This tool does not have a countersink adjustment and I think the countersink is too big and too deep, at least for the #8 screws I bought (GRK Fintrim). When mine arrived I noted on the packaging that it was specifically designed for Headcote and Deckfast bolts - as also stated on their website (retrospectively). Here is my workaround. I dug around and found an electroplated strap with several 1/2" holes (slightly smaller than the diameter of the depth gauge on the tool. about a penny thick). I just center the 1/2" hole in the strap over the desired screw position and let the depth gauge hit the metal instead of the wood.Much better result for my self tapping screws.