Fastenings Catalogue 2020/21 - Catalog - Page 10
8
SCREWS
Screw Drive Types
Torx is a tough drive type, the star shape strongly grips the
driver bit to help prevent stripped heads. Torx comes in
different sizes depending on the size of the screw head, T15
for the smallest to T40 for big screws. Torx is a decorative
finish and is used mainly in decking and landscape screws.
Best
Internal Hex is a powerful drive type used in big diameter
batten and landscape screws. The hex shape is heavy-duty
and can take a battering from impact drivers.
Better
Square is the foremost drive type sold in NZ, square
significantly reduces rounding- out of the drive by the driver bit
compared with Pozi & Phillips screws. 3 square sizes (#1,
#2 & #3), #2 square being the main volume size.
Pozi & Phillips head screws can be easily rounded out with
worn driver bits or using too much torque on the screwdriver,
making the square drive screw a stronger choice.
Good
Corrosion Resistance
Best
Stainless Steel grade T316 – for the highest corrosion resistance and is suitable
for outdoor use in coastal areas and extreme conditions.
Stainless Steel grade T304 – for very good corrosion resistance and is suitable
for most outdoor applications exposed to the elements, use T316 grade for coastal.
B8 – is a hardwearing corrosion protection that is better performing than standard
galvanised fastenings, for outdoor landscape projects using heavy duty timber
screws and used in roofing screws.
Class 4 Galvanised – is a galvanised coating over the metal fastener and is
a minimum corrosion protection for outdoor applications.
Good
Zinc – offers the minimum amount of corrosion protection and is intended for
interior applications.
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