Here is an early example of single comb construction, of academic
interest for those who enjoy the early cylinder musical box.

Not many fully appreciate how or when comb construction changed
from sectional comb to a single comb, but the man who bossed this
process was François Nicole.  When the other makers were generally
using groups of four teeth, he was on a mission.

On this video of a François, hosted on the MBSGB channel, we can
see what appears to be a single comb construction but is actually
composed in three pieces, with the four extreme bass teeth bolted on.
Overall there are 21.7 teeth per inch.

  https://youtu.be/8OcL0DBXc1c 

Mark Singleton
http://www.mbsgb.org.uk/