CW21 Certification
– Balance Staffing
Comprehensive Practice
Examination well written
by experts direct pass
2026/2027.
Harrison, Ohio | September 21–25
Table of Contents
1. (Questions 1–20)
2. (Questions 21–40)
3. (Questions 41–60)
4. (Questions 61–80)
5. (Questions 81–100)
6. (Questions 101–120)
7. (Questions 121–
140)
8. (Questions 141–
150)
,Section 1: Balance Staff Fundamentals & Identification
🟢 Which of the following best defines the primary function of the balance staff in a
mechanical watch movement?
A. To transmit power from the mainspring to the escape wheel
B. To serve as the rotational axis for the balance wheel and facilitate its oscillation
C. To regulate the amplitude of the pallet fork
D. To provide shock absorption for the entire movement
🔴🔴
The balance staff is the axle upon which the balance wheel rotates. It must
provide a precise rotational axis while allowing minimal friction and maintaining the
balance wheel's oscillatory motion. Options A, C, and D describe functions of other
components or incorrect attributions.
🟢 What is the primary distinction between a friction-fit balance staff and a riveted
balance staff?
A. Friction-fit staffs are used only in quartz movements
B. Riveted staffs cannot be removed once installed
C. Friction-fit staffs rely on interference fit, while riveted staffs are secured by
deformation of the staff's hub over the balance wheel arm
D. Riveted staffs have larger pivots than friction-fit staffs
🔴🔴
, Friction-fit staffs are held by precise interference between the staff and the
balance wheel's bore. Riveted staffs are secured by spreading the staff's rivet (hub) over
the balance wheel arm using a staking tool.
🟢 In modern chronometer-grade movements, which material is most commonly
used for balance wheels?
A. Brass
B. Steel
C. Glucydur
D. Invar
🔴🔴
Glucydur (a beryllium-copper alloy) is the standard material for modern
chronometer-grade balance wheels due to its thermal stability, hardness, and resistance
to deformation.
🟢 Which of the following is NOT a recognized method of balance staff removal?
A. Cutting off the rivet/hub on a lathe
B. Knocking out with a staking set
C. Grinding removal using a Molfre tool
D. Ultrasonic vibration separation
🔴🔴
, Ultrasonic vibration is not a recognized method for balance staff removal.
The recognized methods include lathe cutting, staking set knock-out, and Molfre tool
grinding.
🟢 What is the term for the cylindrical section of the balance staff that interfaces with
the roller table?
A. Pivot
B. Hub
C. Roller seat
D. Hairspring shoulder
🔴🔴
The roller seat (or roller table cylinder) is the precisely sized cylindrical
portion of the staff onto which the roller table is fitted. This diameter is critical and must
not crack the roller table when pressed on.
🟢 Which component of the balance staff is designed to minimize friction at the
point of rotation?
A. Rivet
B. Pivot
C. Cone
D. Shoulder
🔴🔴
– Balance Staffing
Comprehensive Practice
Examination well written
by experts direct pass
2026/2027.
Harrison, Ohio | September 21–25
Table of Contents
1. (Questions 1–20)
2. (Questions 21–40)
3. (Questions 41–60)
4. (Questions 61–80)
5. (Questions 81–100)
6. (Questions 101–120)
7. (Questions 121–
140)
8. (Questions 141–
150)
,Section 1: Balance Staff Fundamentals & Identification
🟢 Which of the following best defines the primary function of the balance staff in a
mechanical watch movement?
A. To transmit power from the mainspring to the escape wheel
B. To serve as the rotational axis for the balance wheel and facilitate its oscillation
C. To regulate the amplitude of the pallet fork
D. To provide shock absorption for the entire movement
🔴🔴
The balance staff is the axle upon which the balance wheel rotates. It must
provide a precise rotational axis while allowing minimal friction and maintaining the
balance wheel's oscillatory motion. Options A, C, and D describe functions of other
components or incorrect attributions.
🟢 What is the primary distinction between a friction-fit balance staff and a riveted
balance staff?
A. Friction-fit staffs are used only in quartz movements
B. Riveted staffs cannot be removed once installed
C. Friction-fit staffs rely on interference fit, while riveted staffs are secured by
deformation of the staff's hub over the balance wheel arm
D. Riveted staffs have larger pivots than friction-fit staffs
🔴🔴
, Friction-fit staffs are held by precise interference between the staff and the
balance wheel's bore. Riveted staffs are secured by spreading the staff's rivet (hub) over
the balance wheel arm using a staking tool.
🟢 In modern chronometer-grade movements, which material is most commonly
used for balance wheels?
A. Brass
B. Steel
C. Glucydur
D. Invar
🔴🔴
Glucydur (a beryllium-copper alloy) is the standard material for modern
chronometer-grade balance wheels due to its thermal stability, hardness, and resistance
to deformation.
🟢 Which of the following is NOT a recognized method of balance staff removal?
A. Cutting off the rivet/hub on a lathe
B. Knocking out with a staking set
C. Grinding removal using a Molfre tool
D. Ultrasonic vibration separation
🔴🔴
, Ultrasonic vibration is not a recognized method for balance staff removal.
The recognized methods include lathe cutting, staking set knock-out, and Molfre tool
grinding.
🟢 What is the term for the cylindrical section of the balance staff that interfaces with
the roller table?
A. Pivot
B. Hub
C. Roller seat
D. Hairspring shoulder
🔴🔴
The roller seat (or roller table cylinder) is the precisely sized cylindrical
portion of the staff onto which the roller table is fitted. This diameter is critical and must
not crack the roller table when pressed on.
🟢 Which component of the balance staff is designed to minimize friction at the
point of rotation?
A. Rivet
B. Pivot
C. Cone
D. Shoulder
🔴🔴
