Interesting Facts

Fasteners: Common Myths, Misconceptions, and Errors.

The heads are breaking: We hate this phone call more than any other call. In every single case over the past twenty five years, it’s never been the screw. Ever, Not once. Screws have recommended installation torques. Each screw is different, but it’s usually around 1,000-2,000 RPM. When you go faster than that , the head will sometimes break. That is not a fastener failure that is a user installation failure. "But I’ve always done it that way" is a common response. For many years asbestos was used in ceilings because they’ve "always done it that way" that doesn’t mean it was a good idea.

Impact Driver vs Screwgun:

Recommended drill speed into Steel Purlin is 2400 ' 2500 rpm max
Recommended drill speed into Timber is 1500rpm max
By comparison a Screwgun is max 2400 rpm and an Impact Drivers is 3200 rpm!!!!!!
Impact drivers are not designed for self drilling screws, particularly into steel and can result in the following problems;
Tips of self drilling screws are damaged resulting in burn-out or will not drill properly.
Damaged or broken threads going into steel purlins, resulting in severely reduced holding power.
Magnetic sockets will damage and remove paint from the head of the screw.
Impact Drivers can crack or split the protective galvanised coating, resulting in premature corrosion of the screw.
Fasteners can be overdriven particularly on pan fixed products, creating dishing around the fastener. Impact Drivers do not have a clutch or depth locator to reduce overdriving problems.
Heads can break on pan fixed screws.

Self-Drilling vs Self-Tapping: These terms are commonly confused. A self-drilling screw has a drill bit style point. They are often called Tek®screws, which is a brand name and not be used to refer to generic screws. A self-tapping screw has a sharp point normally and is a type "A" or "AB" though there are other variations, such as "B" point which are blunt.

Coated vs Uncoated Screws: A lot of people say "oh the grey screws don’t work. Generally the colour of a screw cannot affect its performance in a negative way. Different coloured plating’s or coatings do not cause fastener failure.

Stainless Steel Doesn’t Rust: That’s a commonly believed statement but it’s wrong. Almost all alloys can eventually rust because they contain traces of carbon. Any metal that has traces of carbon can rust. 302,304, and 316 stainless do rust but it takes a long time. 410 stainless rusts as quickly as steel, but since it’s generally surface rust, the integrity of the screw is not usually compromised.

While 410 stainless is stronger than 300 series, it will develop rust. A common method in retarding the rust is the use of plating’s or coatings. Coatings and plating’s also help the problem of galvanic reactions between dissimilar metals such as aluminium and stainless steel.

Stainless Steel is not magnetic: In stainless fasteners, 300 series stainless is non-magnetic in its Raw Condition. Cold working it (making the parts) can sometimes cause traces of magnetism in 300 series. An increase in magnetism is caused by the heat and friction of cold forming and Does Not Reduce corrosion resistance. 400 series is magnetic because of it high carbon content.

316 stainless is stronger than 304 stainless: That just isn’t true. 316 stainless may be slightly stronger in many applications using larger diameter bolts, but 316 is not stronger in any statically significant way on most standard size screws. 316 stainless does in most applications , exhibit much better anti-corrosive properties but that’s not a strength issue.

Strength of 410 Series Fasteners: As these are heat treated, tensile, yield, strength and drill speed are the same standard as a carbon steel fastener.

Selecting the correct Stainless Steel Self-Drilling Screw: When penetrating through steel studs or other light gauge steel 410 (heat treated) or a Stainless Steel Bi-Metal screw is necessary.

When penetrating into Aluminium 300 series stainless may be used.