Movement for a month going regulator manufactured by Jones & Chambault to a unique design submitted by Boodle & Dunthorne

The massive six pillared movement features two mainwheels fitted with ball bearings on their winding arbors, gearing into the going train.

Two 15lb weights power the going train which has 12 leaf pinions throughout and is fitted with an adjustable Graham deadbeat escapement.

The motionwork is conventional but note the long hour and minute wheel pipes which provide enough room behind the dial for the complicated perpetual calendar work (not shown).

The centre arbor and motion work had to be made with great accuracy so that they had as little effect as possible on the time keeping of the regulator. Backlash in the motion work also had to be minimized so that the hands would indicate the correct time.

The pendulum features a conventional cylindrical bob on an invar rod. For an unjewelled regulator without temperature compensation it has an excellent time keeping performance.