Roughness Testers

The collection carries six instruments across three trusted brands. Mahr contributes two instruments: the Pocket Surf IV portable roughness gage (models 2191802 and 2191800) and the MarSurf PS10 Set with 5µm probe. Starrett contributes the SR160 Surface Roughness Tester with Bluetooth. Phase2+ contributes three instruments spanning different capability tiers: the SRG-2200 mini handheld roughness tester, the SRG-4000 portable profilometer, and the SRG-4600 flagship portable profilometer. Together they cover the full range of shop-floor surface roughness measurement needs from fast single-parameter Ra checks to comprehensive multi-parameter profilometry with Bluetooth and USB data output.

Surface roughness is the quantification of the microscopic peaks and valleys left on a part surface by machining, grinding, turning, milling, or other manufacturing processes. It matters because surface texture directly affects how a part performs in service bearing surfaces with excessive roughness cause accelerated wear; sealing surfaces that are too rough leak; medical implant surfaces must meet specific texture requirements for tissue compatibility; aerospace structural parts have surface finish specifications tied to fatigue life. Measuring surface roughness with a calibrated profilometer provides traceable numerical values Ra, Rz, Rq, Rt, and others that can be compared against engineering drawing tolerances, documented for quality records, and used to tune machining processes before defective parts are produced.

Each parameter characterizes a different statistical aspect of the surface profile. Ra (Arithmetic Mean Roughness) is the most universally specified and it is the arithmetic average of the absolute height deviations of the profile from the mean line over the evaluation length, expressed in micrometers or microinches. It gives a single representative number for overall surface texture that is intuitive and directly comparable. Rz (Mean Roughness Depth) is the average of the five highest peak-to-valley heights within the evaluation length more sensitive than Ra to occasional extreme surface features. Rq (Root Mean Square Roughness) is the square root of the average of the squared deviations, statistically equivalent to the RMS roughness, slightly more sensitive to peaks and valleys than Ra. Rt (Total Height of Profile) is the total height from the highest peak to the lowest valley across the entire evaluation length a worst-case indicator. Most engineering drawings specify Ra or Rz; the instruments in this collection measure all four plus additional parameters depending on the model.

The Mahr Pocket Surf IV (models 2191802 and 2191800) is Mahr's compact, battery-powered handheld roughness gage designed for single-button, fast surface finish evaluation directly at the machine, on the production line, or at incoming inspection. Its defining characteristics are simplicity and speed: the large high-contrast digital display delivers an immediate Ra reading without multi-step setup or parameter scrolling, making it the right tool when an operator needs a quick pass/fail surface finish check after machining and wants the instrument in their hand rather than on a bench. The 2191802 features a 5µm radius stylus (EGH-1026) for standard surface measurement, and the 2191800 is the alternate model variant. Both are backed by Mahr's 160+ years of precision metrology manufacturing.

The Mahr MarSurf PS10 Set (6910232) is a higher-capability portable surface roughness tester bundled as a complete set with a 5µm radius probe, carrying case, calibration standard, and measurement documentation. Where the Pocket Surf IV is optimized for speed and simplicity with a focused Ra output, the MarSurf PS10 supports a broader parameter set and is better suited for applications that require documentation, reporting, and measurement of multiple surface texture parameters beyond a single Ra value. The PS10's compact but full-function design makes it appropriate for quality labs that need portability without sacrificing the parameter coverage and reporting capability of a bench-top instrument. Both carry Mahr's calibration traceability and precision manufacturing quality.

The Starrett SR160 is a shop-hardened portable surface roughness tester featuring a protected piezoelectric pickup with a diamond tip stylus, a color on-screen graph display showing multiple parameters simultaneously, and two-piece Bluetooth connectivity for wireless data transfer. Its rechargeable lithium-polymer battery is rated for over 10,000 measurements per charge, a standout specification that eliminates battery anxiety in high-volume inspection environments where recharging interrupts workflow. Both skidded and skidless measurement modes are supported, and the parameter set includes Ra, Rz, Rp, Rv, Rt, RZ1Max, Rsk, Rq, Rku, Pa, Pz, Pp, Pv, and Pt one of the most comprehensive parameter sets available in a portable instrument at this tier. The SR160 is shock-tested and built for the demands of aerospace, automotive, safety, and general manufacturing shop floors.

The Phase2+ SRG-2200 is Phase2+'s next-generation mini portable surface roughness tester, a compact, Bluetooth-equipped instrument designed to function on a wide variety of surface geometries beyond flat planes. It measures flat surfaces, outer cylinders, outer cones, grooves, and recesses greater than 80×30mm, with parameters Ra, Rz, Rq, and Rt selectable via the 1.14" IPS TFT color display. Built-in calibration capability allows external calibration of surface roughness values using a reference standard directly on the instrument. Bluetooth data output to PC or mobile device enables paperless documentation of results with large internal memory for storing measurements. The SRG-2200 is purpose-built for inspection departments, quality control rooms, shop floor in-process checking, and on-site measurement tasks where versatility across part geometries is as important as portability.

The SRG-4600 is Phase2+'s flagship portable surface roughness tester and the most capable instrument in the Phase2+ roughness lineup. It supports nine roughness parameters (Ra, Rz, Rq (RMS), Rt, Rs, Rsm, Rmax, Rpc, and Rmr) a significantly broader set than the SRG-2200's four parameters. Its inductance-type sensor with a 5µm diamond stylus achieves a display resolution of 0.001µm, measuring Ra/Rq from 0.01–40µm and Rz/Rt/Rm from 0.02–160µm. Selectable digital filters (RC, PC-RC, Gaussian, D-P), three cutoff lengths (0.25/0.8/2.5mm), and three tracing speeds provide the configuration flexibility that ISO, DIN, JIS, and ANSI standards require. USB and Bluetooth data output connect the instrument to PC software or SPC systems. The SRG-4000 sits between the SRG-2200 and SRG-4600 in capability and parameter count. Choose the SRG-4600 when the surface finish specification on the drawing requires parameters beyond Ra, when the quality system requires filter and cutoff length selection, or when traceable documentation of multiple parameters is mandatory.

Surface roughness testers in this collection serve across aerospace (fatigue life-sensitive structural surfaces, landing gear components, bearing journals), automotive (engine cylinder bores, crankshaft bearing surfaces, transmission gears, sealing faces), medical device manufacturing (implant surfaces, surgical instrument finish specs, sterile packaging seal integrity), precision machining (ground, turned, milled, and honed parts to drawing finish specifications), hydraulics and pneumatics (cylinder bore and piston rod surfaces where leak-tightness depends on finish), and electronics manufacturing (connector contact surfaces, heat sink interfaces). Any part where surface texture is a controlled dimension on an engineering drawing and not just a cosmetic requirement is a candidate for profilometer measurement.

All roughness tester orders ship free to the continental USA, backed by a best-price guarantee. A 30-day return policy and Affirm financing at checkout are available. Government agencies, aerospace suppliers, and regulated manufacturers can submit an RFQ through the dedicated Government RFQ page (DUNS: 13-715-2209, CAGE: 15F67). Roughness tester selection depends on the parameter set required by the drawing specification, the surface geometries to be measured, the need for Bluetooth or USB data output, and whether a simple pass/fail Ra check or a fully documented multi-parameter profilometry report is required. Gustavo personally reviews every order and is available to help match the right instrument to the application simply call or text 617-398-7852, Monday through Friday, 8am–5pm EST.