Why does my pocket hole joinery ?

[David Eisenhauer]

I used to assemble lots of face frames using pocket screws and found that (as mentioned above by others) I had best success by doing the final screw tightening with a hand screwdriver rather than a powered driver to get the last 1/2 - 3/4 turn or so on the screw. I could feel the screw bringing the two parts into firm-solid-tight contact without overtightening when doing the last bit by hand. This was in a commercial environment where extra steps need to pay for themselves to be effective. The failure rate went to just about zero when doing this. Also, using two screws rather than one per joint makes a world of difference and that was the limiting factor for me when designing the width of my face frame material.

[Lee Schierer]

As others have noted, firring strips are about the poorest choice of wood for pocket hole joint strength. Firring strips are made from wood that is too poor quality to make much of anything else except maybe wood pulp. I use primarily hardwoods in the pocket hole screw joints that I have made. I have only rarely had a screw strip out and those occurred using soft wood. I generally use 1-1/4" screws with the fine threads. I tried some generic brand screws once and they were terrible, so be careful which brand screws you buy. I bought a box of 1,000 Kreg screws and they last a good long while.

[Larry Foster]

Thanks for all of the replies.
I'm in the middle of a 48 hour work/on call weekend.

If I get a break before dark I'll see if I can get a pic of the gate which is where the last failure was.

I talk about the firring strips and the gate but, I've had as much trouble with plywood.

I'll try the last little bit of tightening by hand and see if that makes a difference