Since the dawn of glass lamp shades, glassmiths would create decorative ornate pieces. Perhaps they were commissioned for a specific design or maybe they were making shades for a production of lighting. Either way, one questions remained: fitment. How was this designed shade going to fit on a lamp fixture?
Fortunately some standardized sizes were adopted by the lighting industry and they are still in use today. Traditionally shades were mounted to a fixture with a lipped edge (Figure 2). The shade holder would use a series of set screws (normally 3) to mount the shade to the fixture.
For smaller shades, also known as fixture shades, the fitter size is known as a 2 1/4 Inch Fitter. These shades are common in sconces, pendants, pan lights, bathroom fixtures, floor lamps, and many more applications.2 1/4 inch shade holder, fixture shade, and set screws. Loosen screws so the shade lip can seat in the base of the shade holder, then tighten the screws evenly to firmly hold the shade in place. Pliers or screw drivers are not recommended since they may apply too much pressure on the shade.