8-32 Side Hole for thumb screw (#3645 thumb screw sold separately)
Brass Lamp Couplings are a simple threaded brass sleeve enabling two pieces of lamp pipe to be connected. Joins two 1/4 IP size pipes together or can slip 1/8 IP. Use thumb screw in side outlet hole for added security.
Standard Lamp Thread Sizes
Standardized thread sizes for lamps enable many types of parts to be connected. It is imperative to know the thread size when replacing any antique lamp parts. List of common lamp threads and there uses provides a quick reference.
F: designates a female thread - part is tapped having interior threads.
M: designates a male thread - threaded with exterior threads.
IP: Standardized lamp pipe sizing designation
8-32 - 5/32" outside diameter, used as holder screws with some glass shades.
1/4-20 - 9/16" outside diameter
1/4-27 - 7/32" outside diameter, used on harp posts & most lamp finials.
1/8 IP-27 - 3/8" outside diameter, very common thread used on table lamps, socket caps, and some finials. Allows electrical wire to pass through pipe.
1/4 IP-18 - 1/2" outside diameter, used on floor lamps, clusters, ceiling fixtures, and floor lamp bases.
3/8 IP - 5/8" outside diameter, used on chandeliers and hanging lamps.