If it is a digital from the 40's, don't try. Barr digital clocks are somewhat uncommon and even more uncommon in good working order. Barr's mechanism was unique. The wheels were metal and they interlocked via gear teeth on the inside of the wheels. If you dissemble a set of Barr wheels, be prepared to spend an evening trying to reassemble them in proper orientation. Even with proper assembly, the Barr mechanism had difficulty positioning the facets of the wheels so the numbers lined up properly. Russ.
NAWCC Watch and Clock Bulletins are one of the many benefits of NAWCC Membership.
The "Bulletin" is the Magazine published six times a year by NAWCC for members. The article on the Poole battery pendulum clock is just one of many articles in the August 1998 Bulletin about clocks and watches. All NAWCC Bulletins published since 1943 are archived and available in dot pdf format instantly on your own computer screen but only for NAWCC members.
Because the contents of NAWCC Bulletins are copyright by the author and NAWCC, I would be uncomfortable in providing the seven pages pertaining to the Poole battery pendulum clock to you. However, I have copied a page from the author's article on the Poole clock and added it to this post as an attachment.
The "Bulletin" is just one of the many benefits afforded to members. Message board subscribers are encouraged to join NAWCC.