A local thrift store had a box of desk and wall lamps for $1 each. This one had a round base, hung on the wall and pivoted up and down. Useful, but too short for task lighting. So I trashed the base and built an arm that would reach my grinder on one side and band saw on the other. The individual arm segments are 1/2" thick and 1-1/4" wide.
Two shots of the hub, turned from scrap pine. The tenons on each end are slightly smaller than 1". At first the bracket was all one piece but got in the way and stopped the arm from swinging all the way left. So I cut the bracket in half and reversed each piece as you see below.
I started with a 200W incandescent bulb that made a very bright task light but melted the plastic! So I switched to a 13W compact fluorescent (equivalent to a 60W incandescent). Next trip to the store I'll pick up a brighter one.
See the silver clamp light over my lathe, another $1 special.