Around here everyone uses a spud bar or tamping bar to add pressure to the PHD.
It also seems to me that if you are trying to run too high an RPM you will be more likely to spin round and round without biting, than you will by runnign lower RPMs and adding pressure to begin cutting.
It also seems to me that if you are trying to run too high an RPM you will be more likely to spin round and round without biting, than you will by runnign lower RPMs and adding pressure to begin cutting.