Not all stainless steel are created equal. We have gone on ahead and produced our own spring bars with superior steel properties. Hopefully, this article will help justify the extra steps we have taken for offering something so small and simple.
Three common stainless steel grades used in the watch industry are 304, 316L, and 904L - the latter mostly used exclusively by Rolex. What makes these steel different? Why would someone use one over another? We are here to answer those questions.
304, 316L, and 904L are austenitic steel. The steels contain 16 to 26 percent chromium and up to 35 percent nickel, making it having a high corrosion resistance property. They are not hardened by heat treatment and are nonmagnetic. For the purpose of what we offer, we will only compare 304 and 316L stainless steels.
Have you ever noticed the '18/10' stamp behind your kitchen utensils? 304 grade is the standard food grade stainless steel, which contains 18 percent chromium and 10 percent nickel; it is the most widely used stainless steel and available in a wide range of products, forms and finishes. It has excellent forming and welding characteristics.
Corrosion resistance for 304 is generally very good in a various atmospheric environments and many corrosive medias. However, it is subject to pitting and crevice corrosion in warm chloride environments; stress corrosion cracking may occur when reaching above 60°C.
The typical applications for 304 include but are not limited to food processing equipment; kitchen benches, sinks, and appliances; architectural paneling, railings and trim; chemical containers; threaded fasteners; and springs to name a few.
Our 1.8mm Fat 304 Stainless Steel Spring Bars are a good choice for everyday use. They are not too thick and can slide though most of the leather and nylon straps while still having a good resilient property to stress and water.
Grade 316L, the low carbon version of 316, is the standard molybdenum-bearing austenitic grade. It ranks as the second most important stainless steel after 304. The molybdenum properties give 316L better overall corrosion resistance compared to 304, particularly higher resistance to pitting and crevice corrosion in chloride environments. It is readily brake or roll formed, welded, soldered and cut by both thermal and mechanical methods. The austenitic structure also gives excellent toughness. 316L is usually regarded as the standard “surgical grade” or "marine grade" stainless steel.
The typical applications for 316L include but are not limited to laboratory equipment; surgical equipment; boat fittings; chemical containers; screens for mining, quarrying & water filtration; watches; and Strap Mill Canada's Extra Fat Spring Bars.
The 316L stainless steel is more resilient in a marine environment compared to 304 stainless steel. If you expose your watch in swimming pools or ocean often, the 316L SS would be the better choice - they have a better steel property and have a thicker diameter (2.0mm) to ensure it can withstand higher physical stress. With that said, it is always a good practice to inspect and replace your spring bars often to ensure they are in optimal working condition.
What are our bent spring bars for? you may ask. They are mainly to create extra clearance between your watch case and spring bar so you can slide straps through without rubbing the strap. More details in our second half of How to Change Into a Nato Strap article.
Hopefully, this answers some of the questions you may have regarding our different spring bars offering.