I was taught and it has been my experience to not attempt to clear the chips while boring a mortise. The spiral twist of the bit should clear the chips to the surface of the timber, even in oak.
Once a bit has started it path to the bottom of the mortise, it should not be stopped and removed to clear chips for the mentioned reason "you have to get the screw tip restarted in the hole."
Using a boring machine with the proper sized bit for the mortise is the key.
Once the bit has reached the bottom of the mortise the handles of the boring machine are turned in reverse to "back out" the lead screw tip from the thread it has created in the bottom of the mortise. This turning in reverse one full revolution of the handles will back out the tip and then you engage your lifting mechanism to lift the bit and all current chips out of the hole.
We recently repaired a shear pin on a boring machine due to the operator not understanding this procedure (or old age of the worn shear pin).
Understanding how to use this tool is important.



Hope this helps.

Jim Rogers