Kreg SML-C4X400-75 4-in XL Pocket-Hole Screws - 75 ct. are heavy-duty pocket-hole fasteners made for large stock and stronger joinery. This is a pocket-hole screw designed for fastening 4x4 material and other boards 1-1/2 inches and thicker. Model Number: SML-C4X400-75. If your project has moved past cabinet face frames and into outdoor builds, structural furniture, or big timber-style assemblies, this is the screw Kreg built for that job.

What matters here is scale. These are 4-inch, number 14 hardened-steel screws, so they are built to reach through thick material while giving you the shear strength you need in larger joints. Used with the Kreg Pocket-Hole Jig XL or Kreg Jig HD, they are optimized for pocket-hole joinery where standard screws come up short. For anyone building with 4x4 boards, that extra length is the difference between a joint that merely bites and one that actually holds.

Kreg also engineered the screw geometry for pocket-hole work, not just general fastening. The Maxi-Loc style head seats firmly in the pocket hole, the smooth shank helps draw the joint tight, and the self-tapping tip starts cleanly without forcing the wood apart. In practical terms, that means faster assembly and less chance of splitting when you are driving into large stock.

The drive style matters too. These screws use a square drive and are intended for a number 3 square driver or the Kreg Jig HD driver bit. That setup gives better driver engagement than a loose-fitting recess, which helps reduce cam-out when you are sinking a long fastener into dense material. On a long screw like this, that is not a small detail. It makes driving more controlled and less frustrating.

For outdoor use, the Protec-Kote finish is one of the key reasons to buy this version. Kreg uses a three-layer anti-corrosion coating for long-term moisture resistance, and the screws are listed as ACQ approved and ACQ rated. That makes them a smart choice for many exterior wood projects where exposure and treated lumber are part of the plan. If you are building outside, corrosion resistance is not a bonus feature. It is part of whether the project lasts.

This pack includes 75 screws, which is a practical count for medium-size builds, repairs, or keeping the right fastener on hand for occasional XL pocket-hole work. These are not your everyday shop screws. They are for builders who need the right hardware for thick stock, stronger joints, and outdoor-ready performance without stepping outside the Kreg pocket-hole system.

Who should buy them? Woodworkers, deck and outdoor project builders, remodelers, and serious DIYers working with 4x4 material or oversized joinery. If you already own a Kreg Pocket-Hole Jig XL or Kreg Jig HD and need the correct fastener for big stock, these are the screws to get. If you are working on thinner material, you are better off with a shorter pocket-hole screw instead of trying to make this size do everything.

Why the Kreg SML-C4X400-75 4-in XL Pocket-Hole Screws - 75 ct. earn a spot in the big-stock drawer

If you are building with 4x4s and using the Kreg XL or HD pocket-hole setup, these are the right screws, plain and simple.

• Who it's for: Woodworkers, outdoor builders, and serious DIYers joining 4x4s or other thick stock with a Kreg pocket-hole jig.
• Why it stands out: You get the right 4-inch length, hardened-steel strength, a square drive that stays engaged, and corrosion resistance that makes sense for exterior work.
• Worth knowing: These are purpose-built screws, not general shop fasteners. Make sure you have the compatible jig and a number 3 square driver or Kreg HD driver bit before you start.

• What material thickness are these screws made for? They are intended for 1-1/2 inch and larger stock, including 4x4 boards.
• Are these screws suitable for outdoor use? Yes. They have a Protec-Kote three-layer anti-corrosion finish and are described for indoor and outdoor use.
• What driver do these screws use? They use a square drive and are intended for a number 3 square driver or the Kreg Jig HD driver bit.