Specular Grinders: XRF-Verified 304 Stainless Steel
Saying "304 stainless steel" is easy. SHOWING it is different.
Anyone can put "food-grade stainless steel" on a product description, but it doesn't mean that their product is actually made from 304 stainless. We sent our flagship grinder, the Specular OG1, to an independent lab that tests metal parts for aerospace applications, where it was put under a Thermo Fisher Scientific Niton XL3 handheld X-ray fluorescence (XRF) analyzer, on camera, and we've published the reports here. The analyzer identified the material of the OG1 grinder as SS-304, a chromium-nickel stainless steel grade valued for its corrosion resistance and durability. Here are the details.
The OG1 under a handheld XRF analyzer. Handheld XRF (X-ray fluorescence) is used for alloy verification in aerospace, manufacturing, and industrial quality control. Full test, no cuts in the video documentation.
What is 304 stainless steel?
We should first explain the basic distinction between 304 stainless steel and free-machining 303 stainless steel, so that readers can understand why testing our metals is important in the first place.
303 is a sulfur-modified, free-machining grade of stainless steel. The main difference with 303 is that sulfur is added to the alloy specifically to make it faster and cheaper to machine. However, that sulfur also reduces the metal's corrosion resistance and weldability, and it creates sulfide inclusions that make the surface more susceptible to localized corrosion over time. On a grinder this can show up as small dark "pits" on the surface of the metal that can spread or rust over time.
304 stainless steel, or SS-304, does not rely on that sulfur addition, so it holds up much better against corrosion. This means that 304 stainless steel costs more to machine and takes longer, but it performs much better in the long term. You'll see this most commonly in the superior surface quality of the metal over time. This is why SS-304 is widely used in demanding industrial and precision applications, and why we choose to make our stainless steel grinders from SS-304.
| Element | XRF measurements | What it means |
|---|---|---|
| Fe (Iron) | 71.2–71.6% | The primary base metal in stainless steel. |
| Cr (Chromium) | 17.18–17.25% | A key alloying element responsible for stainless steel's corrosion resistance. |
| Ni (Nickel) | 7.99–8.47% | Our readings show substantially lower manganese and higher nickel than the composition typically associated with Type 201. |
| Mn (Manganese) | 1.80–1.96% | Low manganese. |
| S (Sulfur) | 0.111% | 0.111% reported on the mid-piece in one small-spot reading, which carries larger measurement uncertainty; the top and bottom readings did not report sulfur. The instrument still identified that component as SS-304. Full bulk chemistry, including sulfur and carbon, would require an appropriate laboratory chemistry method. |
| Pb, Cd, Sb | Below detection limits | Lead, cadmium, and antimony were below the instrument's reported detection limits in all three readings. These elements were reported by the analyzer in General Metals mode. |
What XRF testing is
We sent the three stainless steel body components of a finished production OG1, the same grinder we ship to customers, to be tested via XRF. XRF stands for X-ray fluorescence. The analyzer uses XRF to measure detectable elements in the metal and compares the resulting composition against an alloy library, providing rapid, nondestructive material identification.
Handheld XRF is used for alloy verification in aerospace, manufacturing, and industrial quality control. Our readings were collected using a Thermo Fisher Scientific Niton XL3 handheld XRF analyzer.
Why we tested our metal
We got burned before we built the OG1. You buy something marketed as "premium" stainless, and six months later it looks dull, feels tacky, or starts to rust. And the "premium" material claim was never checked or proven by anyone.
Even though we source our materials from trusted sources, we wanted to provide proof to our customers that our marketing claims are legit. So we sent our finished product to an independent lab that tests metal parts for aerospace applications, and had them test the components individually (lid, grinding body, collection chamber) under a Thermo Fisher Scientific Niton XL3 handheld XRF analyzer. The analyzer identified all three as SS-304.
The certificate
This is the actual Certificate of Verification generated by the analyzer. The short version: the analyzer identified SS-304 on all three tested components. Lead, cadmium, and antimony were below the instrument's reported detection limits in every reading. Sulfur was reported only in the mid-piece small-spot reading, at 0.111%; the top and bottom readings did not report sulfur, phosphorus, silicon, or magnesium. Handheld XRF was not used to certify bulk sulfur content.
XRF Certificate of Verification, page 1 of 3 · Thermo Fisher Scientific Niton XL3
Three components. Consistent results.
Three handheld XRF readings, one per component, taken separately. The iron, chromium, nickel, and manganese readings agree within about half a percentage point across all three.
Top and bottom pieces
SS-304 identified · match value 0.00 on each
Middle piece (3 mm small spot)
SS-304 identified · match value 1.36 · wider measurement uncertainty
We also used a second, totally different analytical method, SEM-EDS electron microscopy, which separately examined the surfaces and elements. We've documented this in Part 2 of our report for those who want to get really nerdy. See Part 2: Under the Microscope →
How to read these numbers, straight up
The measured chromium and nickel values should be interpreted as handheld XRF measurements from a finished surface, not as a mill chemistry certification. Published Type 304 (UNS S30400) chemistry commonly lists chromium at 18.0 to 20.0% and nickel at 8.0 to 10.5%. Handheld XRF on a finished, unprepared surface can read differently from mill certificate values, and the instrument's grade match is made against its own alloy library, not against a mill spec. That is why we present this as positive material identification: the analyzer identified all three tested components as SS-304. A properly prepared bulk chemistry analysis, such as spark OES, would be needed to determine compliance with a specific bulk chemistry specification, and that is the next test on our list. We publish the complete test documentation so you can read it yourself.
SS-304. Identified by XRF, not just claimed.
The Specular OG1 grinder is precision-machined from metal tested and identified as SS-304. We've made the test reports public.
See the OG1 Part 2: Under the Microscope