What Is Grinding II (Surface) Certification?

What the Credential Actually Is

Classic Credential: Grinding II (Surface) is a NIMS credential that recognizes a machinist's ability to produce precision flat and angled surfaces on a surface grinder. It is the second tier in the NIMS grinding progression, and it is built around demonstrated skill rather than memorized trivia. A candidate is expected to read a part print, plan the process, set up the machine, dress the wheel, hold the work safely, grind to size and finish, and then prove the result with inspection tools.

If you have seen the acronym used for other credentials elsewhere, set that aside. This article covers only the NIMS Classic Credential, and the details below come from the NIMS evaluation documents for Grinding Level 2 (Surface Grinding). For a broader orientation on terminology, our companion pieces What Is Grinding II (Surface)? and Grinding II (Surface) Meaning cover the naming and context in more depth.

Who Issues It and Where to Verify Details

The issuing body is the National Institute for Metalworking Skills, commonly called NIMS. NIMS maintains the Classic Credentials catalog and the credential listings in its credentialing system, and it publishes the Grinding Level 2 evaluation documents that define what a candidate must demonstrate. Because NIMS retains the exact credential and its assessment materials, the NIMS site is always the authoritative reference for current logistics.

How the Assessment Works: Performance First

The defining feature of this credential is that it is a performance assessment. You are given a candidate part print, job instructions, and evaluation criteria, then you complete the work at a real workstation while an evaluator observes. The evaluation instructions are organized around several stages:

• General instructions: the candidate part print, job instructions, evaluation criteria, and the tools, equipment and materials you will use.
• Monitoring the performance: the evaluator watches steel block specifications, safe workholding devices and tooling, personal protection, and safety precautions.
• Completion of the performance evaluation: cleanup, tool storage, equipment condition, the evaluation worksheet, and evaluation records.

Notice what is being graded beyond the finished part. Safety, workholding choices, how you leave the machine, and how you store your tools are all part of the evaluation. Candidates who focus only on hitting the dimensions sometimes forget that housekeeping and safe practice are scored too.

Where Multiple-Choice Study Material Fits

Multiple-choice questions can be a useful way to review terminology, wheel selection logic, inspection concepts and safety knowledge. They do not substitute for the practical assessment, and nothing in the available source material defines an official theory exam structure for this credential. Use MCQ practice as a supplement to bench time, not a replacement. You can find knowledge-review practice on the main practice test site, and our Grinding II (Surface) Study Guide shows how to combine it with hands-on repetition.

The Competency Area: Grinding: Flats and Angles

The published scope is organized under a single competency heading, Grinding: Flats and Angles, within Machining Level II. There is no weighted multi-domain blueprint in the source material, so rather than invent percentages, it is more useful to understand what the heading contains.

For a deeper walk-through of how this single competency area breaks down, see our Grinding II (Surface) Exam Domains guide.

Performance Standards You Will Be Measured Against

The performance standards describe the actual technical work. They cover materials, duty, dressing the wheel, and finish surface grinding of flat surfaces at simple angles, specified radii and angled surfaces. You are expected to follow the process plan and part print specifications and to deliver precision finishing of surfaces with attention to squareness, size and surface finish characteristics.

Dressing the Wheel

Wheel dressing is called out explicitly, and it is more than a preliminary step. A properly dressed wheel is what lets you hold size, achieve the surface finish the print demands, and generate accurate angles and radii. The assessment equipment list includes a diamond dresser along with radius and angle dressers, which signals that you may be expected to form specific wheel profiles rather than only true a flat face.

Flats, Angles and Radii

Flat grinding is the foundation, but this credential goes further. You will work angled surfaces, which is why sine-based tooling appears throughout the equipment list, and specified radii, which depend on correct wheel forming and careful stock management. Reading the print accurately and sequencing operations so that one surface does not compromise another is a core skill.

Equipment and Materials You Should Know Cold

The assessment lists a substantial set of equipment, and being fluent with it saves time and prevents errors. You should be comfortable selecting and using each item.

A magnetic sine chuck paired with accurate gage block stacks is a classic way to set a precise angle, so be ready to calculate sine bar heights and verify the setup with an indicator. The presence of an Optical Comparator in the list also tells you that profile and radius features may be checked visually against a reference, not only with contact gages.

What the Performance Assessment Worksheet Checks

The worksheet is where your finished part is judged. The criteria named in the source material include:

• Dimensional tolerances
• Slots and radii
• True position
• Angularity
• Flatness
• Perpendicularity
• Parallelism
• Surface finish
• Edge conditions
• Absence of milling marks

The last two deserve special attention. Edge conditions mean burrs and breaks are inspected, so deburr deliberately without altering critical dimensions. The absence of milling marks means the ground surfaces must be clean of any prior machining evidence, which puts pressure on your stock removal strategy and your final finishing passes.

The Timing Distinction: Guideline vs. Part Print

The source material contains a subtle but important timing detail. The evaluation instructions treat performance times as guidelines, meaning evaluators are not instructed to use time as a rigid cutoff in the way a timed written test would. Separately, the part print identifies a four-hour completion time. These two statements coexist, and the honest reading is to preserve both: plan to work efficiently toward the four-hour figure on the print, while understanding that the evaluation guidance frames timing as a guideline rather than an absolute pass or fail line.

In practice, do not rely on the flexibility. Practice finishing within four hours so that unexpected issues, such as a wheel that needs re-dressing, do not push you into rushed decisions. Confirm the exact timing expectations with your NIMS-affiliated test site before assessment day. For how this fits into the larger question of difficulty, read How Hard Is the Grinding II (Surface) Exam?

Who Benefits From This Credential

Surface grinding is a precision finishing skill, so the credential is relevant wherever tight-tolerance flat and angled surfaces are required. That includes tool and die operations, mold and fixture work, precision machining job shops, and manufacturers that need ground reference surfaces on components. Employers in these settings value a candidate who can read a print, set up a grinder safely, and prove accuracy with proper inspection tools.

Apprentices and working machinists often pursue the credential to document skills that are otherwise hard to show on a resume. We do not cite specific salary figures here because none are verified in the source material; for a qualitative discussion see our salary guide, our look at Grinding II (Surface) jobs, and the broader worth-it analysis.

A Domain-Driven Prep Sequence

Since the credential is one competency area with several distinct skill clusters, the most useful way to schedule preparation is by skill cluster rather than by generic weekly templates. Here is one sequence that follows the way the assessment itself unfolds.

For a compact reference to keep at your bench, see the Grinding II (Surface) Cheat Sheet, and for eligibility questions, our requirements guide and exam dates page explain what to confirm with your testing site.

Frequently Asked Questions

To go deeper on specific areas, explore our guides on Grinding II (Surface) certification, what the certification involves, and training options.