Nicholson Plumb Level - by Rick M. @ LumberJocks.com ~ woodworking community
This is a modernized reproduction of the plumb level as drawn in Peter Nicholson’s The Mechanics Companion, 1831.
My version replaces the string and lead weight with a brass rod, attached to a wood axle press fit into a roller bearing. The frame is cherry, the plumb bob is ebony, the inlay strip is American holly, finish is beeswax and oil. There is no advantage to the rod and bearing, I did it simply to modernize the design and be different. I would show a picture of the bearing in place but after pressing in the axle I couldn’t remove it. The brass rod is actually canted back toward the frame and the plumb bob is flat on the back. On a level surface the pointer will be centered on the white strip. Gravity will push the pointer toward the low side. The bearing is a 1/4×3/8×1/8” metal shielded bearing that is press fit into a hole drilled top center. The ebony axle has a small tenon on the back that fits into the bearing. It works like a plumb bob, gravity forces the pointer toward earth and when aligned with the holly strip the base is level.
Plumb levels have been around for at least 4500 years. They were used by Egyptians to build pyramids and the Romans used variations for surveying and construction. Many variations existed.