A glass lathe is a tool used by glass-making companies and glassblowing hobbyists. The glass lathe differs dramatically from a traditional wood lathe, and is similar only in that it is designed to rotate an object. Unlike the wood lathe, it contains no cutting tools, and is not used for grinding or cutting. Instead, glass makers use the lathe to expand and shape glass into bottles, scientific glassware, and artistic works.
On a standard glass lathe, each end of the device features a rotating chuck designed to hold glass tubes in place as they rotate. Some type of heat source, such as a blowtorch, is positioned along the center of the lathe. This torch heats the glass as it rotates, making it soft and malleable. By softening the glass in this way, craftsmen are able to blend many different types or colors or glass together into a single object.
The glass lathe also features a carriage, which allows workers to shift one end of the object off center as it rotates. This stretches the hot glass out to form different shapes. Workers also utilize a built-in breathing tube, which enables them to further expand the glass, much like in traditional glassblowing. As the glass rotates, craftsmen may apply a graphite block or paddle to the glass, which further shapes the surface of the object.
One of the primary advantages to using a glass lathe rather than blowing glass by hand is that it allows workers to perform complex work in less time. The lathe holds the object in place, freeing up the hands to shape and form the glass at the same time. In traditional glassblowing, workers must hold the glass as its heated, then quickly apply forming and shaping techniques before it cools and hardens. A glass lathe also exposes the glass to even, consistent heat, which makes it much easier to manipulate harder materials, like quartz.
Of course, the glass lathe may also pose some challenges and limitations for craftsmen who are used to more traditional glassblowing techniques. The size of each object is limited by the spindle length of the lathe, or the distance from one chuck to the other. Workshops may require several different lathe sizes to accommodate objects of different sizes. Some classical glass-making techniques that are common in hand-blown glass may not be possible when glass is turned on the lathe.