The grand piano is one of the most recognizable instruments on the planet. It has graced concert halls, living rooms, recording studios, and churches for centuries. And yet, for all its familiarity, most people have no idea how many individual pieces come together to make it work.
A full-sized grand piano contains thousands of components, but the exterior cabinet alone features dozens of carefully engineered parts. Each one has a specific job, whether that’s holding the lid open at the right angle, keeping the keys protected, or making sure the whole instrument rolls smoothly across a stage floor.
If you’ve ever lifted the lid of a grand piano and wondered what everything is called or why it’s there, you’re about to get the full picture. Every bracket, bolt, hinge, and pedal plays a role, and understanding those roles will change the way you look at this instrument.
Piano Parts Diagram & Details
The diagram shown here is a detailed illustration of a Grand Piano Cabinet, viewed from a slightly elevated front-left angle with the top board propped open. Every major external part is numbered and labeled, from the top board and its hinges at the very top of the instrument down to the pedals, legs, and casters at the base. The lid is shown in its raised position, exposing the interior strings and frame, while the keyboard, music rack, and side panels are all clearly visible along the front and flanks of the cabinet.
In total, 38 distinct parts are labeled in the diagram, covering everything a pianist or technician would encounter on the outside of the instrument. The numbering starts at the top board long hinge (part 1) and ends with the stretcher bar (part 38), following a roughly top-to-bottom, front-to-back sequence around the body of the piano.
What follows is a part-by-part breakdown of each labeled component. You’ll learn what it does, where it sits on the piano, and why it matters.
1. Top Board Long Hinge
The top board long hinge is the metal hinge that runs along the spine of the piano where the front and rear sections of the top board (lid) meet. It allows the front portion of the lid to fold back over the rear portion when the piano is being opened or closed. Without this hinge, the lid would be one single, unwieldy slab of wood that would be nearly impossible to manage.
Because it bears the full weight of the front lid section every time the piano is opened, the long hinge needs to be sturdy and well-attached. On high-quality pianos, this hinge is made of solid brass or heavy-gauge steel and is screwed firmly into the underside of both lid sections. Over time, if the screws loosen, the lid can wobble or sit unevenly, which is why piano technicians check this hinge during routine maintenance.
2. Music Rack
The music rack is the upright panel that holds your sheet music in place while you play. It sits just above the keys, angled slightly back so you can read your music without it slipping forward. Most music racks have a lip or ledge at the bottom edge to keep pages from sliding off.
On many grand pianos, the music rack can be adjusted to different angles or removed entirely. This is handy during performances where the pianist plays from memory and wants an unobstructed view of the strings and hammers inside the piano. Some racks are ornately carved or feature the manufacturer’s logo as a decorative element.
The material and finish of the music rack match the rest of the cabinet, whether that’s high-gloss black lacquer, satin walnut, or polished mahogany. It might seem like a simple piece, but a well-designed rack keeps your music stable even when you’re turning pages quickly in the middle of a fast passage.
3. Music Shelf Guide Rail
Sitting just behind or beneath the music rack, the music shelf guide rail is a narrow strip that helps the music shelf slide in and out smoothly. Think of it like a drawer slide for your music desk. It ensures the shelf moves on a predictable track without wobbling or jamming.
This guide rail is typically made of wood and is finished to match the interior of the cabinet. It’s a small part, easy to overlook, but anyone who has ever struggled with a sticky music shelf knows how valuable a properly functioning guide rail can be.
4. Music Shelf
The music shelf is the flat, horizontal surface that supports the music rack from below. It slides forward and backward along the guide rail, allowing you to position your sheet music closer to or farther from your eyes. When pushed all the way back, it tucks neatly into the body of the piano and sits flush with the cabinet.
Pulling the shelf forward gives you a stable platform for heavier music books or multiple sheets. Some pianists use this shelf to hold pencils, metronomes, or small accessories during practice sessions. It’s a practical, everyday feature that gets used constantly but rarely gets any credit.
5. Fallboard
The fallboard is the hinged cover that folds down over the keyboard when the piano is not in use. It protects the keys from dust, accidental spills, and curious fingers. When you sit down to play, you simply lift the fallboard up and slide it back, tucking it underneath the music shelf area.
On older pianos, the fallboard drops straight down and rests against the key slip. Modern grand pianos often feature a “slow-close” mechanism that lets the fallboard descend gently, preventing it from slamming shut on a player’s fingers. This is a particularly important safety feature in homes with young children.
Beyond protection, the fallboard contributes to the piano’s visual appeal. It provides a clean, unbroken surface when closed, giving the front of the piano a polished and tidy look.
6. Side Arm
The side arm refers to the curved wooden panel that forms the left or right sidewall of the piano’s cabinet. It connects the straight section near the keyboard to the curved body of the instrument, following the contour of the piano’s rim. This piece is both structural and decorative, contributing to the overall strength of the cabinet while displaying the wood grain and finish.
Because the side arm is one of the most visible parts of a grand piano, manufacturers pay close attention to its finish. A scratch or blemish here is immediately noticeable. Professional piano movers take special care to protect the side arms during transport, often wrapping them in padded blankets.
7. Key Block
Positioned at either end of the keyboard, the key blocks are the two wooden pieces that frame the keys on the left and right sides. They keep the keyboard assembly secure and prevent the keys from shifting laterally during play. Each key block sits snugly against the edge of the key bed and the inner rim of the cabinet.
Key blocks are removable, which is essential for piano technicians. When a technician needs to access the action mechanism underneath the keys for regulation, voicing, or repair, they first remove the key blocks and then lift the entire keyboard and action assembly out of the piano. They’re held in place by wing bolts, making removal quick and tool-free.
8. Logo
The logo is the manufacturer’s brand name or emblem, usually displayed prominently on the front of the cabinet above the fallboard or on the cast-iron plate inside the piano. On the outside, it’s often rendered in gold lettering or inlaid into the wood. Famous names like Steinway, Yamaha, Bosendorfer, and Kawai all have distinctive logos that carry significant prestige.
For collectors and buyers, the logo is one of the first things they look for because it instantly communicates the piano’s lineage, quality tier, and approximate value. A well-preserved logo on a vintage piano can actually affect resale price.
9. Keys
The keys are the most interactive part of the piano and the primary interface between the player and the instrument. A standard piano keyboard has 88 keys, consisting of 52 white keys and 36 black keys. Each key is a lever that, when pressed, triggers a hammer to strike a corresponding string or set of strings inside the piano.
White keys were traditionally made with ivory tops, but modern pianos use high-quality plastic or synthetic materials that mimic the feel and texture of ivory. Black keys, once made of ebony, are now typically made from molded plastic or composite materials. The surface texture matters a great deal to players because it affects grip, especially during fast passages or when hands get slightly damp.
What most people don’t realize is how precisely each key must be weighted and leveled. Piano technicians spend hours adjusting the “touch weight” of individual keys so that the keyboard feels even from the lowest bass note to the highest treble. An uneven keyboard is immediately noticeable to a trained pianist and can make a piano feel unreliable.
10. Key Slip
The key slip is the long, narrow strip of wood that runs along the front edge of the keyboard, just below the keys. It sits between the keys and the player’s lap, acting as a finished border that conceals the front edge of the key bed. It also prevents small objects from falling into the gap beneath the keys.
This part is removable on most grand pianos. Technicians take it off along with the key blocks when they need to service the keyboard or action. Despite its simple appearance, a warped or poorly fitting key slip can interfere with the lowest keys at the bass end of the keyboard.
11. Key Bed
The key bed is the flat, sturdy wooden platform that the entire keyboard and action assembly rests on. It spans the full width of the piano and must be perfectly level. Any warping, sagging, or unevenness in the key bed will affect how the keys sit and how evenly the piano responds to touch.
Because the key bed supports so much mechanical activity, it’s built from strong, stable hardwood. In humid or fluctuating climates, the key bed can expand or contract slightly, which is why climate control is so important for pianos. A dehumidifier inside the piano or consistent room humidity can prevent key bed issues.
12. Leg (Bass #1)
This is the front-left leg of the grand piano, positioned on the bass side of the instrument. It bears a significant portion of the piano’s total weight, which can range from 500 to over 1,200 pounds depending on the model. The leg is attached to the underside of the cabinet using a heavy-duty leg bolt and typically features a turned or tapered design that matches the piano’s style.
Grand piano legs are engineered to be removable for transport. Movers detach all three legs, lay the piano on its side, and wrap it carefully before loading it onto a truck. Despite their solid appearance, piano legs can crack or split if the piano is bumped or moved carelessly, making professional moving a must.
13. Lyre Post
The lyre post is the vertical wooden support that connects the lyre (the pedal assembly housing) to the underside of the piano. It keeps the lyre stable and properly aligned with the pedal rods that run up into the piano’s action. Without the lyre post, the pedals would wobble and feel unstable under your foot.
This post is secured with bolts and brackets and needs to be tight for the pedals to function correctly. A loose lyre post is one of the more common issues found during piano inspections, and it can cause the pedals to feel spongy or unresponsive.
On taller grand pianos, the lyre post is longer, while baby grands use a shorter version. Either way, it’s a critical structural link between your feet and the instrument’s internal mechanisms.
14. Soft Pedal
Located on the far left, the soft pedal (often called the una corda pedal) shifts the entire keyboard and hammer assembly slightly to the right. This means each hammer strikes fewer strings than usual, producing a softer, more muted tone. The name “una corda” is Italian for “one string,” reflecting the original design where the shift caused hammers to hit only one string instead of the usual two or three.
Pianists use the soft pedal for passages that call for a delicate, intimate sound. It’s not about reducing volume alone but about changing the tone color. The resulting sound is warmer and slightly veiled, which can be incredibly expressive in slow, lyrical pieces.
15. Sostenuto Pedal
The middle pedal on a grand piano is the sostenuto pedal. It’s the least understood of the three pedals, but it’s extremely useful. When you press and hold certain keys, then press the sostenuto pedal, only those specific notes will sustain while every other note you play afterward will behave normally, damping as soon as you release the key.
This selective sustain is a powerful tool for advanced repertoire. Composers like Debussy and Ravel wrote passages that are virtually impossible to perform correctly without the sostenuto pedal. It lets you hold a bass note or chord ringing while your hands move freely across the rest of the keyboard.
Not all pianos have a functioning sostenuto pedal. On some uprights and lower-end grands, the middle pedal may serve a different purpose, such as a practice mute. But on a quality grand, this pedal is the real deal.
16. Sustaining Pedal
The rightmost pedal is the sustaining pedal, and it’s the one pianists use most. Pressing it lifts all the dampers off the strings at once, allowing every note you play to ring out and blend together until you release the pedal. It’s what gives the piano its rich, resonant, “singing” quality.
Learning to use the sustaining pedal well is one of the most important skills for any pianist. Overuse creates a muddy, blurred sound where notes bleed into each other. Skilled players develop a technique called “half-pedaling,” where they depress the pedal only partway to control exactly how much sustain they want.
17. Pedal Box
The pedal box, sometimes called the lyre or pedal lyre, is the housing that holds all three pedals. It’s a carved or molded wooden frame that sits beneath the piano, connected to the underside of the cabinet by the lyre post and lyre brace. The pedal box gives the pedals a solid, stable base to pivot from.
Inside the pedal box, each pedal is mounted on a pivot rod that allows it to swing up and down smoothly. Springs return each pedal to its resting position when you lift your foot. The box itself is finished to match the piano’s exterior and often features decorative curves or molding.
18. Leg (Treble #2)
This is the front-right leg, positioned on the treble side of the keyboard. Like its counterpart on the bass side, it supports a large share of the piano’s weight. Together with the bass leg and the rear leg, it forms a stable three-point base that distributes the instrument’s considerable mass evenly across the floor.
The treble leg is identical in design to the bass leg and is attached in the same way, with a leg bolt threaded into a metal plate embedded in the piano’s underside. On some models, the leg design is a signature style element, with fluted columns, square tapers, or ornate carved details.
19. Pedal Rod
Pedal rods are the metal or wooden dowels that transmit the motion of each pedal upward into the piano’s internal mechanism. When you press a pedal, the rod pushes or pulls a lever inside the piano that activates the corresponding function, whether that’s lifting dampers, shifting the action, or engaging the sostenuto mechanism.
These rods run vertically from the pedal box through the lyre post and into the underside of the key bed. They need to be straight and properly adjusted for the pedals to feel responsive. A bent or misaligned pedal rod will make the pedal feel stiff, sluggish, or uneven.
Over time, the felt bushings that cushion the pedal rods can wear down, introducing rattles or clicks when you press the pedal. Replacing these bushings is a straightforward repair that makes a noticeable difference in how the pedals feel and sound.
20. Lyre Brace
The lyre brace is a horizontal support bar that connects the bottom of the lyre to the piano’s cabinet or to the legs. It adds lateral stability to the pedal assembly, preventing it from swaying side to side when the pedals are pressed with force. Without the brace, the entire lyre would flex and eventually loosen.
On some grand pianos, the lyre brace runs from the pedal box to one of the front legs. On others, it connects directly to the underside of the piano. Either way, the brace must be firmly attached. A loose lyre brace is a common culprit behind rattling or buzzing sounds that seem to come from the bottom of the piano.
21. Leg Bolt
Each of the three legs is secured to the piano by a leg bolt, which is a heavy-duty threaded bolt that screws through a metal plate on the piano’s underside and into a receiving nut embedded in the top of the leg. This system allows the legs to be removed and reattached without tools beyond a simple wrench.
Leg bolts must be checked periodically. A loose leg bolt is a serious safety hazard because a grand piano weighing hundreds of pounds could shift or collapse if a leg gives way. Technicians typically snug these bolts during annual tuning visits.
22. Music Rack Prop
The music rack prop is a small support arm, usually hinged, that holds the music rack at its proper angle. When you fold the music rack down (for transport or storage), the prop tucks away flat. When the rack is up, the prop swings out to brace it.
This part is easy to miss because it hides behind the music rack itself. But if it breaks or bends, your music rack won’t stay upright, and your sheet music will constantly slide down toward the keys.
23. Caster
Casters are the small wheels mounted underneath each leg. They allow the piano to be rolled short distances across a floor without lifting it. Each caster typically has a brass or steel wheel set into a cup-shaped housing that fits over the bottom of the leg.
While casters make repositioning easier, they’re designed for minor adjustments on flat surfaces, not for moving a piano across a room or between rooms. For anything more than a few inches, professional movers and a piano dolly are the way to go. On hardwood floors, many owners place caster cups under the wheels to prevent the piano from rolling on its own and to distribute weight more evenly.
24. Leg (Rear #3)
The rear leg is the single leg located at the back of the piano, near the tail end of the curved body. It supports the heavy end of the instrument where the longest bass strings and the cast-iron plate concentrate much of the piano’s weight. Because of this load, the rear leg and its attachment point need to be exceptionally strong.
During transport, the rear leg is usually the first one removed when laying the piano on its side. It’s also the one that bears the most stress during everyday use, especially if the piano sits on an uneven floor. Checking the rear leg bolt regularly is a smart habit.
25. Leg Base
The leg base is the wider, flared bottom section of each leg where it meets the caster. It provides a broader surface area to distribute weight and gives the leg a finished, grounded appearance. On pianos with turned or tapered legs, the base often has a decorative profile that complements the leg’s overall shape.
A cracked or damaged leg base can compromise the entire leg’s ability to support weight. Repairs usually involve gluing, clamping, and sometimes reinforcing with a hidden dowel or metal bracket.
26. Top Board Prop (Short)
The short prop stick is one of two support sticks used to hold the top board (lid) open. When inserted into the prop cup on the lid and resting on the rim of the piano, the short stick holds the lid at a lower, partially open position. This is called half-stick position and produces a more contained, quieter sound projection.
Pianists and sound engineers choose between the short and long prop based on the performance setting. In a small room or during a chamber music rehearsal, half-stick keeps the volume in check. It’s also the preferred position for accompanying singers or other instrumentalists who need to be heard over the piano.
27. Top Board Butt Hinge
This hinge connects the rear section of the top board to the piano’s rim along the spine. It’s what allows the rear lid section to pivot upward when you open the piano. The butt hinge is typically a heavy-duty brass or steel hinge that’s recessed into the wood so it sits flush.
Because it bears the full weight of the rear lid section every time the piano is opened, this hinge is built to last. Even so, decades of use can cause wear, and a squeaky or stiff butt hinge is a signal that it’s time for lubrication or replacement.
28. Top Board Prop (Long)
The long prop stick holds the top board open at its maximum height, known as full-stick position. This is the classic concert grand look, with the lid raised high, projecting sound outward and upward into the performance hall. Full-stick position delivers the most volume and the brightest, most open tonal quality.
Concert pianists almost always perform with the lid on full stick. The raised lid acts like a reflector, directing sound waves from the strings and soundboard out toward the audience. If you’ve ever attended a piano recital and felt the sound wash over you, the long prop stick and that wide-open lid are a big part of why.
29. Top Board Rubber Tack
The rubber tack is a small rubber bumper attached to the underside of the top board. It prevents the lid from scratching or dinging the piano’s rim when the lid is closed. It’s a tiny, inexpensive component, but without it, every time you close the lid, wood meets wood with nothing to cushion the contact.
These tacks can dry out, crack, or fall off over time. Replacing them is one of the simplest and cheapest maintenance tasks you can do, and it protects the finish from unnecessary wear.
30. Top Board (Rear)
The rear section of the top board is the larger of the two lid pieces. It spans from the butt hinge at the spine of the piano all the way to the tail. When the piano is open, this is the piece that’s propped up by the prop stick, and its broad, curved surface acts as a sound reflector.
The underside of the rear top board is usually finished in the same high-gloss or satin sheen as the outside. This matters because the audience can see it during a performance. Any scratches, water marks, or cloudy patches on the underside are clearly visible under stage lighting.
31. Top Bar
The top bar is a structural crosspiece that runs along the front edge of the piano’s rim, near the keyboard end. It provides reinforcement to the open end of the cabinet where the keys are accessed. The top bar helps the rim maintain its shape and prevents the front of the piano from flexing under the tension of the strings.
This bar is usually visible as a narrow wooden rail running across the top of the piano’s body just behind the music shelf area. It’s a load-bearing structural member, so any cracks or separations here require professional attention.
32. Top Board Prop Cup
The prop cup is a small, recessed metal or wooden receptacle mounted on the underside of the rear top board. It’s the socket that the top end of the prop stick sits in when the lid is open. The cup keeps the prop stick from sliding out of position, ensuring the lid stays safely propped.
Prop cups come in pairs on most grand pianos, one for the short stick and one for the long stick. They’re positioned at specific points on the lid to achieve the correct opening angles. A worn or damaged prop cup can cause the stick to slip, which is a serious hazard since a falling lid weighs enough to cause injury.
33. Top Board (Front)
The front section of the top board is the smaller lid piece that folds back over the rear section when the piano is fully open. When the piano is closed, this piece lies flat on top, covering the front half of the interior. It’s connected to the rear section by the top board long hinge.
During performance, the front top board is typically folded back and rests on top of the rear section. This gets it out of the way and allows the rear section to be propped up cleanly. Some pianists remove the front section entirely for concerts to save weight and simplify the stage setup.
34. Brass Lid Catch
The brass lid catch is a small locking mechanism that holds the front top board closed against the rear section when the lid is down. It prevents the lid from opening unexpectedly during transport or from vibrations during play. The catch is made of brass for durability and corrosion resistance.
Engaging the catch is a simple press-and-click action. Disengaging it usually requires a firm push or a twist, depending on the design. It’s one of those parts you use every single time you open or close the piano but never really think about until it stops working.
35. Lid Lock Bar
The lid lock bar is a metal rod or bracket that secures the top board in its closed position. It works alongside the brass lid catch to keep the lid shut firmly. On some pianos, the lock bar slides into a receiving slot on the rim, adding an extra layer of security.
This part is especially important during transport. A lid that pops open while the piano is being moved on a dolly or carried down a staircase can be dangerous and can damage the instrument. The lock bar makes sure that doesn’t happen.
36. Key Block Wing Bolt
These are the bolts that hold the key blocks in place on either side of the keyboard. They’re called “wing bolts” because they have flat, wing-shaped handles that you can turn by hand without any tools. This design allows technicians to remove the key blocks quickly for access to the action.
Wing bolts are functional, not decorative, but they’re positioned where your eyes naturally land when you sit down at the piano. On finer instruments, they’re polished brass and sit flush against the key block for a clean look.
37. Stretcher Bar
The stretcher bar is a horizontal brace that connects the front legs to each other or to the lyre assembly beneath the piano. It adds rigidity to the base of the instrument and prevents the front legs from spreading apart under the weight of the piano.
Missing or broken stretcher bars can lead to serious structural problems. Without this brace, the front legs gradually splay outward over months or years, stressing the attachment points and risking a catastrophic failure. If you ever notice the front of your piano seeming slightly wider than it should be, the stretcher bar is the first thing to check.
38. Stretcher Bar
In some diagrams and piano models, the term “stretcher bar” appears twice because there are multiple bracing bars in the lower framework. This second stretcher bar may connect the rear leg to the lyre assembly or run between different structural points under the piano.
Its function is the same as the first: to add rigidity and prevent the legs and lyre from shifting. Think of it as a second crossbeam in a table frame. The more bracing you have, the more stable the entire structure becomes, and with an instrument that weighs as much as a grand piano, stability is everything.
