Are they Oak chips (more than likely) or cubes?
Chips extract faster than cubes so they are done by the end of secondary Day 22 aprox. I always transfer pretty much everything to secondary (including chips) at around 1.0 and then let it sit for ~ 12 days to let it go to 0.996 or dry. That gives the wine enough time to finish all the oak extraction.
At that point, rack off the oak and lees and stabilize, fine, degas......