The carpenter who built clocks with wooden wheels, and then solved longitude

A self-taught village carpenter, a clock of oak wheels, and the wood that needed no oil.

By Made Over Weekend · 3 min read

John Harrison was born in 1693 and made his first clocks in Barrow upon Humber, a village in North Lincolnshire. He was a carpenter by trade. He had no formal education in clockmaking. With his brother James he taught himself to mend clocks, and then to make them.

In 1713, when he was just 20, he finished his first longcase clock. It is now in the Science Museum Group collection, and he signed it in ink on the calendar wheel: "Jon Harrison 1713". The museum record says the frame and most of the wheels are made of wood. A second movement followed in 1715, when he was 22.

By the mid 1720s the brothers were making precision longcase clocks that Royal Museums Greenwich says kept time to within one second a month. That skill led Harrison to the great problem of his age: keeping time at sea, so sailors could find their longitude. His first sea clock, H1, was brought to London in 1735 and tested at sea in 1736. Decades of work followed, and in 1765 the Board of Longitude recommended a payment of 10,000 pounds. He died in 1776.

How it was built

The 1715 movement shows how a carpenter thinks. The frame and the wheels are oak. The pinions, the small gears that the wheels drive, and the arbors, the axles, are boxwood, a dense and even wood. Only the pivots and a few parts are steel and brass. The Science Museum suggests he worked in wood partly because he was a carpenter, and partly, it is thought, to reduce the need for oil.

In his clocks Harrison used lignum vitae, a very dense tropical wood full of natural oil. Australian Wood Review notes that this wood required no lubrication.

What it teaches a weekend woodworker

Harrison did not use one wood for everything. He matched each wood to its job: oak for strength, boxwood for small fine parts, lignum vitae where parts rub. You can use the same thinking at home. For a drawer or a sliding box lid, pick a hard, close grained wood such as maple or beech for the runners, and keep soft pine for the parts that just hold things. Instead of oil, rub a little paraffin wax or a plain candle on the sliding surfaces. Wax does not soak in or collect dust the way oil does, and the drawer runs smooth.

A small box with a sliding lid is a perfect weekend test. Cut the grooves, pick a good wood for the lid, wax it, and feel the difference.