There have been multiple threads here about chess clocks for pool. Below is part of one of those threads about using them for 14.1. It is possible to use them for by-the-rack games such as 8 ball and 9 ball. Chess clocks have worked for pool already.
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This has been discussed several times before. Many of the posters to this thread don't understand how modern chess clocks work.
I figured out how to use chess clocks for pool after a league match to 100 at straight pool took three and a half hours. It worked like this:
Each player gets a starting bank of 30 seconds per ball needed plus 10 minutes for overhead.
The clock adds an additional 20 seconds per inning. That means that if you play briskly a safety exchange costs you no time.
When a player finishes his turn, he has to go over to the clock which is between the players' chairs and start his opponent's clock. For chess clocks, only one player's clock runs at a time. That gets the non-shooter away from the table as a side benefit.
If there is interference from outside or a rule needs to be decided, the clocks are suspended.
Rack your own on your own time. Take as long as you want to rack the balls. It's your own time.
Need a bathroom visit? Do it on your own time.
Need five minutes to decide on a safety? It's your own time, but you better play fast otherwise.
The penalty for running out of time was that your opponent got pro-rated points according to how much time was left on his clock. If he had 20 minutes left, he got 40 balls. That was at straight pool. For rack-based games you could do something similar or simply give a separate time for each rack. As it turned out, no one ever ran out of time. 30 seconds per ball is plenty. The pressure from the clock was sufficient to make the snails move it.
A huge advantage over the traditional shot clock is that no operator is needed. You could have all matches on the clock with no additional staff.
In Europe chess clocks are routinely used for billiard matches in league play.