GLAZIERS’ DIAMOND
The luxury yacht of 100 years ago could be a veritable crystal palace of broad-windowed deck saloons and prettily glazed furniture. Like their bejewelled owners and guests, the accommodation was aglitter with reflections from lead-lighted display cabinets executed in rare woods. But what would the 1920s yacht glazier make of modern glazing, I wonder?
Today’s designers choose from a menu of marine glass that’s transformed the yacht with possibilities both practical and aesthetic. Addressing safety, the Jekyll-and-Hyde character of old glass turning from light and protective friend into cut-throat enemy when smashed, was cured of its duality by toughening. But chemically or thermally toughened glass that breaks into small and relatively harmless pieces could be less handy in the event of a capsize on account of the gaping hole it leaves behind. Hence laminated glass in which two layers are bonded to a clear resin is often specified for its ability to hold the broken pieces together. Yet both types would defy cutting with the traditional glaziers’ diamond, as would the heated glass used to resist fogging on the bridge, the ‘smart’ privacy glass that switches from clear to opaque, and bullet-proof glass demanded by the security conscious.
The diamond is set in a brass bezel on a head which may swivel to accommodate curved work. Radcliffe’s optimistically named ‘Infallible’ model, shown above left, has an all-brass head and also a ‘rack’ of notches used for snapping remnants of the break that are too small to be gripped by pliers. Notice also the ‘jockey’ wheel, which helps steady the tool. The cutter next to it, made by A. Shaw & Son, has a steel head that’s sloped to suggest the working angle, although the optimum for a given diamond is invariably found by trial and error. The convex back of the Shaw tool is for tapping below the scored line, further weakening the glass before breaking by pushing down on that part overhanging a straight edge.
Prices varied according to size and quality of the diamond, the most expensive being for plate glass of
1/4in thickness and above, and in time the diamond gave way to the cheap and replaceable steel wheel. The brass 1920s cutter shown above stored spare wheels inside the handle – today they are usually mounted in a revolving turret.
NEXT MONTH: Upholsterers’ Hammer