Wood movement question

[Ken Miller]

Does attaching a desktop using kreg pocket holes allow for wood movement? If it matters, the top is cherry and the base is a combination of painted poplar and plywood. Also, in glueing up boards for a 28" wide desktop, is there a recommended board width? I was thinking of using about 5" or 3" boards. Thanks in advance.

[Peter Quinn]

I think you can use pocket hole screws but you will need to enlarge the pilot that the bit makes. A pocket hole screw with its hole as created by the bit is designed to resist wood movement, not accommodate it. Think face frame but joints or face frame to carcass connections. You don't want these joints to move, and that is what pocket screws excel at. You must over size the pilot screw with a separate bit, perhaps to a #10 or #12 pilot screw for a #7 pocket screw. It would not be my first choice for a desk top that big, and I think you should avoid using them across the length as this will constrict the tops movement at its widest point.