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newSchoolWorks.com › VoTechWorks › Building & Construction › Heavy Equipment Operation › Motor Grader Operation › Lesson 5
BLD-HEAV08-05 · Lesson 5 · 10 clock hours · field

Roadway Shaping: Crown, Ditch, and Capstone Grading Project

Objective. Students will shape a 150-foot road section to a specified crowned cross-section and an adjacent v-ditch to plan dimensions through a multi-pass sequence, then complete and submit a finalized lab log documenting the full grading operation.

⚠ Pending professional review

This lesson, its worked examples and its practice questions has not yet been verified by a licensed professional engineer or master tradesperson or by a certification or approval body. It is a study draft and may contain errors. Do not use it as instructions for work on a job site or on live equipment. Always follow your instructor, your supervising professional, and current official references and regulations.

VoTechWorks program approval and accreditation are still in progress. Credentials are issued only by the certifying bodies named in each program, after their own exams.

Roadway Shaping: Crown, Ditch, and Capstone Grading Project

This lesson brings together every motor grader skill you have practiced into one integrated field project. You will shape a 150-foot road section to a specified crowned cross-section and cut an adjacent v-ditch to plan dimensions. A completed lab log documents the full operation. This is your capstone: accuracy, planning, and professionalism all count.

Why Crown and Ditch Work Together

A crowned road surface sheds water toward its edges. Without a ditch to collect and carry that water away, it pools at the shoulder and weakens the subgrade. The crown and the ditch are a system. When you grade one, you must think about the other. A typical gravel road crown rises from each edge toward the centerline at a consistent cross-slope, often in the range of two to four percent, though your instructor will give you the exact design value for this project. The adjacent v-ditch intercepts runoff at the toe of the shoulder and channels it away.

The Multi-Pass Sequence

No grader operator shapes a crowned road in a single pass. Planning your passes before you move the machine saves time and produces a better result.

Pass 1 – Centerline reference cut. Start at the centerline with a shallow cut. This establishes your high point and gives you a reference line for all subsequent passes. Keep the blade nearly perpendicular to the direction of travel and remove only what is needed to define the center.

Passes 2 and 3 – Material pull from edges. Angle the blade to pull windrow material from the outer edge inward toward the centerline. Work from both sides. The goal is to build up the crown profile progressively. Blade angle is typically set between 25 and 45 degrees from perpendicular to move material efficiently. Check your cross-slope with a level or smart-level app after these passes to see how close you are to the design value.

Ditch formation passes. Shift your working position to the ditch side. Lower the blade tip to cut downward and inward to form the v-shape. The blade circle may be rotated to help match the specified side slope. Make overlapping passes until depth and slope match plan dimensions. Keep the machine tires well away from the ditch edge to avoid caving the wall.

Finish pass – Travel surface. Use a low blade angle and a very light cut for the final pass on the travel surface. This smooths ridges, seals small irregularities, and gives the road its finished appearance. Slow ground speed and steady hydraulic inputs are essential here. Jerky corrections show up in the final surface.

Blade Settings and Controls

Three blade adjustments work together on every crown and ditch pass:

For crown work, set the left and right lift cylinders slightly differently so the blade tilts to match the design cross-slope as you make pull passes. For the finish pass, reduce pitch and minimize the height difference between the two cylinders.

Measuring What You Built

After your finish pass, check your work at three locations: at each end of the 150-foot section and near the midpoint. At each location:

1. Lay a 10-foot straightedge across the road surface perpendicular to the centerline.

2. Place a cross-slope level or tablet with smart-level app on the straightedge.

3. Record the percent slope reading.

4. Measure the v-ditch depth from the shoulder break point and check the side slopes with your tape and level.

Your crown must be within 0.5 percent of the design slope at all three points. Ditch depth and side slopes must match plan dimensions within one inch.

Safety on the Grading Site

Pre-operation inspection. Complete your full pre-op check before you start the engine. Record any findings in your lab log. Do not operate a machine with a safety defect—report it to your instructor immediately.

Bystander and observer distance. During student operation, all non-operating students must remain outside the swing and travel radius of the machine. The cab observer seat is only used during instructor demonstration. When you are running the machine, no additional riders are permitted unless your training program specifically authorizes it.

Ditch edge hazard. Never position the machine so that tires overhang or track too close to the ditch edge. Soft or freshly cut soil can collapse. Keep at least one full tire width of clearance from the cut edge.

PPE required: Hard hat, high-visibility vest, safety-toed boots, and eye protection are required on the grading site at all times. Hearing protection is required when in or near operating equipment.

Machine shutdown. When leaving the cab for any reason—measurements, grade stake checks, or breaks—lower the blade fully to the ground, set the parking brake, and shut the engine down. Never leave a running machine unattended.

Lab Log and Reflection

Your lab log for this session is the final section of your full course packet. Complete every field: total machine hours operated, pre-op findings from each session, blade settings used for crown and ditch passes, elevation check results from Lesson 4, and your written reflection. The reflection must identify one technique that improved over the course and one that still needs practice. Be specific—name the blade adjustment, the pass type, or the measurement skill. Vague answers do not meet the standard.

This documentation habit matters beyond school. NCCER performance tasks require operators to demonstrate they can plan, execute, and self-evaluate their work. Employers expect operators who know what they did and why.

Key terms9

CrownThe slight convex arch built into a road surface from edge to centerline that causes water to drain toward the sides rather than pooling on the travel surface.
Cross-slopeThe percent grade measured perpendicular to the road centerline; used to specify and verify both the crown profile and ditch side slopes.
V-ditchA drainage channel cut adjacent to a road with two straight side slopes meeting at a point at the bottom, used to collect and carry runoff away from the travel surface.
Blade angle (circle rotation)The horizontal angle of the motor grader's blade relative to the machine's direction of travel, adjusted by rotating the blade circle; controls how far and in what direction material is cast.
Blade pitch (top-tilt)The forward or backward tilt of the cutting edge; a forward pitch increases cutting aggressiveness while a backward pitch floats and smooths material.
Finish passThe final grading pass over a completed surface made with a light cut, low blade angle, and slow ground speed to smooth ridges and seal the surface.
Blade overlapThe lateral distance by which successive grader passes share a common strip of the work surface, ensuring no uncut ridges are left between passes.
Grade stakeA stake set by a surveyor or grade-setter indicating the design elevation and cut or fill amount at that point; the operator uses these to control blade height.
WindrowA ridge of loose material pushed to one side by the blade during a grading pass; it is then redistributed in subsequent passes to build the finished profile.

Worked examples4

1. Your design calls for a 3.0% crown cross-slope. After your finish pass you lay a 10-foot straightedge across the road surface and read 2.6% on the smart-level app. Is this within tolerance, and by how much?
  1. Step 1: Identify the tolerance. The spec requires the measured cross-slope to be within 0.5% of the design slope.
  2. Step 2: Calculate the difference. Design slope − measured slope = 3.0% − 2.6% = 0.4%.
  3. Step 3: Compare the difference to the tolerance. 0.4% is less than 0.5%, so the measurement is within tolerance.
Answer: The measured slope of 2.6% is within tolerance because it is only 0.4% below the design value of 3.0%, which is less than the allowed 0.5% deviation. No corrective pass is required at this point.
2. Your design calls for a v-ditch 12 inches deep with 3:1 side slopes (3 feet of horizontal run for every 1 foot of vertical rise). How wide is the ditch opening at the top?
  1. Step 1: Identify the ditch geometry. The ditch is a v-shape, 12 inches (1 foot) deep, with two sides each having a 3:1 slope.
  2. Step 2: Calculate the horizontal run for each side. Each side rises 1 foot vertically over a horizontal distance of 3 × 1 = 3 feet.
  3. Step 3: Calculate total top width. Both sides contribute to the opening: 3 feet + 3 feet = 6 feet total top width.
Answer: The v-ditch opening at the top is 6 feet wide (72 inches). Use this figure when positioning the blade and confirming your ditch location relative to the shoulder stake.
3. You are making pull passes to build the crown. Your blade is set to a 30-degree angle from perpendicular. On a pass 10 feet long, how far does material travel horizontally (perpendicular to the machine's travel) as a rough geometric estimate?
  1. Step 1: Understand the relationship. When a blade is angled at 30 degrees from perpendicular to travel, the horizontal cast distance per unit of travel can be estimated using the tangent of the blade angle.
  2. Step 2: Apply the tangent. tan(30°) ≈ 0.577. For 10 feet of machine travel, estimated lateral material movement = 10 × 0.577 ≈ 5.8 feet.
  3. Step 3: Interpret the result. Over a 10-foot run, material is pushed approximately 5.8 feet sideways. Increasing blade angle increases lateral movement; decreasing it moves material less far to the side.
Answer: Material moves approximately 5.8 feet laterally per 10 feet of machine travel at a 30-degree blade angle. This estimate helps you plan blade positioning and windrow placement relative to the ditch line.
4. You check the v-ditch depth at three stations and record 11 inches, 13 inches, and 12 inches. The design depth is 12 inches and the tolerance is plus or minus 1 inch. Which stations, if any, need a correction pass?
  1. Step 1: Determine the acceptable range. Design depth ± 1 inch = 11 to 13 inches.
  2. Step 2: Check each station. Station 1: 11 inches — equals the minimum, within tolerance. Station 2: 13 inches — equals the maximum, within tolerance. Station 3: 12 inches — exactly on design, within tolerance.
  3. Step 3: Make a decision. All three readings fall within the 11–13 inch acceptable range.
Answer: No correction passes are needed. All three stations are within the one-inch tolerance. Record these measurements in your lab log as passing.

The math in this lesson3

Learners apply 3:1 side slopes to a 12-inch-deep v-ditch to find the top opening width.
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Brush up in the math halls at newSchoolWorks.com:
In class: Instructor demonstration of the crown-building sequence: first pass establishes centerline, subsequent passes pull material from edges toward center, final finish pass uses a low blade angle and light cut to smooth the crown; students observe from the cab observer seat, record the number and purpose of each pass type, and ask clarifying questions before operating. · Student field operation: each student independently grades the 150-foot section, beginning with a rough cut pass to establish rough crown, then ditch formation passes on one side to achieve the specified v-ditch dimensions (instructor-defined depth and side slopes), followed by a finish pass on the travel surface; instructor evaluates multi-pass planning, blade overlap, and machine positioning relative to the ditch line. · Documentation and debrief: students complete the final pages of their lab log, including total machine hours operated during the course, pre-op findings from each session, blade settings used for crown and ditch passes, elevation check results from Lesson 4, and a written reflection on one technique that improved and one that still needs practice; class discusses how these skills align to NCCER Heavy Equipment performance tasks.
Materials: Motor grader, 150-foot practice road section with ditch area prepared, grade stakes and lath, 50-foot tape, cross-slope level or smart level app on tablet, 10-foot straightedge, student lab logs (complete packet), NCCER Heavy Equipment Operations trainee guide
Check: Crown cross-slope must be within 0.5 percent of specified design slope at three measured points; v-ditch depth and side-slope must match plan dimensions within one inch; lab log reviewed for completeness and accuracy—all sections filled, elevation data consistent with field measurements, reflection substantive; overall field performance scored by instructor rubric at 75% or higher to pass the course.

Practice check8

Answer each question, then check it. Nothing is recorded; this is your own practice.

NCCER Heavy Equipment Operation – Motor Grader Skills
1. During the instructor demonstration, the first pass on the 150-foot road section is made along the centerline with a shallow cut. What is the primary purpose of this pass?
NCCER Heavy Equipment Operation – Quality and Measurement
2. A student's measured crown cross-slope reads 2.3% at the midpoint station. The design cross-slope is 3.0% and the allowable tolerance is 0.5%. What should the student do?
OSHA 10 – Construction Site Hazard Recognition
3. When forming the v-ditch, why must the operator keep machine tires well clear of the freshly cut ditch edge?
NCCER Heavy Equipment Operation – Motor Grader Controls
4. Which blade adjustment primarily controls how far material is cast laterally during a pull pass?
OSHA 10 – Heavy Equipment Safety Practices
5. A student must leave the motor grader cab briefly to check a grade stake measurement. According to safe operating practice, what must be done before exiting?
NCCER Heavy Equipment Operation – Performance Task Documentation
6. The lab log reflection section requires students to identify one technique that improved and one that still needs practice. What level of response meets the standard described in the lesson?
NCCCO Crane – Regulatory Compliance
7. The NCCCO crane operator certification is described in this program as OSHA-recognized. What does that recognition most directly mean for a crane operator working on a federal or OSHA-regulated construction site?
NCCER Heavy Equipment Operation – Documentation and Quality Control
8. During crown cross-slope verification, a student measures at the first station with a 10-foot straightedge and smart-level app, reads 3.1%, then records 3.0% in the lab log because '3.1 rounds to 3.' Is this acceptable lab log practice?
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