Concrete Screws, Flat Head, 410 Stainless Steel, 1/4” Diameter Extra Long – Available Lengths

Extra-long 410 stainless steel flat head concrete screws in 5" and 6" lengths, for fastening through thick ledgers, furring, stacked shims and sill plates into concrete, brick, grout-filled CMU and hollow block. DeWalt Crete-Flex® #14 anchors install with a 1/4" carbide bit and a #3 Phillips driver. For standard lengths see the 1/4" flat head screws, or all 410 stainless flat head concrete screws.

Concrete Screws, Flat Head, 410 Stainless Steel, 1/4" x 5" DeWalt Crete-Flex® MPN DFM4EMF830S

Extra-long 410 stainless steel flat head concrete screw, 1/4" x 5", for exterior and high-moisture fastening into concrete, brick, grout-filled CMU and hollow block. Cuts its own threads — no shield, plug or expansion sleeve. Florida Product Approval FL29068. DeWalt Crete-Flex® MPN DFM4EMF830S.

$2.19

In Stock.

Concrete Screws, Flat Head, 410 Stainless Steel, 1/4" x 6" DeWalt Crete-Flex® MPN DFM4EMF850S

Extra-long 410 stainless steel flat head concrete screw, 1/4" x 6", for exterior and high-moisture fastening into concrete, brick, grout-filled CMU and hollow block. Cuts its own threads — no shield, plug or expansion sleeve. Florida Product Approval FL29068. DeWalt Crete-Flex® MPN DFM4EMF850S.

$2.85

In Stock.

Choosing an Extra-Long Concrete Screw

Standard 1 1/4" to 4" concrete screws cover most direct-to-slab fastening. The 5" and 6" Crete-Flex® anchors on this page exist for the jobs where the fixture stack eats the embedment: doubled ledgers, thick furring over uneven block, stacked shim packs, and pressure-treated plates over rigid insulation. Subtract your full fixture thickness from the screw length to confirm you still land at least 1" of thread in the base material before you order.

Key Features

410 stainless steel with Stalgard® coating for corrosion resistance in exterior and high-moisture work
#14 diameter — .268" outside diameter, .201" root diameter
Phillips flat head, #3 drive — countersinks flush into wood and composite fixtures
Installs with a 1/4" carbide-tipped hammer drill bit
40° V-notched thread for efficient tapping and reduced installation torque
Florida Product Approval FL29068
Base materials: concrete, brick, grout-filled CMU and hollow block

Installation

Drill with a 1/4" carbide bit to at least 1/2" deeper than your intended embedment.
Blow or vacuum the hole clean — dust left in the hole is the most common cause of low pull-out values.
Position the fixture and drive the screw with a #3 Phillips bit at low to moderate speed.
Stop as the head seats flush. Over-driving strips the tapped threads and loses the anchor.

Frequently Asked Questions

How deep does a 6" concrete screw need to go into the concrete?

Embedment, not overall length, carries the load. Plan on a minimum of 1" of thread in the base material and confirm against the DEWALT load tables for your embedment depth and concrete strength.

What drill bit do these use?

A 1/4" carbide-tipped bit. These are #14 screws — .268" at the thread crest, .201" at the root — so a 1/4" bit falls between the two, which is what lets the screw tap its own threads. Note this differs from the 3/16" bit used by 1/4" Simpson Titen® screws; the two are not interchangeable.

Is 410 stainless suitable for saltwater exposure?

410 is a hardenable martensitic stainless that gives good corrosion resistance for exterior and high-moisture work, and the Stalgard® coating adds to it. For direct saltwater immersion or splash-zone work, step up to a 316 stainless concrete screw.

Can these be removed and reused?

They can be backed out, but the tapped threads in the concrete are compromised. Reinstall in a fresh hole rather than reusing the same one.