tower

A tower is a vertical metal stand, typically made of cast iron or steel, that serves as a fixed pivot point during glassblowing and glass finishing operations. It is positioned at the working edge of a furnace and holds a punty rod (the iron rod used to carry a glass piece) at a consistent height and angle while the glassmaker works on the object. The tower keeps the punty steady and allows the glassmaker to rotate or manipulate the piece without having to support its full weight by hand.

The tower consists of a heavy base, usually weighted or bolted to the floor, and a vertical post with a socket, hook, or rest point near the top. The punty rod sits in or against this rest point. The design must withstand the radiant heat from the furnace and the repeated mechanical stress of the glass piece settling and shifting during work. Cast iron towers are common in traditional glasshouses because they retain heat moderately and are inexpensive to replace when they crack or warp.

Towers vary in height, weight, and the type of rest they offer. A simple socket tower uses a hole drilled through the top; the punty rod passes through and rests on a ledge or bushing inside. A notched tower has a V-shaped or U-shaped groove cut into the top rail, allowing the punty to sit in the groove while still being rotatable. Some towers include adjustable arms or tongs to grip the punty. The position of the tower relative to the furnace mouth is critical: it must be close enough to keep the glass within the working temperature zone but far enough away to protect the metal from direct flame.

Wear and thermal cycling cause towers to develop cracks, particularly in cast iron where cooling stresses concentrate. A cracked tower that allows the punty rod to shift unexpectedly will spoil a piece and is a hazard if the glass falls. Regular inspection for cracks and loose bases is standard maintenance. Towers are sometimes replaced with adjustable iron stands or motorized carriages in modern production settings, but fixed towers remain the norm in studio and small furnace work because they are reliable, passive, and require no power.

The term "tower" likely derives from its prominent vertical profile and its role as a fixed marker at the furnace workstation. It appears in glassmaking vocabulary from at least the 19th century and is distinct from the punty rod itself and from the punty iron (the end of the rod that touches the glass). In some European furnace rooms, the tower is called a "punty rest" or by language-specific equivalents, but "tower" remains standard in English-speaking glasshouses.