What Size Screws Do I Need For Pocket Holes?

Pocket screws have been used for a long time, with one instance of pocket hole joints reportedly used on a table dating back to 1840.  

You can use pocket hole joints to join 2 pieces of wood together in just about any configuration:

  • End to edge
  • End to face
  • Mitered 

Or any other way you can think of for your projects.  The uses of a pocket hole joint are virtually unlimited and are common, for instance, in structural frames and cabinet face frames.

Pocket Hole Joinery: Strong, Easy, and Quick

These joints are strong, too, and that strength has been proven in independent testing.  Pocket screw joints were found in one test to fail at 707 lbs when subjected to a shear load, while a similar mortise and tenon joint failed at 453 lbs.  This represents a 35% stronger joint and thus the wide use of this joinery technique.

Besides being strong, the appeal and main advantage of pocket hole joinery over other methods is ease and speed – – it’s easy, and it’s quick.  Pocket holes can be drilled, and pockets created for screws on your own by hand, but this is one exercise where a jig is far more accurate.

First coming into use in 1986 by Craig Sommerfield, a tool and die, maker, it came in handy for him when he was building a home and needed something to help attach face frames to his cabinets.  His wife had asked that all holes be hidden in their home’s cabinetry, and the jig was created.

The first name in pocket hole jigs today is Kreg, the company Sommerfield founded when his jig began selling well at woodworking shows.  His wife had asked that all holes be hidden in their home’s cabinetry, and the jig was created. It’s been used by carpenters and cabinet/furniture makers ever since.  The Kreg Tool Company today generates more than $60M in sales.

Kreg KPHJ720PRO-21 - Kreg Pocket-Hole Jig 720PRO with 3" Automaxx Clamp & Screws - Easy Clamping & Adjusting - For Materials 1/2" to 1 1/2" Thick
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The pocket hole jig guides a drill bit at the right angle and to the right depth by setting the adjustable depth guide, and can be quickly moved along the board being joined for repeated cuts.  Once the holes have been drilled, the screws are guided into the holes, and it’s simply a matter of choosing the right screw size and type.

How Long Should Screws Be For Pocket Holes?

The length of the screw you use for pocket holes will depend on the jig setting and the depth of the drilling, each of which will depend on the boards being joined.

As a general rule, screws should reach at least half of the thickness of the bottom board.  Kreg jigs do come with a manual filled with charts that will suggest the right depths for various joinery tasks.

There are 4 common thread lengths most commonly used, and they are 1”, 1 ¼”, 1 ½”, and 2 ½”.  Again, the length of the screws you use will be determined by the depth of the drilling, and the depth of the drilling depends on the boards being joined.

Kreg SK03 Pocket-Hole Screw Kit in 5 Sizes

For example, when joining 2 x 4 boards, where the actual dimensions are 1 ½’ and 3 ½”, you would choose the 2 ½” screw length for the strongest joinery.  

Another example is when joining 1 x 4 lumber.  Remember that the actual dimensions will be ¾” by 3 ½” for this lumber, as it affects the screw you choose.  For this joinery, you’d choose a 1 ¼” screw, according to the Kreg chart.

Pocket Hole Screw Size Chart

Wood Thickness (inches)Screw Length (inches)
1/21 1/4
5/81 1/4 – 1 1/2
3/41 1/4 – 2
7/81 1/2 – 2 1/2
11 1/2 – 2 1/2
1 1/82 – 2 1/2
1 1/42 – 2 1/2
1 3/82 1/2 – 3
1 1/22 1/2 – 3
1 5/82 1/2 – 3
1 3/42 1/2 – 3
1 7/82 1/2 – 3
22 1/2 – 3

Here’s a video that will help you ensure the right length of the screws you choose for your pocket holes.  It’s from Kreg, even.

And a second: 

And a third: 

How Do You Size Pocket Holes in Woods?

When you’re joining workpieces of different thickness, the generally accepted rule is to think thin.  When you set up the drill guide, the drill depth collar, and choosing the right screws for the different thicknesses, you should set it up to join the thinnest piece you are working with on your project.

Does the Wood Matter in Choosing Pocket Screws?

Pine, cedar, fir, and spruce, for instance, are softwoods, soft and not very dense.  Plywood and MDF (medium density fiberboard) would fall into that same category when it comes to choosing pocket screws. The washer heads will help prevent overdriving the screws when you are joining particle board and plywood.   

You’ll want deep and aggressive threads on the screws to dig into those soft fibers.  Coarse-thread screws are the ones you’ll want to be using when working with softwoods.

Hardwoods like oak, maple, walnut, and cherry, are too hard for coarse-thread screws.  They’ll tear the fibers and lead to splits in the wood.  Choose a fine-thread screw for joining them.

Pocket Hole Jig

The Kreg Tool Company makes screws for its jigs.  Most woodworkers will choose to use the screws Kreg makes for its own jigs, and follow the charts that come in the jig manual.

In fact, most will recommend using Kreg’s own screws.  They are specially designed and made to work with the holes drilled using the Kreg jig.  

If you insist on using regular screws instead of Kreg’s screws, you can.  But, the Kreg screws have an especially sharpened point that makes it easier to burrow into the second piece of wood to be joined.  You must remember that the drilled hole will not extend into the second piece, so this becomes important in forming a strong joint.

Should You Glue Pocket Holes?

It’s never a bad idea to take a belt-and-suspenders approach when you can.  If you’re building a beautiful dining room table for your home and family, a bit of glue will give that little extra holding power to keep the joint from separating.  

The choice of whether to invest in a pocket hole jig depends on the types of projects you’ll be tackling.  As we always say, the right tool for the right job.  But, if your projects are going to include cabinets and tables, or even shelves, anything with multiple joints, a jig is a worthy investment.  You can’t do better than to choose from the Kreg line of jigs.

From the Kreg Mini, at $15, to the Jig XL at $60, to the Pocket Hole Pro at $150, there are many models to choose from that can be budget friendly to your needs and help you on your projects.  If you’re going to invest in a Kreg jig, you might as well use the Kreg screws that are designed to work best with it, too. 

Kreg KPHJ310 Pocket-Hole Jig 310 - Small, Durable Jig for Tight Spaces - Create Perfect, Rock-Solid Joints - For Materials 1/2" to 1 1/2" Thick
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Keep your wife happy by hiding the holes just like Craig Sommerfield did back in the 1980s.

Last update on 2023-09-28 / Affiliate links / Images from Amazon Product Advertising API

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