Screw size for DIFFERENT sized lumber

[Steve Gronsky]

I seem to recall from a previous post somewhere that when choosing your screw size you should select the screw for the "receiving" piece of lumber rather than for the drilled piece.

e.g.  when joining a 2x4 to a 3/4 thick piece you should use the 1 1/4 inch screw.

as opposed to joining 2 2x4 to each other - you would use a 2 1/2 inch screw.

Have I got this correct? 

[Ken Darga]

Probably preferred to use the paper chart---laminated it or put into a plastic bag, and kept it with his Kreg tool box. 

Paul Jones said:

No it's not a copy, someone didn't need it and sold it
I guess

[Joe]

Thanks for this question. I want to join 3/4 inch 18 inch square  Baltic Birch plywood together at a right angle. If i put a 3/8 inch rabbet in one piece what size screw would work and will I get a stronger joint? 

[Donald Wilton]

This is great information! Thanks

[Geno Parmentier]

What happens if the thinner piece of wood is your table top and you don't want to have pocket holes in table top?  For example, I have 4 2x4's creating a frame and place a plywood board on top of that for table top which is 2 inches thick.   

[Joe Thomas]

Here's a PDF document I've created with the same screw settings as the other document, but this one has the X and Y axes labeled. It's still important, though, to test on scrap pieces first! I've tested some of these, and they work great, but I haven't tested them all.

[Peter DeGregorio]

The PDF is surely helpful but it has some mistakes in it e.g. obvious ones on the 7/8" row  so I bought the Kreg Screw Selector Wheel ($4 off list at my local Woodcraft store) and compared it the chart and there are a quite a few  conflicts between it and the PDF. Not sure if the differences matter but wanted to add this info to the record.

Dan said:

I don't quite remember who originally postedd this, but it may help when deciding which screw size to use. I believe the sizes outside the grid are the "whole" pieces and the sizes inside the grid are the "screw into" pieces.

[Joe Thomas]

Thank you, Peter DeGregorio. Yes, I just received the Kreg Screw Selector Wheel from Amazon, and I'm seeing some differences. I used to use the PDF because I couldn't find the Kreg Screw Selector Wheel anywhere. Now that it's available on Amazon, people shouldn't have issues.

[Robert]

The vertical numbers on the left are what you would drill the pocket hole in. The horizontal numbers on the top are the thickness of the wood you will be fastening to. I laminated this to hang on my shop wall for easy reference.

Dan said:

I don't quite remember who originally postedd this, but it may help when deciding which screw size to use. I believe the sizes outside the grid are the "whole" pieces and the sizes inside the grid are the "screw into" pieces.

[Cathy Bradford]

Thanks!!  Great information!

Joe Thomas said:

Here's a PDF document I've created with the same screw settings as the other document, but this one has the X and Y axes labeled. It's still important, though, to test on scrap pieces first! I've tested some of these, and they work great, but I haven't tested them all.