Made for all exterior applications except continuous exposure to seawater, these screws are the best quality you will find anywhere and are suitable for architectural applications.
The screws are produced from 18-8 grade Stainless Steel as it offers the best blend of strength and corrosion resistance without brittleness.
Stainless steel screws are moderately strong in tension and shear but are not as strong as the hardened steel screws so you need to watch the torque and pre drill in most timbers.
Origin of the Robertson square drive screws
The "Robertson" screws were invented in Canada by Peter Robertson in 1908. Due to patent restrictions they stayed in Canada for many years and became the standard screw in that country. They are now spreading rapidly through the US and other countries. It is a far superior system and we are sure you will agree “once you use them you don't want to use anything else”.
Not only is the drive system better than the conventional drives, the actual quality of the screws is superb. The screws are extremely strong and the square drive means the driver doesn't jump out and the screw does not break under heavy load.