Everyone knows the problem of pieces moving from their proper positions when joining them with Kreg pocket hole screws. To avoid it, I simply insert the screws before joining the pieces and drive them into the drilled pocket hole so that the very tip of screw is slightly out. Then, I put two pieces together and the tips of screws from one piece “bite” slightly the other piece like pins. This helps me to keep the joint in position when tightening these screws.
– Sergey Bocharov