Replicas and Restorations of Early Instruments by Richard A. Paselk

Richard Paselk, Curator

The Navigator's Quadrant

The quadrant was one of the earliest navigator's instruments, with the first documented use in the mid 1400's. It was probably the first instrument provided by the astronomers and mathematicians that Prince Henry the navigator had gathered to help with the Portuguese exploration of the west coast of Africa. unfortunately it was not very effective on board ship with the plumb bob swinging around with ship movement.

I made this piece from some 1/2' thick ash wood in a broken piece of furniture I recovered about 1976. The piece was large and flat enoough that I could use it as a single piece without gluing up small pieces. I initally cut a square with a table saw, then drew a curve with a large compass and cut the radius a bit oversize with a band saw. I them used an old Staley compass plane to shave the outer radius down to the compass drawn radius. Both sides of the wood were then sanded smooth and a piece of "parchment" paper was glued on to the top surface. After using an ink compass to draw the quarter-circles for the scales, the figures etc. were written in with black ink.Two small pinnules were made from 14 g brass for the sites and a plum bob was turned from brass rod on a lathe using files to shape the metal.

© R. Paselk 2013, Last modified 26 December 2020