Brass V-Necking tool, Great for reducing the diameter of a section of tube, or for scoring and snapping a section.
Brass Necking Tool for constricting hot glass. Just roll hot glass in the V shaped tool to constrict and cool glass. Tool makes even constriction for texture or even a clean break. For breaking just wiggle the glass after it is constricted until the glass cools and stiffens then it will separate with ease.