Metalsmith Shop Talk: More on Rolling Mills
Confession, I’m not well versed in the awesomeness that is a rolling mill. There, I said it. It’s one of those tools I’ve never taken the leap to invest in, despite knowing that many jewelers consider it essential to their metalsmithing studios.
I finally decided I really needed to dig into this tool and find out more. My rudimentary knowledge is that they squish metal. Obviously, I have a thing or two to learn. There’s no better place I know to turn to for research than a book! In this case, Helen Driggs’ The Jewelry Maker’s Field Guide: Tools and Essential Techniques has a wealth of information on what she calls “one of the ‘Holy Grail’ tools of the workshop,” rolling mills.
ROLLING MILLS are an important tool for every workshop. They can be used to reduce the thickness of ingots and sheet and to reduce the dimension of wire. Rolling mills also allow one to transfer texture to other metals. The rolls of a mill must be parallel, and each pass of the metal through the gap between them will reduce the total thickness or gauge of the sheet, while at the same time the length and width of the sheet spread are increased. Pattern rollers are available for some older mills, which produce consistent rolled textures similar to Florentine finishes, some floral patterns, and other designs.
Helen goes on to share the step-by-step process for embossing with a rolling mill. If you’re a new rolling mill owner, or want to go from spreading metal to texturing it, you’ll want to pay close attention to these steps.
EMBOSSING WITH A ROLLING MILL
(Excerpt from The Jewelry Maker’s Field Guide)
Although a rolling mill is a large investment, it can be used for many purposes: embossing; reducing the gauge of metal sheet; transforming ingots into wire, rod, or sheet’ and for milling square or round wire in specially grooved rollers. Each mill is different, but all should be treated with care.
1. Metal ready for the mill should be clean, oxide-free, annealed, and bone dry. Wet metal causes the rollers to rust, and oxides on the metal become embedded in the sheet when compressed, so they must be removed completely. Always pass the metal through the center of the rollers. Sandwich the source pattern within the metal to be printed: both the top and bottom sheets will be impressed by a two-sided object during the roll printing. For single-sided roll prints, a copper or brass backing plate should be used to protect the rollers from damage. (FIG. 1)
2. Make a dead pass – one at exactly the gauge of the metal sandwich – with no attempt to reduce the thickness. Make a note of the measurement for the dead pass, using the roller gauge measurement dial. (Fig. 2)
3. The roughing pass is the first live pass through the gap in the mill. To make it, adjust the roller gears to reduce the gap one-quarter turn from the measurement determined during the dead pass. Check the evenness of the metal as it exits the rollers and try not to disrupt the pattern source if another pass is needed. (Fig. 3)
4. Most embossed patterns are made with one or two passes at most. Reduce the gears one-quarter turn for each live pass. For reducing the thickness of unpatterned sheet, the metal type and its thickness will determine the maximum amount of rolling. Usually three or four passes are the maximum reduction before the metal needs to be annealed. Work-hardening will cause rolled metal to split horizontally; but do not anneal before the final pass if the metal is to be sawn. (Fig. 4)
Along with Helen’s valuable how-to information, my rolling mill research was broadened with Richard Sweetman’s must-have video, Metalsmith Essentials: Get the Most Out of Your Rolling Mill DVD. Richard says there is a freedom that comes with working a rolling mill. You’re no longer limited by what you can buy in stores; you can create your own patterns, textures, and designs when milling your own metal. Seeing the textured plate and annealed metal sheet rolling through the mill has me imagining so many new jewelry ideas. It’s easy to understand why so many can’t live without this beast in their studio.
Editorial Director, Books
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