What Is A Grinding II (Surface)?

What the Credential Actually Is

A Grinding II (Surface) is a performance-based credential from the National Institute for Metalworking Skills, better known as NIMS. It sits in NIMS's catalog of Classic Credentials, and it recognizes a machinist's ability to produce precision ground surfaces on a real workpiece, not just to answer questions about grinding.

That distinction matters for how you prepare. Many people searching for this credential expect a conventional multiple-choice test with a question count, a timer and a published passing score. The source material available for this credential does not describe that. What it describes is a hands-on evaluation: you are handed a part print and job instructions, you set up a surface grinder, and an evaluator checks your finished part against defined criteria.

If you want the broader landscape of what the credential covers, our companion pieces on what Grinding II (Surface) is and Grinding II (Surface) certification approach the same topic from adjacent angles.

Decoding the Name: Grinding, Level II, Surface

Each word in the title carries meaning, and understanding them clears up most of the confusion around this credential.

Grinding

Grinding is an abrasive machining process that removes material with a bonded abrasive wheel. It is the finishing operation of choice when a part needs tighter size control, better flatness and a finer surface than milling or turning can reliably deliver.

Level II

The "II" places this credential above entry-level grinding work. The NIMS evaluation documents for this credential are titled around Machining Level II, so the expectation is a candidate who already knows how to run a grinder safely and can now hold meaningful geometric tolerances: squareness, angularity, parallelism and flatness, not just a rough stock removal.

Surface

Surface grinding produces flat (and, in this case, simply angled or radiused) surfaces on a workpiece held on a magnetic chuck or in a fixture. This is distinct from cylindrical or centerless grinding, which deal with round work. The credential is specifically about flat and angled surfaces.

If you are comparing terms, see also our explainers on what Grinding II (Surface) means and what it stands for.

How the Credential Is Assessed

The assessment is organized around a structured evaluation package. Based on the source documents, the package includes several distinct components that a candidate should recognize before test day.

Notice how much of this is process, not just product. A candidate who grinds a beautiful part but neglects safety, leaves the machine dirty or stores tools carelessly is leaving points on the table. For a deeper look at how the pieces fit together, read our complete guide to the Grinding II (Surface) content areas.

The Competency Area: Grinding: Flats and Angles

The scope of this credential is organized under a single competency heading: Grinding: Flats and Angles. Everything a candidate needs to master hangs from that heading. In practical terms, that means being able to take a steel block and, following a process plan and the part print, produce:

• Finish-ground flat surfaces
• Flat surfaces at simple angles
• Specified radii
• Angled surfaces that meet the print

The performance standards also call out materials, duty and dressing the wheel as explicit items. That last one is easy to underestimate. A wheel that has not been properly dressed will load, glaze or cut inconsistently, and no amount of careful handwheel work will rescue the finish. Dressing is a core skill here, not an afterthought, and the equipment list includes diamond dressers plus radius and angle dressers for forming the wheel itself.

Equipment and Materials You Must Know

The assessment equipment list is long, and familiarity with every item is part of being ready. It breaks naturally into workholding, grinding setup and inspection.

Two groupings deserve special attention. First, the sine-based tools: setting up an angled surface accurately depends on knowing how to build a sine bar stack with gage blocks and verify the result. Second, the inspection group: you are expected to measure your own work against the print, which means choosing the right instrument for each feature and reading it correctly.

Performance Standards: What the Worksheet Rewards

The Performance Assessment Worksheet is where your work is ultimately judged. Its criteria cover both dimensional and geometric characteristics. Here is how they group.

The "absence of milling marks" criterion is a telling one. It signals that the part likely arrives with prior machining and that your grinding must fully clean up those marks while still hitting size. That requires planning your stock removal so you have enough material to clean up without going undersize.

The Timing Question: Guideline vs. Print

One subtle point in the source material is worth preserving rather than smoothing over. The evaluation instructions treat performance times as guidelines. Separately, the part print itself identifies a four-hour completion time. These two statements are not identical in spirit, and a candidate should hold both in mind.

Practically, this means rehearsing the job in segments: setup, dressing, rough and finish passes, angle work, inspection and cleanup. If any one segment regularly blows past its share of the four hours, that is where to focus. Our article on how hard the Grinding II (Surface) exam is discusses where candidates tend to feel pressure.

Who Pursues This Credential

The credential suits people who work, or want to work, where precision flat and angled surfaces are routine: tool and die shops, mold and fixture makers, general precision machining and inspection-heavy manufacturing. Apprentices and journeyman-track machinists use NIMS credentials to document skills that a résumé line alone cannot prove, and training programs often align coursework to these standards so graduates leave with a recognized, performance-verified credential.

We do not cite salary figures or hiring statistics here because none are verified for this credential. If you are weighing the return, our pieces on whether the certification is worth it, Grinding II (Surface) jobs and the salary guide walk through the considerations qualitatively.

Sequencing Your Preparation

Rather than a generic schedule, order your preparation by the dependency chain of the work itself. Each stage supports the next, so earlier weeks should lock in the skills later weeks rely on.

Knowledge-review questions can help reinforce terminology and theory between shop sessions, but they supplement the practical assessment rather than replace it. You can use the Grinding II (Surface) practice tests for that review, and pair them with our full study guide and the one-page cheat sheet.

Frequently Asked Questions