Yet another balk question

[harmbu]

I hope my description is easy to understand:

While working from the windup a pitcher stands on the rubber facing the plate with his hands apart. Without moving his feet, the pitcher brings his hands together in front of him. After a few seconds he steps back, completes his windup and pitces.

My question is once he puts his hands together can he step off if a runner breaks for the next base? Or would moving his hands be considered the start of his windup?

Please give the Fed ruling for this play.

Thanks in advance.