A lampshade spider fitting connects a lampshade and lamp base together through the use of a harp, saddle and finial. Knowing if you require a lampshade with a spider fitting is important when purchasing a new shade for your lamp.
Spider
A lampshade spider consists of metal arms that attach to the inside top rim of the lampshade and join in the center to a hollow round metal disc that looks like a washer. Spider fittings are also called "washer fittings."
Harp
The harp is a "U" shaped piece of metal. The two ends of the harp slide into a saddle, which is a bracket attached to the socket of the lamp base.
Finial
The finial attaches the harp and the shade together. A screw attached to the top of the harp pushes through the round central piece of the spider, and the finial threads onto it, securing the shade to the harp.
Necessity
If your lamp base has a harp and finial attached to it, or a saddle affixed to the socket of the lamp that the harp slides into, you will require a shade with a spider fitting.
Tip
Two additional types of lampshade fitters include clip fitters and UNO fitters. Both of these types allow the lampshade to attach to the lamp without the use of a harp and finial.
Amy Swanton Mills
Amy Swanton Mills is a writer and designer residing in Los Angeles. She has spent the past 10 years working in various aspects of the architecture, furniture and interior design industry. Her articles on furniture, design and green lifestyle issues regularly appear on eHow.com and furnicology.com. She earned a Bachelor of Arts degree in English and History from UCLA.