- What This Cheat Sheet Covers (and What It Doesn't)
- Credential Snapshot: NIMS Classic Credential at a Glance
- How the Performance Evaluation Flows
- Grinding: Flats and Angles: The Core Competency
- Equipment and Material You Must Recognize
- Performance Assessment Worksheet Criteria
- The Four-Hour Timing Distinction
- Setup, Dressing, and Workholding Quick Reference
- Sine Bar and Angle Setup Reminders
- A Domain-Driven Prep Sequence
- Facts You Should Not Assume
- Frequently Asked Questions
- Grinding II (Surface) is a NIMS Classic Credential built around the competency heading Grinding: Flats and Angles.
- The practical performance assessment is required; multiple-choice study materials support knowledge review but never replace it.
- Worksheet criteria include flatness, squareness, parallelism, angularity, true position, radii, surface finish, and edge conditions.
- Wheel dressing is a graded performance standard, including radius and angle dressing for specified forms.
What This Cheat Sheet Covers (and What It Doesn't)
This page condenses the must-know facts for Classic Credential: Grinding II (Surface), the credential issued by the National Institute for Metalworking Skills (NIMS). It is built for last-pass review: the night before an evaluation, the morning of a lab session, or the week you decide which skills still need bench time.
One honest limit up front: the publicly available source material for this credential describes a performance assessment and its preparation scope. It does not publish a complete theory-exam blueprint with weighted domains, a question count, a timer, a passing score, or a fee. Rather than guess at those numbers, this sheet leaves them out. Everything below traces back to the evaluation instructions and performance standards for the competency heading Grinding: Flats and Angles.
Credential Snapshot: NIMS Classic Credential at a Glance
| Item | What the Source Material Supports |
|---|---|
| Credential name | Classic Credential: Grinding II (Surface) |
| Issuing body | National Institute for Metalworking Skills (NIMS) |
| Competency heading | Grinding: Flats and Angles (Machining Level II) |
| Assessment type | Practical performance evaluation against a candidate part print |
| Role of MCQ materials | Knowledge review support only; they do not replace the practical assessment |
| Domain weights | Not published in the available material |
| Theory question count, timer, pass score, fee | Not verified; omitted here |
For a plain-language introduction to the credential itself, see What Is Grinding II (Surface)? and the broader Grinding II (Surface) Certification overview.
How the Performance Evaluation Flows
The evaluation documents organize the experience into a predictable sequence. Knowing the sequence removes surprises on test day.
Evaluation Instructions: General Instructions
The general instructions point the candidate to the core working documents and resources for the job.
- The candidate part print
- Job instructions
- Evaluation criteria
- The tools, equipment, and materials provided or required
Monitoring the Performance
While you work, the evaluator observes safety and process, not just the finished part.
- Steel block specifications for the workpiece
- Safe workholding devices and tooling
- Personal protection and safety precautions
Completion of the Performance Evaluation
Finishing the part is not the end. The wrap-up is part of the evaluation.
- Cleanup of the work area
- Tool storage
- Equipment condition left after your work
- The evaluation worksheet and evaluation records
The practical implication: candidates who rush the final inspection or skip cleanup give away points that have nothing to do with grinding skill. Build cleanup and tool return into your practice runs.
Grinding: Flats and Angles: The Core Competency
The performance standards are organized under one heading, and every skill you practice should map to it. The standards cover:
- Materials and duty of the operation
- Dressing the wheel
- Finish surface grinding of flat surfaces at simple angles
- Specified radii and angled surfaces
- Following the process plan and part print specifications
- Precision finishing of surfaces, with attention to squareness, size, and surface finish characteristics
For a deeper walk through how this heading breaks down, the complete domains guide covers each element in detail.
Equipment and Material You Must Recognize
The assessment equipment list is long, and recognizing every item (and knowing when to reach for it) is a fast way to prevent hesitation during the evaluation. Group them by job:
| Function | Items Named in the Equipment List |
|---|---|
| Grinding and holding | Surface grinder with suitable magnetic chuck, magnetic sine chuck, precision grinding vise, angle plate, parallels, clamps, workstation |
| Angle setup and verification | Sine bars, inspection sine plates and/or sine bars, bevel vernier protractor, combination set, master square, magnetic square |
| Wheel preparation | Grinding wheels, diamond dresser, radius and angle dressers |
| Size measurement | Micrometers, depth micrometer set, vernier tools, calipers, gage blocks, adjustable parallels |
| Indicating and form checks | Dial test indicator, magnetic base for indicators, surface gage, surface condition comparison gages, Optical Comparator |
| Shop aids | Composition hammer, files |
Notice how many items serve inspection rather than cutting. Precision grinding is as much a measurement discipline as a machining one: gage blocks, sine tooling, and comparators exist because the tolerances demand verification at every stage.
Performance Assessment Worksheet Criteria
This is the heart of the cheat sheet. The performance assessment worksheet names what the evaluator checks on your finished part:
- Dimensional tolerances
- Slots
- Radii
- True position
- Angularity
- Flatness
- Perpendicularity
- Parallelism
- Surface finish
- Edge conditions
- Absence of milling marks
Key Takeaway
The "absence of milling marks" criterion is easy to overlook. Surfaces the print calls for as ground must show a ground finish, with no leftover evidence of the earlier milling operation. Plan enough stock removal in your grinding passes to clean up each surface fully, and check under good light before you declare a face finished.
Each criterion maps to a habit:
- Flatness: sharp, freshly dressed wheel; light final passes; stable workholding with no chuck distortion.
- Parallelism and perpendicularity: grind a reference face first, then use it to locate the opposing and adjacent faces.
- Angularity: set angles with sine tooling, verify with a bevel protractor or sine plate before the finishing pass.
- Radii: dress the form into the wheel with the radius dresser, and confirm with the comparator or radius check.
- Edge conditions: treat edges as specified on the print; do not leave burrs, and do not break edges beyond what the print allows.
If you want to understand how hard these criteria are in practice, read How Hard Is the Grinding II (Surface) Exam?
The Four-Hour Timing Distinction
Two statements in the source material look contradictory until you read them carefully:
- The part print identifies a four-hour completion time.
- The evaluation instructions treat performance times as guidelines.
A practical approach: time your practice runs against four hours, and track where time goes. Most candidates lose minutes in setup, re-indicating, and re-dressing, not in the actual grinding passes. Tightening those transitions is the easiest way to gain a cushion.
Setup, Dressing, and Workholding Quick Reference
The credential's preparation scope specifically calls out setup, dressing, workholding, inspection, and precision finish and tolerance requirements. Here is a compact checklist for each.
Setup
Get the machine and workpiece into a known, verified state before any finishing pass.
- Read the print and process plan; decide the grinding sequence.
- Confirm the magnetic chuck is clean and free of burrs or debris.
- Verify the steel block against stock specifications.
- Gather and stage gage blocks, sine tooling, and indicators before starting.
Dressing
Dressing the wheel is a named performance standard, not a background chore.
- Use the diamond dresser for general wheel conditioning.
- Use radius and angle dressers when the print requires a formed wheel.
- Re-dress when the wheel loads, glazes, or fails to hold the form.
- Dress before finish passes so the surface finish requirement is achievable.
Workholding
Safe workholding devices and tooling are evaluated during monitoring.
- Choose between magnetic chuck, magnetic sine chuck, precision vise, or angle plate based on the feature being ground.
- Use parallels and clamps to support and restrain the work as the setup requires.
- Check that the part cannot shift or lift under the cutting load.
- Never rely on magnetic holding alone for a poorly supported or low-contact setup.
Inspection
Measure early and often rather than only at the end.
- Confirm size with micrometers or gage block comparison.
- Check squareness with a master or magnetic square.
- Verify angles with sine bars, inspection sine plates, or a bevel vernier protractor.
- Use surface condition comparison gages for finish checks.
Sine Bar and Angle Setup Reminders
Angled surfaces are central to the credential, so keep the fundamentals sharp. The sine bar principle is simple: the sine of the desired angle equals the height built with gage blocks divided by the distance between the sine bar's rolls. Rearranged, the gage block stack height equals the roll center distance multiplied by the sine of the angle.
- Know the center distance of the sine bar you are using before you calculate anything.
- Build the gage block stack carefully, and wring the blocks properly.
- Verify the setup with an indicator across the angled face: the indicator reading should show no variation along the surface.
- When using a magnetic sine chuck, confirm the angle lock and the stop before energizing the chuck.
Key Takeaway
An angle you calculated is only a theory until you indicate it. Always verify the setup by indicating the surface before the first cut. A few minutes spent confirming angularity prevents the far more costly mistake of grinding a whole face to the wrong angle.
A Domain-Driven Prep Sequence
Because the credential is performance-based and organized around one competency, prep works best when it follows the sequence of the work itself. Here is one way to schedule it, tied directly to the standards above. For broader preparation strategy, see the Grinding II (Surface) Study Guide.
Print Reading and Measurement
- Practice reading part prints for tolerances, radii, and angles.
- Review the full equipment list and what each measuring tool resolves.
- Drill gage block stacking and sine bar calculations.
Setup, Workholding, and Dressing
- Practice flat grinding with parallelism and flatness checks.
- Rehearse dressing, including radius and angle forms.
- Run safety and monitoring routines until they are automatic.
Full Timed Part and Self-Evaluation
- Grind a complete part against a four-hour benchmark.
- Score yourself against every worksheet criterion.
- Practice cleanup, tool storage, and evaluation records.
Knowledge-check questions can help reinforce vocabulary, terminology, and calculations along the way. Use the practice test site for that review, keeping in mind that multiple-choice study materials support knowledge review but do not substitute for the required practical assessment.
Facts You Should Not Assume
Because this credential's public documentation is narrower than people expect, several commonly searched details cannot be stated with confidence. Be careful with:
- Fees and cost: not verified in the available material. See Grinding II (Surface) Certification Cost for how to approach budgeting without relying on unverified numbers.
- Passing score: not verified. The passing score guide explains what is and is not known.
- Pass rates and salary figures: not published in the source material, so treat any precise figure you encounter elsewhere skeptically.
- Exam dates and scheduling: handled through your assessment administrator; check the exam dates article for guidance on what to ask.
- Eligibility and prerequisites: see the requirements article and confirm with NIMS or your testing site.
For career context, including who values this credential, the Grinding II (Surface) Jobs article and the worth-it analysis cover the practical side without inflating the numbers.
Frequently Asked Questions
The National Institute for Metalworking Skills (NIMS) issues and retains this exact Classic Credential. Official details are published on the NIMS classic credentials pages and in the Grinding Level 2 Surface Grinding documents.
The available source material centers on a practical performance assessment under the competency heading Grinding: Flats and Angles. Multiple-choice study materials can support knowledge review, but they do not replace the required practical assessment.
The part print identifies a four-hour completion time, while the evaluation instructions treat performance times as guidelines. Practice against four hours, and confirm with your assessment administrator how timing is applied.
The performance assessment worksheet covers dimensional tolerances, slots, radii, true position, angularity, flatness, perpendicularity, parallelism, surface finish, edge conditions, and the absence of milling marks.
None were verified in the available official material, so none are stated here. Treat any specific figures from unofficial sources with caution, and confirm details directly with NIMS or your testing site.