Correct Screw

[Scott Brubaker]

What is the correct size and thread Kreg screw to use when screwing a 2"x4" onto a 3/4" sheet of MDF plywood.

[Ken Darga]

Here are some links, posted in the Kreg Community Forums.

http://kregjig.ning.com/photo/image-screw-chart-size

http://kregjig.ning.com/photo/002-23

http://kregjig.ning.com/photo/kreg-screw-selection-1

[Ken Darga]

I don't feel you achieve a solid connection, driving the screw into MDF.

A stronger joint will be achieved if the screw threads engage into the 2x4 stock.

See if you can change your design plans, to accomplish this task.

[KregRep]

When it comes to joining materials of different thicknesses, it’s a good idea to test screw length. Do this by drilling into a test piece(s). The typical rule is as follows: Set your Kreg Jig for the thickness of the material you are drilling the pocket hole in. Then, choose screw size based on the thickness of the mating piece the screw will be entering into. The Screw Selector Wheel will help you identify the correct screw length and jig setting.

[Scott Brubaker]

Thank you for the responses everyone.  I'll do some trial and error using the provided documents as guides.