Grinding II (Surface) Pass Rate 2026: What the Data Shows

Why There Is No Published Pass Rate for Grinding II (Surface)

If you searched for a pass rate for Classic Credential: Grinding II (Surface), you probably hoped for a clean number: "X percent of candidates pass on the first attempt." That number would be convenient, but the source material for this credential does not support one. The National Institute for Metalworking Skills (NIMS) retains and administers the credential, and the documents describing it focus on how the performance is evaluated, not on aggregate outcome statistics.

This article takes a different approach. Instead of inventing a figure, it examines what the available evidence does show: what the assessment measures, which parts of the evaluation are most likely to cost a candidate points, and how to prepare so that your own result is not left to chance. For a broader look at the credential's structure, see our complete guide to the Grinding II (Surface) exam domains.

What the Credential Actually Assesses

Grinding II (Surface) is a practical credential. The scope covers surface grinding preparation and execution: setup, wheel dressing, workholding, inspection, and meeting precision finish and tolerance requirements. The competency heading in the NIMS materials is Grinding: Flats and Angles, and that single heading organizes everything a candidate is expected to demonstrate.

Because the source material provides an unweighted performance-assessment scope rather than a full theory-exam blueprint, you should not expect a neat table of percentage-weighted domains. Theory question count, timer, pass score and fee were not verified, so this article does not state them. If you need a refresher on the basics of the credential itself, start with What Is Grinding II (Surface)?

Where Candidates Lose Points

The Performance Assessment Worksheet is the clearest window into what separates a passing part from a failing one. Its criteria include dimensional tolerances, slots, radii, true position, angularity, flatness, perpendicularity, parallelism, surface finish, edge conditions and the absence of milling marks. That is a long list, and a part can miss on any single item.

Geometry Errors Compound Each Other

Surface grinding punishes sloppy setup. If the workpiece is not seated cleanly on the magnetic chuck, parallels or angle plate, every downstream feature inherits the error. A part that is slightly out of parallel will often also be out of size and out of square. Candidates who rush the setup tend to spend the remaining time chasing errors they baked in at the start.

Angles Demand Calculation Discipline

The equipment list includes a magnetic sine chuck, sine bars, inspection sine plates, a bevel vernier protractor and gage blocks. Those tools exist because angled surfaces require you to calculate a sine bar stack and then verify the result. A transposed digit in a gage block stack produces a perfectly ground, perfectly wrong angle.

Surface Finish and Edge Condition

Finish is evaluated, not assumed. The worksheet specifically lists surface finish, edge conditions and the absence of milling marks. A dull or loaded wheel, an under-dressed wheel, or a feed that is too aggressive will leave marks that an evaluator can see immediately. Surface condition comparison gages are listed among the assessment equipment precisely so finish can be judged against a reference.

The Timing Distinction: Guideline vs. Print

One detail in the source material deserves careful attention. The evaluation instructions treat performance times as guidelines. At the same time, the candidate part print identifies a four-hour completion time. These two statements are not identical in meaning, and the distinction is worth preserving rather than smoothing over.

In practical terms, do not assume that "guideline" means you have unlimited time, and do not assume that the four-hour figure is a hard cutoff without confirming how your assessment site applies it. Ask your evaluator or training provider how timing is handled before assessment day. Planning your work around the four-hour figure is the safer preparation strategy, because it forces you to build a realistic sequence of operations. Our guide on how hard the Grinding II (Surface) exam is explores how time pressure interacts with precision work.

Equipment Readiness and Inspection Tools

The assessment equipment list is extensive, and familiarity with each item affects both your speed and your accuracy. The list includes a surface grinder with a suitable magnetic chuck, a magnetic sine chuck, sine bars, parallels, an angle plate, a precision grinding vise, clamps, a composition hammer, grinding wheels, files, a magnetic base for indicators, a surface gage and a diamond dresser. Inspection tools include micrometers, a combination set, dial test indicators, vernier tools, calipers, gage blocks, adjustable parallels, a depth micrometer set, a master square, a magnetic square, and an optical comparator.

The optical comparator is worth singling out. Radii and angled profiles are the sort of feature it is designed to verify, and candidates who have never used one often hesitate when it appears on the list. Likewise, radius and angle dressers are specialized items; knowing when and how to use them is a skill separate from simply operating the grinder.

Safety and Process Are Part of the Evaluation

The Monitoring the Performance portion covers steel block specifications, safe workholding devices and tooling, personal protection and safety precautions. The Completion of the Performance Evaluation portion covers cleanup, tool storage, equipment condition, the evaluation worksheet and evaluation records. In other words, you are assessed on how you work and how you leave the machine, not only on the finished part. A dimensionally perfect block does not erase a safety lapse or a messy workstation.

A Domain-Driven Prep Sequence

Because the credential has a single competency heading, the most useful way to organize preparation is by the stages of the job itself rather than by abstract topics. Here is one sequence that follows the performance standards in order of dependency.

This order is deliberate: planning errors are the cheapest to fix, setup errors are the most expensive to discover late, and angle work benefits from solid fundamentals first. For a fuller walkthrough, our Grinding II (Surface) study guide expands on each stage, and the one-page cheat sheet is handy for last-minute review.

Reading Pass-Rate Claims Critically

When you encounter pass-rate numbers for any credential, a few questions separate useful data from noise. The table below applies that lens to Grinding II (Surface) based strictly on what the source material supports.

If you want more on scoring, see our discussion of the Grinding II (Surface) passing score, and for cost planning, the certification cost breakdown. Where a specific figure was not verified, those pages should be read with the same caution applied here.

Who Values This Credential

Surface grinding sits in the precision end of manufacturing, where flatness, parallelism and finish are specified in tolerances that other processes struggle to hold. Shops that produce tooling, dies, molds, gages and precision components rely on grinding to bring parts to final size and finish. A NIMS credential gives a hiring manager a standardized, third-party signal that a candidate has demonstrated hands-on skill against a defined evaluation rather than simply describing it on a resume.

We do not cite salary numbers here because none were verified for this credential. If you are weighing career value, our pieces on Grinding II (Surface) jobs, the salary guide and whether the certification is worth it discuss the considerations qualitatively.

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