too excited and in a hurry. There are quite a few floating around so you can pick and choose. They are heavy, so having a good place to put it, and the ability to load and unload and move the things around is important.&nbsp; A solid grounding in basic metal-shop practice is essential... including lathe-work, milling, grinding, drilling, polishing, sawing, and filing, as well as the more specific tools and techniques associated with die-making. </p><p><br /></p><p>Good luck![/QUOTE]</p><p><br /></p>

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