Here's a brief breakdown to help answer some of the most common lamp hardware questions.
HARP: The harp is tall piece of hardware that attaches the shade to the base of the lamp. Harps come in different heights for different size shades. Harps are available online in one inch and half inch increments. If you are interested in changing the height of your lamp or the shape of your shade, this is the best place to start.
FINIAL: The finial screws on to the top of the harp and stabilizes the shade. Finials come in endless styles and finishes. They can easily be changed to freshen up the look of your lamp.
SADDLE: The saddle is a small piece of hardware attached to the lamp base underneath the socket where the harp is clicked in. If a lamp doesn't have a saddle, a slip uno adapter can be used instead to secure the harp to the lamp base.
ADAPTERS: An adapter is a piece of hardware you use to modify your lamp allowing it to use a shade that it wasn't originally designed to use. For example, many European lamps use UNO RINGS rather than SPIDER RINGS. With the use of an adapter, a spider ring shade can be used on these lamps. This is a simple and cost effective alternative to rewiring the lamp with different hardware. Here are the two most common adapters:
An UNO SLIP ADAPTER is a modified saddle that allows you to use a harp and spider ring shade on your lamp. This adapter is best for lamps that need medium to large shades, and any height harp can be used with this adapter.
A CLIP-ON ADAPTER clicks onto the lightbulb and allows you to use a spider ring with a finial to secure the shade. This adapter works best for small lamps, and especially for shades that are too short to use a harp. Since the height of a clip-on adapter cannot be adjusted, it is advised that you test the hardware with your preferred light bulb to determine the proper shade height for your lamp.
RINGS: The rings refer to the shade hardware that creates the framework of the shade and allows it to attach to the lamp base. There are many types of lamp shades, so for simplicity's sake, I will only be talking about rings for hardback lamp shades. I will create a post in the future talking about different lamp shade types.
SPIDER RINGS are the shade hardware that is most common in the states. The top of the lamp shade has spokes that meet in the center at a washer (small ring). The washer in the center of the shade rests on the harp and then a finial is screwed on to the harp to prevent the shade from wobbling.
The washer is set in to the center of the shade. This is called THE DROP. The industry standard for a spider drop is 1/2". That means that the washer is 1/2" lower than the top of the shade. This inset allows for the hardware and finial to be slightly obscured from view at eye level. it is common for larger and vintage lamp shades to have much larger drops.
UNO RINGS, or EURO RINGS as they are sometimes called, also have spokes, but have a larger ring in the center that is designed to slip over the lamp's socket and is often threaded on. The spokes can come from the top or the bottom rings, and these shades often have a much larger drop than 1/2". In my personal experience, I haven't seen a 'standard' drop for uno rings as the goal is the get the light bulb to rest in the middle of the shade. This is a much more custom option that varies per lamp design.
Have a question? I know this includes a lot of terminology that we don't use in our day-to-day lives. If you are confused about any of this information or have a question specific to getting the right shade on one of your lamps, please feel free to reach out through my Contact Page. I'll email you within a couple days. I'm happy to help. -Krista