A 2026 Biuged specification sheet for the BGD 930 / BGD 931 lists Ra 0.005–16 μm, Rq 0.005–16 μm, Rz 0.020–160 μm, and Rt 0.020–160 μm, conforming to ISO 4287, DIN 4768, JIS B, and ANSI 146.1 [S10]. That range envelope is the practical lower bound for any general-purpose shop-floor selection on aluminum, steel, and hardened sealing faces.
Buyers in mid-2026 are spoilt for portable form factors: PCE-RT 10 packs Ra/Rz measurement into a wireless pocket unit with LCD readout [S1]; the PCE-RT 1200 adds a piezo probe for Ra, Rz, Rt, and Rq [S2]; Mahr's MarSurf M 310 adds Bluetooth and a built-in printer for paper-trail QA [S3]; Taylor Hobson's Surtronic S100 and DUO cover shop-floor and separable-handle inspection [S6]. Decision is no longer about whether a portable exists — it is about which parameter set, trace length, and probe geometry matches the part.
Parameter Set: Ra, Rz, Rt, Rq — and When Each One Matters
The PCE-RT 1200 computes Ra, Rz, Rt, and Rq from a piezo-electric stylus trace, giving it the same parameter coverage as a bench unit in a handheld shell [S2]. The BGD 930 line covers the same four parameters and is the configuration most often quoted for inbound inspection of turned, milled, and ground components [S10].
Ra is the arithmetic mean roughness used as a default on machined shafts and turned OD/ID surfaces. Rz (mean peak-to-valley over the sampling length) is the parameter sealing engineers ask for on flange faces and O-ring grooves, because it controls the leak path. Rq (RMS) and Rt (max peak-to-valley) come into play on honed bores and super-finished rollers. If a tester cannot resolve all four, force the buyer to specify which surface the part will live in — not which number is easiest to read.
Probe, Stylus Tip Radius, and Traverse Length
Stylus geometry is the single largest hidden variable on a surface roughness tester datasheet. PCE's piezo probe variants (RT 1200) are designed for traceable lab-grade work; the compact RT 10 prioritizes wireless shop-floor screening over a long trace [S1][S2]. Mahr's MarSurf M 310 portable skid-style probe is a known shop-floor configuration with Bluetooth output [S3].
Rule of thumb from seasoned metrology hands: 2 μm tip radius for soft non-ferrous, 5 μm tip radius for general steel, and skid-style probes only when the sample is flat and horizontal. Traverse length must be at least five times the sampling length (per ISO 4287 evaluation length conventions) — anything shorter is a screening value, not a reportable value. Confocal and area-averaging methods such as the REA approach described in Scientific Reports expand Sa measurement to a steady-state field rather than a single 2D trace, and that matters for optics-grade quartz and glass where local variation is high [S7].
Standards Conformance: ISO 4287, DIN 4768, JIS B, ANSI/ASME B46.1
The Biuged BGD 930 / BGD 931 datasheet explicitly lists ISO 4287, DIN 4768, JIS B, and ANSI 146.1 (B46.1 family) as covered standards, with metrology-grade units in μm and μinch [S10]. That declaration is what turns a handheld number into a value you can stamp on a PPAP or an inspection certificate.
ISO 4287 governs the 2D parameter definitions (Ra, Rz, Rq, Rt); ASME B46.1 (and its ANSI predecessor) governs U.S. surface texture specification language. If a vendor cannot name which ISO/ASME clause its Ra value is traced to, walk away. For 3D areal parameters (Sa, Sz, Sq) the 2D datasheet does not apply — the buyer needs to step up to an area-topography instrument.
Form Factor vs Application: Pocket, Portable, Bench
Citizen Chiba Precision frames the device plainly: a surface roughness tester "expresses roughness in numbers which cannot be judged by appearance," and the right pick depends on whether the user needs inline screening or documented QA [S8].
Three practical buckets line up against the 2026 catalog:
1) Pocket / wireless (PCE-RT 10 [S1], entry-level Biuged BGD 931 [S10]) — for shop-floor incoming inspection where the question is "is it inside the callout or not?" Suited to short traces, single Ra/Rz, no traceability stamp.
2) Portable piezoelectric (PCE-RT 1200 [S2], Mahr MarSurf M 310 [S3], Taylor Hobson Surtronic S100 / DUO [S6]) — for QA labs that need four parameters, Bluetooth data export, and ISO 4287 declarations. The DUO's separable handle is the differentiator for bores and recessed features.
3) Bench / confocal (REA-style areal scan [S7]) — for optics, glass, and research where 2D Ra is no longer representative.
Shandong Ipre Inspection Technology groups roughness testers with gloss meters, colorimeters, hardness testers, and ultrasonic thickness gauges as the standard portable metrology kit for Chinese OEMs, which mirrors the pocket-tier use case on production lines [S4].
Who It Is For — and Who Should Not Buy a Handheld
A handheld surface roughness tester is the right tool for: incoming inspection of turned, milled, and ground parts; spot checks on flange faces and hydraulic spool bores; shop-floor screening where Ra 0.8 / 1.6 / 3.2 μm callouts dominate; and paper-trail QA via Bluetooth or printer output [S2][S3].
It is the wrong tool for: optical-grade glass and mirror finishes, where areal Sa and the REA method dominate [S7]; micro-finished surfaces below Ra 0.05 μm, where stylus tip radius distorts the reading; and large cast-iron or shot-blasted surfaces with lay direction that violates ISO 4287's perpendicular-traverse assumption. For those, an optical profiler or a bench confoc
Closing trackable signals for the rest of 2026: (1) confirm whether the chosen model declares ISO 4287 / ASME B46.1 conformance in writing on the datasheet, not in marketing copy [S10]; (2) verify the stylus tip radius against the part material; (3) check Bluetooth or printer output for paperless / paper-trail compatibility with your existing earth ground tester and deadweight tester certificate workflows. China customs HS-code references remain in active rotation for surface roughness testers as of May 2026 [S5], so cross-border procurement still requires tariff code diligence.