Diamond shears

What it is

Diamond shears have angled blades with the sharp edge on the inside, and are used for round cuts.⁠^⁠[1] Their blades form a diamond shape when partly open,⁠^⁠[3] which is where the English name comes from: the opening in the middle looks like a cut diamond.⁠^⁠[2] Most also have a small round indentation at the end of the blades.⁠^⁠[2]

How it’s used

Turning the piece while closing them, a glassblower can press a round valley into the glass, cut the end of a piece off in a round shape, or cut a gather an assistant brings to the bench into a neat round form.⁠^⁠[2] Squeezed hard, they can free a sculptural piece from the punty where the colder glass breaks.⁠^⁠[2] Wikipedia’s summary is simply that they’re “used for cutting off masses of glass”.⁠^⁠[3]

The indentation at the tip holds a pipe or punty: when an assistant brings a bubble or a gather down onto a piece, the master can hold the rod in it to guide it into place.⁠^⁠[2]

History

Murano’s glass museum lists tagianti tonde, diamond shears, as one of the glassmaker’s two kinds of shears, next to straight shears.⁠^⁠[1] Tonde means “round”⁠^⁠[2] , the same as the Czech name, kulaté nůžky, used by the Nový Bor shear maker Mitiska.⁠^⁠[4]

Writing from the United States, the author of the Conciatore lexicon notes that some American diamond shears are made with a fully round opening instead of a diamond, some without the indentation at the tip, and that some flameworkers prefer the round hole.⁠^⁠[2]