EETC - Equipment & Engine Training Council Reel Technology and Setup Questions and Answers — Questions and Answers
Question 1: A technician observes a distinct 'washboard' or 'marcelling' pattern on a turf surface after mowing. This issue is most commonly caused by the relationship between the height of cut (HOC) and which other operational setting?
- Bedknife to reel contact being too tight
- An incorrect bedknife attitude
- Frequency of clip (FOC) being greater than the HOC (Correct answer)
- Front roller bearings being worn or loose
Correct answer: Frequency of clip (FOC) being greater than the HOC
Marcelling, or a washboard pattern, occurs when the distance the mower travels between successive clips (Frequency of Clip) is significantly greater than the height of cut. This creates a visible wave pattern on the turf. To fix this, the FOC must be made smaller, typically by increasing reel speed or decreasing ground speed.
Question 2: What is the primary purpose of applying an abrasive backlapping compound to a reel and bedknife assembly?
- To establish a relief angle on the reel blades
- To remove large nicks and damage from the bedknife
- To set the initial reel-to-bedknife clearance
- To hone and mate the cutting edges of the reel and bedknife (Correct answer)
Correct answer: To hone and mate the cutting edges of the reel and bedknife
Backlapping is a maintenance procedure that uses an abrasive paste to sharpen the reel and bedknife. By spinning the reel in reverse, the compound lightly hones both cutting surfaces, creating a perfectly matched, sharp edge between them. It is used for maintaining a sharp edge between grindings, not for heavy material removal or initial setup.
Question 3: A technician is performing a 'relief grind' on a cutting reel. Which of the following best describes the goal of this procedure?
- To make the reel perfectly cylindrical and concentric
- To reduce the contact area of the trailing edge of the reel blade (Correct answer)
- To apply a hardened coating to the cutting edge
- To sharpen only the bedknife by using the reel as a guide
Correct answer: To reduce the contact area of the trailing edge of the reel blade
A relief grind removes material from the back, or trailing edge, of each reel blade. This reduces the surface area (the 'land') that makes contact with the bedknife, which in turn reduces friction, lowers the horsepower required to turn the reel, and helps the unit stay on-cut longer.
Question 4: When performing a bench setting for the Height of Cut (HOC) on a reel mower, the measurement should be taken from a flat surface plate to the:
- Centerline of the front roller
- Top front edge of the bedknife (Correct answer)
- Lowest point of the reel blades
- Bottom of the rear roller
Correct answer: Top front edge of the bedknife
The Height of Cut is determined by the vertical distance between the bottom of the rollers (representing the ground plane) and the cutting edge of the bedknife. Therefore, when using a gauge on a flat surface, the measurement is taken from the surface plate to the top, front cutting edge of the bedknife.
Question 5: A technician is setting the reel-to-bedknife adjustment. After achieving a clean cut on a single sheet of paper across the full width of the reel, they notice the reel is very difficult to turn by hand and makes a heavy grinding sound. What is the most likely issue?
- The backlapping compound was not fully cleaned off.
- The reel bearings are failing.
- The reel-to-bedknife contact is too tight. (Correct answer)
- The bedknife attitude is too aggressive.
Correct answer: The reel-to-bedknife contact is too tight.
The goal is to achieve a clean cut with the lightest possible contact between the reel and bedknife. Excessive contact, even if it cuts paper, creates unnecessary friction, heat, and rapid wear on both the reel and bedknife. The reel should spin relatively freely after adjustment.
Question 6: The term 'Frequency of Clip' (FOC) is calculated using which three variables?
- Reel diameter, number of blades, and engine RPM
- Ground speed, height of cut, and reel speed (RPM)
- Reel speed (RPM), number of blades, and ground speed (Correct answer)
- Number of blades, bedknife angle, and reel diameter
Correct answer: Reel speed (RPM), number of blades, and ground speed
Frequency of Clip (FOC) is the distance the mower travels forward between each cut. It is a function of how fast the mower is moving (ground speed), how many cutting edges are on the reel (number of blades), and how fast those blades are rotating (reel RPM).
EETC - Equipment & Engine Training Council Reel Technology and Setup Questions and Answers
A technician observes a distinct 'washboard' or 'marcelling' pattern on a turf surface after mowing.
This issue is most commonly caused by the relationship between the height of cut (HOC) and which other operational setting?