Christopher Orchard’s

GRASSHOPPER SKELETON CLOCK

This fine clock by Chris Orchard was photographed at the Midlands Exhibition in 2013. It is his version of the Bill Smith design for a grasshopper escapement clock.

The grasshopper escapement was invented by John Harrison around 1722 and used in his clocks designed to determine longitude at sea. Since that time it has been rarely used, despite the fact that it has low friction and so shows little wear ever after centuries of running, in some original Harrison clocks. The term ‘grasshopper’ comes from the action of the escapement.

Bill Smith’s design brought the grasshopper to attention of model engineers and an example can usually be seen at larger exhibitions. It was first published Model Engineer magazine, unfortunately with a number of omissions which were never fully recovered. So he put the complete material, including drawings, into a comb-bound book which is normally available from the usual suppliers of clock books for model engineers.

The escapement is fascinating to watch. The pivoted pallets literally pick their way around the escape wheels. It employs two escape wheels rather than one resulting in a more compact arrangement which does not leave open spaces and allows attractive proportions  with  the reduced height of the clock.