POSITION OF A HAMMER HANDLE WHEN TUNING UPRIGHT PIANO (9-12)

[themaximillyan]

[themaximillyan]

The Solution: 9-12 O’Clock Position:

6.
1.Compensating Force: By placing the tuning hammer handle within the 9-12 o’clock range, the tuner begins to counteract the forces of the string, thus reducing the stress on the pinblock hole. By moving the tuning hammer closer to 12 o’clock, the tuner is, according to Max, reducing the amount of pressure on the bushing and the hole.
2.Reducing Wear: This is intended to reduce stress and prevent or minimize deformation of the pin hole.
3.Prioritizing Instrument Longevity: This approach puts the preservation of the piano’s integrity ahead of the tuner’s ergonomic comfort, acknowledging that it might be more challenging for the tuner.
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Implications of Incorrect Technique:
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1.Unintentional Damage: A tuner using the traditional 13-15 o’clock technique, without realizing it, is contributing to the deterioration of the pinblock over time.
2.Accelerated Wear: This deterioration accelerates the loss of friction, and therefore, slippage issues.
Why This is So Important:
Reframing Tuning as Force Management: This idea is not just about moving the pin and creating different pitches. This is also about managing the forces and stress that cause long-term wear and damage.
Systemic Approach: This demonstrates an understanding of the entire system, from the pin, to the wood in the pinblock, the strings, and the frame.
Challenge to Tradition: This challenges the traditional 13-15 o’clock approach by raising some legThe Materials Incompatibility and Mechanical Stresses of Tuning Pins in Piano Pinblocks
Introduction:
The long-term reliability and stability of piano tuning depend on a delicate balance of forces between the tuning pin and the pinblock. A critical understanding of this is essential for all piano technicians. The issues surrounding loose tuning pins are not solely a result of improper tuning techniques; they are also deeply rooted in the inherent material incompatibility and mechanical stresses resulting from the current construction of tuning pins and pinblocks.
Material Properties and Their Implications:
Tuning Pin Composition:
Hardened Steel: Tuning pins are typically made of hardened steel, chosen for its high tensile strength, wear resistance, and ability to maintain precise threading.
Inherent Rigidity: This material is exceptionally stiff and unyielding, having a very high modulus of elasticity.
Low Elasticity: Steel has low elasticity and is not designed to compress and adapt to its surroundings.
Pinblock Composition:
Laminated Hardwood: Pinblocks are typically made of laminated hardwoods, such as maple or beech, chosen for their dimensional stability, resistance to cracking, and moderate screw-holding capability.
Anisotropy: Wood is an anisotropic material, meaning its properties (strength, stiffness) vary dramatically depending on the direction of the grain. In pinblocks, the grain orientation is critical to withstand the compressive forces from the pins.
Variable Elasticity: Wood has a lower modulus of elasticity and higher viscoelasticity than steel. This means it will deform under stress (more than steel) and can exhibit some creep and hysteresis.
Hygroscopic Nature: Wood is hygroscopic, which means its moisture content and mechanical properties vary with changes in ambient humidity, causing it to expand and contract.
The Material Incompatibility:
Differential Expansion: The steel pin and wood pinblock expand and contract at different rates when exposed to changes in temperature and humidity. This differential expansion can weaken the pin’s grip and create stress at the pin/pinhole interface.
Hard Pin vs. Soft Wood: The hard steel pin acts like a screw cutting into the relatively softer wood, eventually leading to wear of the pinhole. The steel does not compress or bend, it will move only the softer material.
Stress Concentrations: The hard-on-soft interface creates stress concentrations around the pin and inside the pin hole, which lead to cracks and material fatigue.
Mechanical Stress and Wear Mechanisms:
Forces During Tuning:
String tension exerts considerable radial and axial force on the pin.
Traditional tuning techniques (13-15 o’clock hammer handle) exert even more lateral forces on the pin and hole, especially when moving up in pitch.
Even the seemingly simple action of turning a pin is not simple - it involves both rotational and axial force.
Pin-Pinhole Interaction:
The mismatch in material properties results in a high-stress area where the hardened steel pin meets the wood fibers.
Progressive Degradation: Over time, this interface suffers deformation of the pinhole (an elliptical shape), a loss of friction, and subsequent pin slippage.
Consequences of Material Incompatibility:
The inherent incompatibility accelerates wear on the pinblock.
The combination of differential expansion/contraction and the radial force of the tuning pin, leads to loose pins, an enlarged pin hole, and ultimately the need for repair.
Technically Sound Approach (Excluding Cardboard):
Pin Replacement: This is the preferred approach, removing worn pins and replacing them with new, slightly oversized pins that are designed for a tight fit in a worn pin hole.
Pinblock Repair/Restoration: When a pinblock is damaged beyond what oversized pins can correct, techniques such as:
Bushing: Inserting new, appropriately sized wood bushings into the pin holes to restore the original diameter and improve grip.
Pinblock Grafting The removal of severely damaged wood and replacing it with a graft.
Pinblock Replacement: Total removal and replacement of the entire pinblock.
Proper Tuning Techniques:
Implementing techniques such as Max’s 9-12 o’clock hammer handle position, to mitigate the effects of incorrect positioning.
Conclusion:
The challenges surrounding loose tuning pins are not just a matter of improper tuning techniques; they are rooted in the material incompatibility between hardened steel pins and laminated hardwood pinblocks. As a result, this creates uneven stress and eventual degradation. Understanding the mechanical and materials-related aspects of the system is crucial for developing and implementing best practices in piano maintenance and repair. Temporary measures such as cardboard shims are ineffective, and only a correct, long-term repair by professionals can solve such issues.

Max’s Argument for the 9-12 O’Clock Hammer Handle Position

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The Tuning Pin as a Screw:
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1.He emphasizes that a tuning pin, by design, is a screw. It’s not simply a peg or a nail, but a threaded fastener.
2.This means its movement is a combination of rotation and axial displacement (slight movement inward or outward as it is turned).
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The Problem with the Traditional 13-15 O’Clock Position:
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1.String Pressure: The string is anchored at the bridge at one end and around the tuning pin at the other. When tuning, turning a tuning pin from the 13-15 o’clock position downwards (raising the pitch) introduces string pressure to that same side as the pin turns, thus pushing the pin against the side of its hole. This force is also applied into the hole, which can create pressure and wear on the pin and the pinblock.
2.Right-Hand Threaded Pins: As you explained, the combination of the right-hand thread of the tuning pin and its position relative to the string, in combination with the traditional tuning position, amplifies the pressure.
3.Elongating the Hole: Over time, this constant pressure in one direction will contribute to an elliptical deformation of the pinhole, effectively making the hole larger. The slight wobble in the pin becomes larger and eventually leads to slipping issues.
4.Loss of Friction: The elliptical shape of the hole will mean the pin will lose the 1mm friction, as you mentioned, and it will eventually slip.itimate concerns about force and preservation, as you mentioned.
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