The Wood
The properties that make a wood suitable for wooden clock construction are :-
Medium to Hardwood
Fine grained
Retains detail when machined and sanded
Resists splintering
Low distortion after machining
The woods listed here would all be suitable for the construction of a wooden clock.
Apple
Beech
Birch
Boxwood
Cherry
Holly
Hornbeam
Maple
Pear
Sycamore
Tupelo
Walnut
Sources of information
I have not mentioned any sheet type materials here because I have a feeling that it would not be right to encourage anyone to spend so many hours building a complex mechanism like this only to have its aesthetic ruined by the use of plywood or MDF. These materials have their place, and if using a machine to cut the profiles then it could be beneficial to do a trial run using a sheet material.
Obtaining real wood in the right sizes can be difficult, but it should be encouraged because the finished result is so much better.
A possible source for wood blanks suitable for making the clocks is the suppliers of wooden flooring. They have strips of hardwood that can be fitted and glued together to form blanks in a wide variety of sizes and wood types.
The Hardwood Floor Store shown opposite is a typical example of this type of resource.