Back in 2017 we ran an interesting three-part series chronicling the making of Derek Pratt’s H4 reconstruction by Roger Stevenson, chief watchmaker at Frodshams. These articles were first published in the The Horological Journal (HJ) in February 2015 and we thank them again for permission to republish here on Quill & Pad.

Derek Pratt’s H4 reconstruction showing the completed movement and Charles Scarr’s piercing and engraving

I thought it well worth drawing your attention to this series once again in case you missed it the first time around.

To see each incredibly researched and richly illustrated part of the series, click the links below.

Derek Pratt’s Reconstruction Of John Harrison’s H4, The World’s First Precision Marine Chronometer (Part 1 of 3)

Making The Diamond Pallets For Derek Pratt’s Reconstruction Of John Harrison‘s H4, The World’s First Precision Marine Chronometer (Part 2 of 3)

Making The Escapement, Remontoir, And Timing For Derek Pratt’s Reconstruction Of John Harrison‘s H4, The World’s First Precision Marine Chronometer (Part 3 of 3)

You can buy a DVD of the film about Derek Pratt’s H4 reconstruction at www.bdvideos.co.uk/site/shop/horology/a-detailed-study-of-h4/ (all profits go to the charity Prostate Cancer UK.)

For more information, please visit www.frodsham.com/harrison-h4.

You may also enjoy:

The Life And Times Of Legendary Independent Watchmaker Derek Pratt

Burgess Clock B, The World’s Most Precise Pendulum Clock, Is Made To A 250-Year-Old Design By John Harrison, Longitude Prize Winner And Inventor Of The Marine Chronometer

Discovering The Secret Of Life With David Walter: Watches, Clocks, And DeeDee’s Tourbillon

Struthers & Co. Watchmakers’ Project 248