FASTEN UP —

EVERYTHING YOU SHOULD KNOW ABOUT FASTENERS

UNDERSTANDING WHAT FASTENER TO USE WHERE CAN MEAN THE DIFFERENCE BETWEEN A RELIABLE BUILD AND ONE THAT’S ALWAYS UP ON JACK STANDS. WE TALK WITH AUTOMOTIVE FASTENER EXPERT PHIL DEAN OF KEY WEST BOLT AND SUPPLY TO GET THE LOW-DOWN ON WHAT OPTIONS ARE AVAILABLE FOR AUTOMOTIVE APPLICATIONS. NORD-LOCKS, CONE LOCKS, K-NUTS, AND BLACK-STEEL CAP SCREWS — BUILD YOUR CAR ONCE AND BUILD IT RIGHT COPPER-COATED LOCKING NUTS

Perfect for applications such as manifolds, these are top locking with an ovaled thread. Copper-coated steel ensures that they do not seize, which is a common occurrence with uncoated steel nuts. These nuts are available in sizes M6–M10 and are often used in conjunction with a grade-nine washer on a screw-in stud for exhaust manifolds.

SHANKED BOLTS

These are used in high-stress applications such as suspension. The strength of shanked bolts lies in the shanked unthreaded part of the bolt, and your local cert man will require at least 80 per cent shank through the bush or joint. It’s worth noting that at least three full threads will need to show past the nut.

BRASS MANIFOLD NUTS

Although these are not locking nuts, the brass is able to shrink and expand with heat cycles and does a great job of holding tension. These were popular in early cars, and your grandad probably used them in his flathead builds. However, they are not common in modern applications.

SERRATED FLANGE NUTS

Flanged steel nuts with a serrated flange surface, these are great in locations such as non-turbo exhaust manifolds and a great replacement for a spring washer–flat washer combo when mild heat will be experienced. They are popular in carb-tomanifold studs or anywhere that there is not enough thread to have a locking washer. The serration bites into the surface to hold tension. These are a multi-use nut.

SPRING WASHERS

The most common and cost-effective anti-vibration washer, the classic spring washer should be used anywhere that parts are continuously serviced, as it can be used over and over. A spring washer should never be used where heat is present, as it will lose its tension. A spring washer is commonly used with a flat washer as a combo but can also be used alone. You can also get reduced-circumference versions that are perfect for use with cap screws.

K-NUTS

When it comes to extreme heat locations such as downpipe V-bands, wastegates, and two-piece brake rotors, it's hard to go past K-nuts — flanged and ovaled locking nuts but with reduced hex size, which makes them extremely lightweight. High-temp versions are cadmium plated, although non-high-temp black-steel variants are also available.