Skip to content
Shop Your Local Store ● Ship to Your Hometown Store
Pro & Contractor Accounts ● Apply for Net Terms
100,000+ Products ● Trusted Authentic Brands
FAQ Shipping & Returns Order Lookup Contact Account
SPAX PowerLags 5/16 in. in. X 6-3/4 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 6-3/4 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 6-3/4 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 6-3/4 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 6-3/4 in. L T-40 Washer Head Serrated Structural Screws
SPAX PowerLags 5/16 in. in. X 6-3/4 in. L T-40 Washer Head Serrated Structural Screws

SPAX PowerLags 5/16 in. in. X 6-3/4 in. L T-40 Washer Head Serrated Structural Screws

Made in America

Support American manufacturers + independent hardware retailers in one purchase.

A 250-count bucket of self-tapping structural screws with the T-40 bit included, built for wood framing that has to hold.
Spax MPN 3581820801710 In Stock & Ready to Ship
$299.99
Free shipping on orders over $149
Ships within 24 hours · most orders arrive in about 2 business days
Ships free on orders over $149 $14.99 flat shipping until your order reaches $149.

About Product Overview

These SPAX PowerLags are built for structural wood-to-wood work, and the 5/16 x 6-3/4 in. size puts them squarely in framing and heavy timber territory. A 250-count bucket means you're not running short mid-job, and the washer head gives you a solid bearing surface without needing a separate washer.

The serrated thread design is self-tapping, so these bite into wood without requiring a pre-drilled pilot hole in most applications, saving setup time on multi-screw projects. Grade 5 carbon steel construction with a high corrosion-resistant finish means these hold up whether you're building outdoors or in. The T-40 drive style is included with the bucket, so you've got the right bit on hand from the first screw to the last.

Good fit for deck framing, post and beam connections, ledger boards, and other structural wood assemblies where you need a fastener that won't back out or shear under load.

  • Size: 5/16 in. x 6-3/4 in.
  • Drive style: T-40 (bit included)
  • Head type: Washer head
  • Material: Grade 5 carbon steel, black, high corrosion-resistant finish
  • Thread: Serrated, self-tapping (not self-drilling)
  • Packaging: 250-count bucket, rated for indoor and outdoor use

The Details Specifications

Brand Spax
Model / MPN 3581820801710
UPC 712216024427
Weight 21 lbs
Country of Origin USA
Safety Data Sheet (SDS) Manufacturer documentation · opens in new tab
Price check

Go ahead. Check.

You're going to price-check us against Amazon, Home Depot, and Lowe's. Everybody does. Good — open all three tabs. We'll wait. Then look hard at what you're actually being handed over there.

On Amazon, start with these four questions before you click buy.

01

Who's actually selling it

The brand name is on the listing. A different company is in the seller field. Those aren't the same thing, and the second one is who you're buying from.

02

Whether the warranty survives

Most manufacturers only honor a warranty when the unit came through an authorized dealer. We're authorized for Spax. A third-party marketplace seller usually isn't.

03

Where the box came from

Gray-market stock, returns repackaged as new, and outright fakes move through marketplaces constantly. It all looks identical in the photo. It stops looking identical when it fails.

04

Who you call when it breaks

Ours is a phone number with a person behind it who has held this product. M–F, 6 AM – 5 PM Pacific. (866) 469-8556

The big boxes don't care if your hardware store survives.

Amazon, Home Depot, and Lowe's are built to pull every hardware dollar out of your town. When the local shop can't keep the lights on, the counter where somebody actually knew which part you needed goes with it. We're built the other way: real brands so you're never stuck on a marketplace, and a straight answer to buy it down the street when that's the better call. Support independent hardware — it doesn't restock itself.

Why we tell you to shop local
Authorized dealer · Spax

Or skip the tabs entirely and buy it down the street. Find a store near you →

Shop Local · Support Independent

Every order helps keep your local hardware store on the corner.

Why we built NHG
You might find it for less locally. Independent retailers often offer competitive pricing — some products are even cheaper in-store than online.
Real expert advice — not search results. Independent hardware staff know their inventory and the local conditions you're working in.
Keep the neighborhood working. Every dollar spent at an independent retailer returns roughly 3x more to your local economy than at a national chain.

Ask our counter. Or theirs.

Most hardware stores can do more than you think. If we can't help you, the folks down the street probably can — just ask at the counter.

What we offer
Shop Your Local Store Ship to your hometown store
Pro & Gov Accounts Net terms · tax-exempt
Ships Nationwide Direct to your door
Shop Local First Real hardware stores
$0.68 of every dollar spent at a local independent business stays in the community. At a national chain, it's about fifteen cents. Civic Economics, multi-city retail studies
100% Authorized & Genuine — Our Guarantee →
Their Counter
Try local first · we'll wait

The stores we send you to are local and independently run — often for generations, the kind of place where someone behind the counter knows the regulars. We don't own them. We just think they deserve the foot traffic. They can put most of what we sell on their next truck. Ask there before you check out here.

Find a local store →
Mon–Fri 6–5 PST
Independent hardware retailer? Join the network → Make hardware content? Earn 6% as a creator →
About our directory. National Hardware Group is an independent retailer and directory. The local stores we list and link to are separately owned and operated — we have no ownership stake in any of them, and most pay us nothing to be included. That includes plenty of stores flying a familiar banner that people don't realize are locally owned and run, not operated by a corporation. Store owners can choose to upgrade their listing for an enhanced presence or pickup features, but the base directory is free, and inclusion is never a paid endorsement.

Compare products

{"one"=>"Select 2 or 3 items to compare", "other"=>"{{ count }} of 3 items selected"}

Select first item to compare

Select second item to compare

Select third item to compare

Compare