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Tips from Ian

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  • GTSport@aol.com
    Hi All, There hasn t been too much activity on the vboard lately so I thought I would post some excerpts from the E-mails I recieved from Ian Cnulle earlier
    Message 1 of 1 , Nov 3, 2002
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      Hi All,

      There hasn't been too much activity on the vboard lately so I thought I would post some excerpts from the E-mails I recieved from Ian Cnulle earlier this fall.  These should be of interest to those of us who are just starting out and don't have access to someone of Ian's skill level locally.  My questions will be preceded by a >.  Also, I have added a few notes of my own for clarification when I think it is helpfull.  Part of the first paragraph will be of more interest to those of you in the Northwest.

      What I do is hand engraving with the traditional 'burins'.  I'm self-taught, learning the basics of how to setand use the tools from jewelers (the gravers and handles are available from jewelers' supply catalogues), with a few tips on adapting that to engraving tool steel received from a professional engraver in England, who I met at an ANA convention back in 1990. I teach the basics to Apprentices of the Moneyers' Guild in the Society for Creative Anachronism.  Unfortunately (for the possibility of my teaching you), I live in Silverton, Oregon, and am very much disinclined to travel any further than a couple of hundred miles from my home (and then only reluctantly).  So, unless you want to visit western Oregon, about the only help I can offer would be consulting via e-mail (which I do a lot of).
      Actually, once you have a grasp of the basics, hand engraving is very simple (if slow and tedious).  The main thing to learn is just getting the
      feel of how the tool interacts with the material, and the only way to learn that is just to do it.


      >Some of the early English coins I've seen look like all the lettering was made with just a couple of punches -- straight, right and left curve, and
      half circle -- struck at different angles. 

      It's a little more complex than that, but you've got the basic idea.  The simplest lettering I've done (again, on the silver trade penny) required
      building up the letters with half a dozen to a dozen simple geometrical shape punches (e.g. there are several sizes and shapes of triangles).
      Actually, my mid 13th century model coin (English long cross penny of Henry III [although I based my current short cross reverse on a 12th century
      French Feudal denier]) was minted in a transitional period when they were starting to use whole letter punches, e.g. a single punch for the S instead
      of two impressions of a semi-circle and two impressions of a triangle for the serifs.  I also made a single punch for V (= Latin U, inverted for
      making A), while on earlier dies I used two separate triangle punches.

      On my "fleur d'argent" silver trade coin, I used two sizes of a set of more elaborate late 13th to early 16th century style letters punches, which has
      many more whole letter punches, but many letters are still built up with two or three punches.  For my gold florin, I made a partial set of smaller
      size punches of similar style.  (The inscriptions on both types of gold tremissi are all engraved rather than punched.)  I've also made a set of
      Roman Capitol style letter punches based on Elizabethan models (i.e. a slightly archaic version of modern coin letters) that is almost all whole
      letter punches (although I use, for example, the same 'tail stroke' punch to turn a P into an R and an O into a Q).  [Also, you might want to look at
      the "Middle Earth" 'hobbit' coins that I've made dies for, illustrated at www.Shirepost.com; I made a couple of sizes of letter punch sets for
      'Feanorian tengwar' (elven writing) - just about everything can be written with half a dozen punches.]

      >What size and shape steel do you use for your dies? 

      4" lengths of 1" diameter W-1 drill rod.  NOTE:  I use  O-1 drill rod which should work as well.  This is also the material I use for making punches.  Two 36 inch by 3/16 inch rods which will make around 18 punches cost less than $4.00

      >What method do you use to harden the steel? 

      For most of the SCA coins, medals and tokens (e.g. my silver and gold trade coins, the An Tir/West War commems, &c.) the dies aren't hardened because
      we're only striking small quantities (typically a few hundred pieces) on soft metals (e.g. pewter, fine silver, and fine gold).  I have had a few
      dies heat treated by an associate who uses a propane refractory; he doesn't do anything to prevent firescale.  It's better to have it done by
      professional heat treaters (but you have to make sure that the guys accustomed to heat treating machine parts don't use sandblasting to remove
      firescale from your dies) - if necessary, but they usually charge a minimum of $35 - an unnecessary expense for most of what SCA moneyers do.

      >Do you cut directly into the die or do you cut a positive and strike it into  the die? 

      I cut directly into the working die.  I'd like to try making and using "puncheons", the forerunner of hubs (dating from the 14th century), but I
      haven't yet had occasion to. 

      >Do you have some kind of jig or fixture to hold your punches (if used) straight as you strike them into the die? 

      No, but I should for doing the later style inscriptions with the Roman Capitol style punches.  The problem isn't holding the punch straight, but
      rather positioning and orienting the letters precisely.  (On medieval style coins, the letters were usually between double border circles, making
      positioning easier, but also medieval coin lettering was typically sloppy - it doesn't look bad on a medieval coin, but it looks awful on a modern
      style piece with broad empty fields.)  Ron Landis had an article on making a punch holding jig on the Gallery Mint Museum site.

      >What do you use to hold the dies when you strike coins? 

      The 'pile' (i.e. 'anvil die') sits in a hole in the 'anvil' or 'bolster' (actually a cylindrical chunk of mild steel), while the 'trussel' (i.e.
      'hammer die') is hand held.  For anything bigger than a penny, that requires two-man striking - one holding the trussel, the other wielding a
      6# hammer with a 2' - 3' handle.  When I'm striking larger coins at home alone, without anybody to hold the trussel for me, I use a wooden jig to
      hold the trussel in position above the pile.

      >Do you hot strike or cold strike? 

      All of the western European medieval style stuff is cold struck.  However, members of the Moneyers' Guild of An Tir have hot struck a Byzantine style
      copper 'follis' (1" diameter and 1/8" thick).  That takes a four man team; the 'fornacator' manages the furnace/forge/refractory and sets the hot
      blank on the pile, the 'supositor' positions and holds the trussel on top of the hot blank (and incidently, controls the whole operation of the
      team), the 'malleator' strikes with the 6# hammer, and the 'lavator' takes the freshly struck coin (encrusted with firescale) with tongs and drops it
      into the pickle bucket (i.e. acid bath).  

      >If hot, how do you heat them, when do you know if they are hot enough, and does the hot blank have any effect on the hardness of the dies? 

      For the above described folles, our forge was made out of some refractory brick and old chunx of concrete with a couple of expanded steel mesh
      grates.  We were burning anthracite coal, and using a ShopVac with a 3" hose on its exhaust for the draft (got it hot enough to melt one of the
      grates and some of the blanx).  I also make dies for the "University of St. Hildegard" for striking $1 copper trade coins of the same size as the above
      described folles (I think they're illustrated at Saydo.org/PastLaneProductions, but I'm not sure if that site is
      problem-free operational at the moment).  All of those dies are heat treated as described above, and they've stood up to many thousands of
      strikes without any noticeable wear on the die faces.  (Other than that, I have no idea what sort of metallurgical effects may be occurring.)  The
      blanx are heated in the propane refractory until they're glowing bright orange.  It just takes practice (I have specimens struck on blanx too hot
      [melty edges] and too cold [light impressions]).  

      >Do you shape the planchets in any particular way before striking? 

      For the cold struck medieval style pieces, the blanx are cut out of sheet metal (typically .5mm thick for fine silver, .7mm thick for pewter) using
      long handled 'blanking shears' with one handle fixed (what machine shop guys call 'beverly shears' - however, our tool is based on medieval
      illustrations).  For projects requiring much more than a hundred blanx (unless we've got Apprentices to keep busy), the quick and dirty way is to
      cut the blanx out of the sheet using a ring punch (or 'annular punch' or 'stirrup punch', &c. - there are a variety of tools, as well as names for
      them).  Edges of the blanx can be smoothed on a file, if that level of finish is desired, or a stack of coins can be beaten on the side to smooth
      the edges after the coins have been struck (which apparently was done on some original medieval types), but we rarely go to that much trouble.

      For the hot struck coppers, the blanx are punched out of 1/8" sheet copper with a 35 ton hydraulic press, and the resulting burr is ground off on a
      belt sander.

      >How do you lay out your design before cutting the die? 

      I scribe border circles with a plastic template and mark the right angle points (also indicated on the template) for scribing vertical and
      horizontal center lines for reference in sketching out the design with the scribe.  Many medieval style coin designs are very simple and symmetrical,
      but the most elaborate designs I've done have required laying out a reference grid (e.g. that's how I developed the sketch for the portrait on
      the Darius denarius from a photograph of the subject - although I didn't actually succeed in producing a very accurate portrait!).


      >How fine do your burins (gravers) go down to?

      My round burins (used for sculpting small rounded shapes) are numbered 52, 53, 54, and 56 (that's how they're listed in the Gesswein catalogue) with
      the diameter of the end ranging from about .5mm to almost 2mm.  With the square and oval burins, the size of the overall tool doesn't affect the
      size of the point - with a bigger burin, there's just more metal to grind away to sharpen them.

      >Even though I have a fair idea about the process involved, it still is amazing. 

      I've got a professional secret to share - all of the tiny detail that loox so impressive is really easy to do (all it takes is adequate magnification
      to see what you're doing); the hard part is large simple shapes with no texture or detail (e.g. cheek and forehead of portraits) - it takes me
      forever to get them smooth. 

      >Speaking of metal, what kind of store should I go to for pewter or copper plate? 

      Any hardware store with plumbing supplies should have leadless solder (usually 95/5 tin/antimony, although there are various alloys - just don't
      get one with lead).  As for copper, I rarely use it because they generally didn't use copper coins in western Europe throughout most of the middle
      ages (e.g. the English Royal Mints didn't mint a copper coin until 1672). The Eastern Roman Empire minted coppers extensively, and the St. Hildegard
      coppers are inspired by 'Romaion' folles.  For striking those, Watt buys sheet copper at Alaska Copper & Brass, a big industrial specialty supplier
      in Portland.  I've struck a few merchant tokens on thinner sheet copper that a jeweler friend (who lives in Portland) gets at the same place.  So,
      your bottom line is that's the kind of place you'll have to find locally if you want to mint copper.  

      >Also, I noticed I have some copper pipe in my garage.  If I were to put it through the rolling mill, do you think it would be soft enough to strike
      or  would I have to anneal it?  NOTE:  Playing with the copper pipe recently, I have found that heating it until it glows and then plunging it intowatermakes it soft enough tobent with your hands.

      I have some local shire beer tokens (minted ten years ago or more) that were struck on flattened out pieces of copper plumbing pipe (cut open with
      shears), so, yes, it worx.  I wasn't involved in their production, so I don't know if they annealed the copper before striking (I do know that most
      of their tokens were overstruck on old bronze Lincoln cents, and to do that they annealed the coins on a stove top burner).  I'm pretty sure that they
      didn't run the pipe copper through a rolling mill before striking - evidently that wasn't necessary, although those tokens were quite crude.
      My concern would be that running the pipe copper through a mill would work harden it, requiring you to anneal it, which otherwise probably wouldn't be
      necessary.  You'll just have to experiment - but that's part of the fun.


      This is all I have time to transcribe right now.  I will post more later.

      Ciao Tutti Voi

      Joe
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