(D)W5 - Free Pendulum Clock

Perhaps the first advancement in mechanical horology in 100 years was introduced by Philip Woodward, British mathematician, radar engineer and horologist. His W5 clock featured a mechanism in which a free pendulum is impulsed by a dropped weight timed by a slave pendulum. The rate of the slave pendulum is regulated by the rate of the free pendulum through a feedback mechanism. If it sounds complex, well, it is. But it provides one of the most fascinating and intricate timekeeping mechanisms anywhere.

Making it more precise

David Walter took Woodward's concept to the next level. He added jeweled bearings, tungsten-carbide knife-edge suspension, barometric compensation on the pendulum bobs, and fused silica (quartz) pendulum rods. With a distinctive glass dial and spectacular skeletonized movement, and you end up with an extremely accurate timepiece that can't fail to attract attention and admiration.

Philip Woodward, inventor of the movement, provided invaluable assistance to David during this clock's development. In recognition of this, David kept Woodward's W5 designation, adding the (D) to form his own initials as well.

The escapement in action

This video depicts a "hit" (impulse) in the escapement.

Additional videos (will open in new window)

• A "miss" in the escapement
• The miss in slow motion
• The hit in slow motion

Videos courtesy of Mike Everman

(D)W5 in print

The prestigious magazine of the British Horological Institute, Horological Journal, published an extensive article on (D)W5. Click the link below to view it.

Horological Journal - (D)W5, a Free Pendulum Clock (PDF)

English Brown Oak case, with Ebony inlay - oil finish

Flame Mahogany with Rosewood crossbanding and hand shaped semi round brass inlay to the glazed portion, flat brass to the backboard and special brass lower finial case- French polish

Detail

Burl Walnut with Boxwood inlay, crossbanded with Burl Walnut case - French polish