Stainless Steel Self Drilling (Tek), Screws

[Supreme Screws]

Are They Hard Enough?
Stainless Steel Self-Drilling Screws (Tek) - What are they?
A screw that can self-drill into steel is the 'Self Drilling Screw for Metal'. Many types of materials are available, each with its strengths and weaknesses.

What is the importance of grades?
It is crucial to choose a suitable material for your application. Some Stainless Steel Screws grades are resistant to corrosion (304 and 316), but they are soft and won't self-drill as much as thin aluminium. Some steps, such as 410, are heat-treated and have excellent hardness. However, if you're near saltwater or any coastal environment, you'll see some tea staining very quickly!

Marutex and Hardtec are two of the best Stainless grades, but they only come in Hex Washer Face Head styles. Choosing the right material type and grade for your application is crucial.

Stainless Steel Self Drilling Screws (Tek) - So what's the best?
The Stainless Steel Self Drilling Screws come in four primary materials within the Stainless Range.

Bi-Metal Self-Drilling Screws – These are not entirely Stainless. The Bi-Metal screw usually has a 304 Stainless Steel head and a Carbon Steel tip. They are tough and can be used for drilling due to their Carbon Steel tip. However, they are not 100% Stainless Steel. They usually have a 500hrs salt spray protective Ruspert coating to increase their corrosion resistance.

410 Stainless Self-Drilling Screws – These are 100% Stainless. 410 is a Martensitic Stainless, which can be hardened with heat treatment (which Austenitic types 304 or 316 cannot). It is, therefore, beneficial for drilling. However, 410 has a lower corrosion resistance than grade 304. Tea-staining or high-corrosive environments should be avoided.

304 and 316 Stainless self-drilling screws - The 300 series of Stainless steel have an Austenitic crystal arrangement. Heat treatment is not possible for the 410 grade. The 300 series screws are resistant to corrosion but are only suitable for drilling through thin aluminium because of their softness—Europeanly, also known as A2 (304) or A4 (316).

Hardt/Martuex Stainless – Both 'Hardtec' and 'Marutex are proprietary grades of Stainless Steel made for Stainless Self Drilling Screws. These grades are heat treated to harden them, which gives them excellent drilling performance in metals such as grade 410. However, unlike grade 410, they have Molybdenum and corrosion resistance properties comparable to the 300 series Stainless grades. Salt spray tests prove they have corrosion resistance similar to or better than 304 grade and not too far behind 316 Stainless steel. They make a great screw!