Fasteners Buying Guide

How to Choose the Right Fasteners

Quick answer: Match fastener material to the environment (corrosion exposure), thread type to the substrate (wood, machine, sheet metal, or masonry), grade to the actual load, and drive/head type to whatever tool you'll run in volume — mixing these up is more common than buying the wrong size.

Fasteners look like the simplest purchase in the catalog until the wrong one fails — corrodes, strips, or shears under a load it wasn't rated for. Here's how to spec the fastening lines we stock correctly.

Match material to the environment before anything else

Zinc-plated steel is the standard for dry, indoor, general-purpose use and costs the least, but it corrodes in exterior, high-moisture, or treated-lumber applications. Stainless steel resists corrosion for outdoor and wet-environment use, and it's required (not optional) for fastening into modern ACQ-treated lumber, which corrodes standard zinc-plated fasteners much faster than untreated wood. Coated fasteners (like exterior-rated deck screw coatings) split the difference — cheaper than stainless, but rated for treated lumber and outdoor exposure. Picking based on price alone in an exterior or treated-wood application is the single most common fastener mistake we see.

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Match thread type to the substrate

Wood screws, machine screws/bolts, and self-tapping sheet metal screws aren't interchangeable even when the diameter matches — wood screw threads are coarse and spaced for wood fiber grip, machine screws thread into a pre-tapped hole or nut, and self-tapping screws cut their own thread into thin metal as they're driven. Using a wood screw in metal (or a self-tapper in wood) either won't grip properly or will strip the material. Our screws and fasteners line covers all three; match the thread type to the material before comparing length or head style.

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Grade and strength: don't undersize a load-bearing connection

Bolts and structural fasteners carry grade markings (visible on the bolt head) that indicate tensile strength — a higher grade bolt in the same diameter can carry significantly more load before failure. For anything load-bearing or safety-relevant (structural connections, equipment mounting, overhead securing), spec by grade and rated load, not just by diameter matching an existing hole.

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Drive and head type: match the tool you'll actually run

Phillips drive is the most common but strips out easily under power-driver torque; square and star (Torx) drives resist cam-out and hold up much better for repetitive powered driving. If a job involves driving more than a handful of fasteners with an impact driver or drill, a strip-resistant drive type saves real time over Phillips, even at a slightly higher per-unit cost. Head style (flat/countersunk, pan, hex) should be chosen for the finished look and clearance needed, not just whatever's in stock.

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Anchors and mechanical fastening for masonry and drywall

Our fastening line covers anchors and mechanical fasteners for base materials that a standard wood or machine screw can't grip directly — concrete, block, brick, and hollow drywall each need an anchor type matched to both the base material and the load. A drywall anchor rated for light picture-hanging loads has no business holding a shelf bracket; matching anchor load rating to the actual hung weight (with a safety margin) matters as much as matching it to the wall material.

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Standardize sizes and buy in bulk for anything used regularly

For fasteners used repeatedly on the same type of job, standardizing on one or two sizes/grades and buying in bulk quantities cuts both cost per unit and the time spent hunting for the right fastener mid-job. Save assortment kits for occasional or variable work where you don't yet know what sizes you'll need most.

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Quick buying checklist

  • Match fastener material to the environment — stainless or coated for outdoor/treated lumber, zinc-plated for dry indoor use
  • Match thread type (wood, machine, self-tapping) to the actual substrate, not just the diameter
  • Spec load-bearing connections by grade and rated strength, not diameter alone
  • Choose strip-resistant drive types (square, Torx) for any job driving fasteners in volume with a power tool
  • Match anchor type and load rating to both the base material and the actual hung weight
  • Standardize and buy in bulk for regularly used sizes; use assortment kits only for variable work

Matching a thread size? See the threaded insert size chart: inch and metric thread sizes with the inserts and tee nuts we stock.