Lampshades and Harp Sizes

Lampshades come in all shapes and sizes but the most important factor when shopping for a new shade is to get the right size for your lamp. Without the proper fit, the lamp will not function properly or look attractive. The lamp base is what holds the shade, and the harp is the component that connects it to the base. Getting the harp size right is essential, and this article will teach you how to do it easily.

The harp is a flexible U-shaped piece that fits over a lamp socket and bulb, protecting the bulb from harm and providing the attachment point for lampshades. It is attached to the lamp base with a harp saddle, and small caps on either side of the harp saddle complete the rigid loop onto which shades and finials are lowered. Harps are typically made of metal wire. They are available in a wide variety of colors, finishes and styles to compliment the look of the lamp or the surrounding décor.

Standard assembly lamps, commonly called spiders or standard lamp shade, feature spokes that radiate out from a central hub to hold the light bulb and the lamp harp. The top of the spider has a small ring that slips over a female threaded rod, usually 1/4-27F (these are sometimes labeled as washer fitters). The finial is then screwed on the ring to secure the shade to the harp.

Most harps are two-part, which enables the height portion of the harp to be changed. This enables you to correct problems like the lamp shade sitting too high or low on the lamp.

If a new lamp shade does not have the same height as your old one, it may be possible to change the height of the harp using an adjustment ring. These rings can be purchased from most hardware stores and are usually sold with a matching finial to attach to the ring. The harp adjuster rings are sized to match the harps they fit and have a number stamped on their flat surface to indicate the height size of the harp.

There are also adjustable harps for a single-socket lamp that is not part of a cluster, and these have a squeezing mechanism that allows you to lock the height in place by sliding the notched harp legs into the short slotted arms of the harp base. You can also get a harp reducer to convert 3/8″ threading on older lamps to the more common 1/4-27F size.

Some table lamps have no harp, and instead, the shade is held in place by a piece of wire shaped like a teardrop. These are called uno assemblies and are most often used on hanging lamps. They are typically made of metal and feature a ring in the center onto which the washer fitter of the shade is slipped. Some uno assemblies have clips that are slid down over the bottom of the harp saddle to hold the shade in place.