Having trouble with pocket holes?

Hey folks, I’m new to pocket holes and kinda stuck. None of the videos I’ve watched explain this problem. I’m trying to attach a 3/4” plywood top to my workbench using a Kreg 720 jig. It’s auto-set for my 1-1/2” frame, and I’ve got my drill bit set to that too. I’m using 1-1/4” screws because I’m going into 3/4” plywood, but the screws aren’t coming through the top of the frame. I also tried 1-1/2” screws, but they just poke through a bit, not enough to grab the plywood. Everything I’ve read says to use the jig and bit setting for the wood you’re screwing into, and the screw length is for the material you’re attaching. So what am I doing wrong here? Should I just use 2” screws and call it a day? Why isn’t this working?

It’s a bit different when your pieces have varying thicknesses. According to this non-Kreg chart, you should use the 1-1/4" setting with 1-1/2" screws.
image

@Chen
Thanks, this really clears things up. Saved it for future use!

Rowen said:
@Chen
Thanks, this really clears things up. Saved it for future use!

I’m using the Kreg 720 that auto-adjusts. I guess next time I should try one that’s not self-adjusting. For now, I’ll try using 2” screws since I’ve already drilled the holes.

@Rowen
Why is your pocket hole so low on the 2x4? Are you sure the wood is pushed all the way into the jig?

Joss said:
@Rowen
Why is your pocket hole so low on the 2x4? Are you sure the wood is pushed all the way into the jig?

Yep, I double-checked it. The pocket holes I made in the 2x4s for framing are at the same distance. It just looks off because of the angle.

@Chen
Is there a metric version of this chart?

@Chen
I have this printed out in my shop. Super handy!

@Chen
Why are there two numbers in each square on the chart?

Hayden said:
@Chen
Why are there two numbers in each square on the chart?

The top number is the jig setting, and the bottom one is the screw length.

Chen said:

Hayden said:
@Chen
Why are there two numbers in each square on the chart?

The top number is the jig setting, and the bottom one is the screw length.

Thanks for clearing that up!

@Chen
Nice chart!

You’ve set it right for 2x (1-1/2”) lumber, but the assumption is that both pieces are 2x material. Since you’re attaching to 3/4” plywood, you need a shorter screw. 1-3/4” screws don’t exist, so 2” should work. Test it on scrap first. If it pokes through, adjust the stop collar on your bit by 1/4” so it doesn’t drill as deep. Or you could set everything for 3/4” and use 1-1/4” screws, but the screw won’t come out in the center of your 1-1/2” frame.

You’re supposed to set the jig for 3/4”, not 1-1/2”. If you set it for 1-1/2”, the screw will come out in the middle of the 2x4. Try setting it for 3/4”, and that 1-1/4” screw should work fine for the plywood.

@Luca
The Kreg 720 auto-adjusts and doesn’t allow manual changes. I may need to try a different jig.

Rowen said:
@Luca
The Kreg 720 auto-adjusts and doesn’t allow manual changes. I may need to try a different jig.

You don’t need to change the jig. It’s the stop collar on the bit that you need to adjust.

Rowen said:
@Luca
The Kreg 720 auto-adjusts and doesn’t allow manual changes. I may need to try a different jig.

You could cheat by putting a 3/4” block of wood in the bottom of the jig. Adjust the stop collar on your drill bit to 3/4” as well. Normally, you’d use 2-1/2” screws for 2x material.

This is one of those times when keeping scraps for testing really pays off. You can try different screws and settings without messing up your project.

Try using the Kreg Screw Selector. It’s a great tool.

You set the jig based on the thickness of the wood you’re drilling into, not what you’re attaching it to. Since you’re going into a 1-1/2” frame, you could use 2” screws.