Mitutoyo Surftest SJ-220 Features: 0.75 mN vs 4 mN — Which One Do You Need?

Mitutoyo is a Japanese precision measuring instrument manufacturer founded in Kawasaki in 1934, starting with a single product: a micrometer. Today it's widely regarded as the world's largest metrology company, offering thousands of measuring products — from hand tools like calipers and micrometers to coordinate measuring machines, vision systems, and surface roughness testers — used across manufacturing industries worldwide.

Note for SJ-210 Users: The legendary predecessor, the Mitutoyo Surftest SJ-220's older counterpart (SJ-210), has been officially discontinued in Japan. If you are currently using an SJ-210 or trying to source replacement parts for it, the SJ-220 is its direct and upgraded successor.

If you're searching for a Mitutoyo Surftest SJ-220, this guide covers what it is and walks through its two measuring-force versions — 0.75 mN and 4 mN — so you can pick the right one for your material. If you're working with soft, delicate, or easily scratched surfaces (resin parts, thin coatings, finely polished metal), the 0.75 mN version is the one to look for.

What Is the Mitutoyo Surftest SJ-220?

What it is: Mitutoyo's portable surface roughness tester, built for on-site inspection rather than lab-only use. It's compact, battery-powered (rated for roughly 1,000 measurements per charge), and designed to work like a handheld tool.

Why it's recommended: It features a 2.8" touchscreen display, support for 25 languages, and physical buttons (usable even with gloves on) that make it practical on a shop floor without bringing the workpiece to a bench-mounted machine.

Standard Probe vs. 0.75 mN Low-Force Probe

What it is: The SJ-220 is available in exactly two measuring-force configurations (0.75 mN version [178-741-11] and 4 mN version [178-742-11]). The lower-force version uses a 2 µm tip radius with a 0.75 mN force, while the 4 mN version uses a 5 µm tip radius.

Why it's recommended: The lower measuring force reduces the risk of marking or deforming soft or delicate surfaces (such as plastic/resin components, soft coatings, or finely lapped metal surfaces). If your parts are hard metal and surface durability isn't a concern, the 4 mN probe is more affordable.

Where to buy: View 0.75 mN Version on eBay | View 4 mN Version on eBay

Key Features & Standards Support

What it is: A versatile tester supporting intuitive touch operation, USB and RS-232C interfaces, optional wireless data transmission (U-WAVE-TIB), and compliance with global standards including JIS, ISO 21920:2021, ASME, and VDA.

Why it's recommended: It allows seamless integration into multi-standard manufacturing environments and supports dedicated apps (SJ-App / SJ-Communication-Tool) for creating inspection reports and managing data effortlessly.

Drive Unit Options

What it is: Available with a standard drive unit, retractable drive unit, or transverse tracing drive unit depending on your measurement scenario.

Why it's recommended: Different setups handle specific challenges — from standard on-site checks to lifting the detector clear for automated setups or measuring narrow features like crankshafts and wire-EDM surfaces.

Conclusion

Whether you need to measure delicate resin parts with the 0.75 mN probe or standard machined components with the 4 mN model, the Surftest SJ-220 brings laboratory-grade precision directly to the shop floor.