Fastener Materials and Finishes
It shouldn’t surprise you to hear that there is no single best material for making screws, just as there is no single best fishing lure or garden fertilizer. It all depends on the application, of course. Hardened steel screws are the work horse for many situations, but are entirely unsuitable for most exterior applications unless properly coated or plated. The following short course should help you determine the best fastener for your application.
Un-plated Hardened Steel Screws
Un-plated Hardened Steel screws are the most popular, and are primarily used where they will not be visible or exposed to corrosive conditions. Their color variation from almost pure black through a bronze to silvery grey does not affect quality – it is simply a result of process-variable interactions as simple as the screw’s location on the heat treat furnace conveyor belt. All McFeely’s un-plated screws receive a Dry-Lube finish which reduces driving torque requirements, but provides virtually no corrosion resistance. Hardened steel screws are the base stock for all our plated screws.
Stainless Steel Screws
Stainless Steel provides the ultimate corrosion resistance for most woodworking projects. It is softer than our hardened steel screws because stainless steel is not generally heat-treatable – the wire must be soft enough to be formed, yet hard enough to provide the desired strength. We carry stainless steel in a variety of grades. Note: Not all grades are designed to be completely “stainless”!
Aluminum is surprisingly strong because it work-hardens as it is formed into screws. Ours are made of 2024-T4, an aircraft grade suitable for screw manufacturing. These screws are just the thing for assembling aluminum doors, windows, or gutters because they eliminate the corrosion problems associated with the more common use of zinc-plated fasteners.
Solid Brass Screws
Solid Brass screws are also very soft, and virtually demand a carefully sized pilot hole to eliminate installation breakage. (Pre-threading the hole with a steel screw helps minimize this problem.) A Square Recess really makes a difference with these screws. The softness of the brass greatly increases cam-out problems with most other driver types, a situation neatly overcome by the Square Recess.
Fresh Silicon Bronze Screws
“Oxidized” Silicon Bronze screws are primarily used for marine boatbuilding, although many people have used them to build decks made of Western Red Cedar or Redwood because the screws will eventually blend into the color of the wood. As pictured, screws right off the production line are generally the color of a fresh penny – after they have been around awhile they oxidize and darken as shown in the “Oxidized” Silicon Bronze picture.
Selecting the proper finish for your screws is a new experience for many woodworkers. After all, most of the time you don’t have a choice! If you don’t like bright zinc, or it isn’t suitable, it’s just tough luck. We offer a wide variety of finishes and materials – not to add to the confusion – but to make sure you can have the most appropriate fastener for your task!
Black Oxide Screws
Black Oxide is a very popular plating because it has a black color (perfect for exposed screw heads on “High-Tech” styled products), and it provides just enough corrosion protection to prevent rusting of imported fasteners during their 3-week boat ride. Plated with Black Oxide for purely decorative reasons.
Statuary Bronze Screws
Statuary Bronze is a decorative finish designed to match the antique appearance of old cabinet hardware. Primarily dark bronze, with highlights of copper. Highlights increase on screws exposed to wear or abrasion.
Yellow Zinc Screws
Yellow Zinc resembles Bright Brass plating, but appears more iridescent. It offers a modest amount of corrosion resistance (approx. 100 hours’ salt spray to 10% red rust).
Bright Brass Screws
Bright Brass is a purely decorative finish designed to generally match the color of most cabinet hardware. It provides little corrosion resistance, although in highly acidic woods like red oak, it can prevent the dark blue stains that sometimes form around an un-plated screw.
Clear Zinc Screws
Clear Zinc is another largely decorative plating, although it does offer a salt spray rating to 10% red rust of about 50 hours. A good choice for interior applications when working with acidic woods like red/white oak, or when the screw will be countersunk and plugged. It is a poor choice for most exterior applications.
NoCoRode Plus Screws
NoCoRode Plus is steel screw with one of the most corrosion-resistant platings we offer. In manufacturer conducted salt-spray testing it has exceeded 1,800 hours, making it almost 20 times more corrosion-resistant than standard Yellow Zinc plating. It works well with most outdoor woods, including ACQ pressure-treated, but use caution with Redwood, Western Red Cedar or similarly acidic woods – these tend to stain, sometimes even with stainless! And unlike the plating on hot-dipped galvanized screws, NoCoRode Plus doesn’t chip and break. This process can have a minor amount of recess fill so we recommend using our NoCoRode Undersized driver bits. Best of all, the plating is tan colored, so that it “blends” with many pressure-treated materials.
Can’t find the answers you’re looking for? Call 800-443-7937 and ask for our Product Support Department or send us an email at firstname.lastname@example.org