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

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)

This is part 3 of a three-part series about Derek Pratt’s reconstruction of John Harrison’s Longitude Prize-winning H4, which was the world’s first precision marine chronometer. This article was first published in ‘The Horological Journal’ (HJ) in April 2015, who we thank for graciously granting permission to republish on Quill & Pad.

A finished diamond pallet beside a match head for Derek Pratt's John Harrison H4 reconstruction

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)

Here we present the second part in a three-part series about the making of Derek Pratt’s reconstruction of John Harrison’s H4. This part was written by Carl Murray of Frodsham. This article was first published in ‘The Horological Journal’ (HJ) in March 2015, who we thank for permission to republish on Quill & Pad.

Reconstruction of Jhon Harrison's H4 by Derek Pratt, which was finished by Frodshams (image courtesy British Horological Journal)

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

Here we present the first part in a three-part series about the making of Derek Pratt’s H4 reconstruction. This part was written by Roger Stevenson, chief watchmaker at Frodsham. This article was first published in the ‘The Horological Journal’ (HJ) in February 2015 and we thank them for the gracious permission to republish it on Quill & Pad.

The rear view of the Urban Jürgensen oval tourbillon pocket watch from 1991 by Derek Pratt reveals the remontoir tourbillon with spring detent escapement; this movement is wound by key

The Life And Times Of Legendary Independent Watchmaker Derek Pratt

Derek Pratt (1938 – 2009) was perhaps one of the most “complete” watchmakers of our time along with his friend George Daniels. The Swiss-based Englishman firmly was behind and part of many watches and projects that are today common knowledge, while his own name remains relatively hidden.