Understanding Backcheck Regulation in Upright and Grand Pianos
Lesson Overview
One of the most important yet often misunderstood aspects of Piano Regulation is proper Backcheck Adjustment. A correctly regulated backcheck allows the hammer to be caught after striking the string, helping the action reset properly and providing the pianist with greater control, repetition, and consistency. In this lesson, we explore the fundamentals of Piano Backcheck Regulation in both upright and grand pianos, including proper Backcheck Distance, the standard 5/8" Backcheck specification, and the tools used for effective adjustment. We also discuss how backchecks interact with other critical areas of Piano Action Regulation, including Let Off Regulation and Aftertouch Regulation, and examine common causes of Bobbling Hammers and Double Striking Hammers.
What Is a Backcheck?
The backcheck is responsible for catching the hammer after it rebounds from the string. When functioning correctly, the hammer is held in a controlled position, preventing excessive rebound and allowing the action to reset efficiently for the next keystroke.
If the backcheck is improperly adjusted, a piano may exhibit symptoms such as:
- Double striking
- Bobbling hammers
- Inconsistent repetition
- Loss of control during soft playing
- Excessive hammer movement after impact
Understanding the relationship between the backcheck, let-off, aftertouch, blow distance, and other regulation settings is critical for achieving optimal performance.
Tools Used for Backcheck Regulation
Several tools can make backcheck regulation faster and more accurate:
Regulation Gauge
A regulation gauge allows technicians to visually verify backcheck distance and compare it to standard regulation specifications.
Wire-Bending Pliers
Often referred to as "smiley frownies," these specialized pliers are designed to bend backcheck wires accurately without damaging surrounding components.
Straightedge
A straightedge can be used to align multiple backchecks quickly and maintain consistency across a section of the piano.
Checkering File
A checkering file is used to roughen smooth hammer tails in grand pianos, improving the grip between the hammer tail and the backcheck leather.
Standard Backcheck Specifications
The traditional specification for backcheck distance is approximately:
5/8" (16 mm)
This measurement represents the distance between the hammer and the string after the hammer has been caught by the backcheck.
While 5/8" serves as a useful starting point, many technicians make small adjustments based on the piano's design, touch, and playing characteristics.
Regulating Backchecks on Upright Pianos
When regulating upright backchecks:
- Verify that each backcheck is centered directly behind its catcher.
- Use wire-bending pliers to make side-to-side corrections if necessary.
- Check the backing distance using a regulation gauge.
- Bend the backcheck wire forward or backward to achieve the desired specification.
- Verify that all backchecks are aligned consistently throughout each section of the action.
Rather than regulating every note individually, many technicians establish sample notes throughout a section and use a straightedge to align the remaining backchecks to those references.
Regulating Backchecks on Grand Pianos
Grand piano backchecks require a slightly different approach.
Because adjustments must be made with the action removed from the piano, technicians often:
- Establish reference samples throughout the bass, tenor, and treble sections.
- Remove the action.
- Adjust backchecks to match the established samples.
- Reinstall the action and verify consistency.
- Repeat as necessary until the desired results are achieved.
Many technicians use their hand to simulate the string position while checking alignment and regulation on the bench.
Common Backcheck Problems
Double Striking or Bobbling Hammers
While improper backcheck regulation can contribute to double striking, it is often a symptom of other regulation issues, including:
- Insufficient aftertouch
- Incorrect key dip
- Improper let-off
- Incorrect blow distance
Always verify these adjustments before assuming the backcheck is solely responsible.
Worn Backcheck Felts or Catchers
Over time, the felt or leather surfaces involved in backchecking can wear significantly. When these materials deteriorate:
- The hammer may fail to catch consistently.
- Excessive noise may occur.
- Double striking may become more common.
Replacement of the worn materials may be necessary before proper regulation can be achieved.
Smooth Hammer Tails
In grand pianos, hammer tails can become polished through years of use. When this occurs, the backcheck may struggle to grip the hammer tail securely.
A checkering file can be used carefully to roughen the hammer tail surface and restore proper backcheck performance.
Practical Troubleshooting Tips
When diagnosing a backcheck problem:
- Confirm proper key dip.
- Verify let-off and aftertouch.
- Check blow distance.
- Inspect backcheck alignment.
- Examine hammer tail condition.
- Evaluate repetition spring tension.
- Look for worn felts or leather components.
Always approach troubleshooting systematically rather than assuming the backcheck itself is the sole source of the problem.
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Key Takeaways
Proper backcheck regulation is essential for achieving reliable repetition, responsive touch, and consistent hammer control. While the traditional 5/8" specification provides a useful starting point, successful regulation requires understanding the interaction between the backcheck and the rest of the action. By using the proper tools, following a systematic process, and carefully diagnosing related regulation issues, technicians can greatly improve the performance and playability of both upright and grand pianos.
Lesson Summary!
In this lesson from The Artisan School, we explore the fundamentals of Piano Backcheck Regulation for both upright and grand pianos. You'll learn proper Backcheck Adjustment techniques, understand the importance of correct Backcheck Distance, and discover how the standard 5/8 Backcheck specification affects touch, repetition, and control. We also cover the relationship between backchecks and other critical areas of Piano Regulation, including Let Off Regulation, Aftertouch Regulation, and overall Piano Action Regulation. Whether you're performing Upright Piano Regulation, Grand Piano Regulation, troubleshooting Bobbling Hammers and Double Striking Hammers, or simply learning How To Regulate A Piano, this lesson provides practical guidance used by professional technicians in the field. Perfect for students seeking Piano Technician Training, Piano Repair Training, and anyone looking to Learn Piano Repair or Becoming A Piano Technician.
