Piano Hinge Selection Guide: Length, Material, Finish & Load Capacity

The piano hinge — also called a continuous hinge — is one of the most common pieces of hardware on cases, wooden boxes, cabinets and instrument cases. It looks simple, yet get the length, material, thickness or hole pattern wrong and it either will not close properly or will not last. Here is what actually matters when selecting one.

What a piano hinge is

A piano hinge is a continuous metal hinge: a tubular pin runs through two interlocking leaves that extend along the full length, so it can be cut to virtually any size. Compared with two separate butt hinges, it spreads load along the entire edge, leaves no gap and looks neat — ideal where a whole edge opens and closes as one.

Six selection factors

1. Length: stock profiles commonly come in 1.8 m / 2 m and can be cut to size or customised. Boxes are usually measured to the edge; equipment doors to the door width. 2. Width: the leaf width determines load capacity and mounting surface — narrow for light small boxes, wider for heavier doors. 3. Thickness: under 0.6 mm is light-duty; 0.8-1.2 mm covers most cases and boxes; 1.5 mm and above suits equipment doors and heavy loads. 4. Material: carbon steel, stainless steel and brass are the main options. 5. Finish: drives appearance and corrosion resistance. 6. Hole diameter and pitch: determines mounting method and holding strength — always confirm for custom parts.

Matching material and finish

• Carbon steel + plating: low cost, adequate strength; zinc plating for general indoor use, nickel plating for a brighter, more durable look;
• Stainless steel: best corrosion resistance for outdoor, damp or food-contact applications, at higher cost;
• Brass: premium look and warm tone, common on jewellery and gift boxes, available brushed, polished or antique;
• Finishes: black coating, antique copper and bronze are popular for decorative boxes; coastal or high-humidity environments favour stainless or heavier plating.

Load capacity and installation

Capacity is not a single number — it comes from the hinge plus the mounting method. As a rule: light boxes work with 0.8 mm leaves; heavier or frequently used doors need thicker, wider leaves and more fixing points. Three common mounting methods: screws (removable, most common), rivets (very solid, good for metal cases) and welding (typical for equipment doors, watch for heat distortion). Keep load even across both leaves and tighten screws gradually after alignment.

Customisation

Liji can produce to drawings or samples: custom lengths and cuts, specified hole pitch, chosen material and colour, plus logo printing or stamping. Before ordering, confirm the environment (indoor/outdoor/humidity), opening frequency and load, the finish colour reference and annual volume — these drive material, thickness and pricing. Approve a sample before mass production to avoid rework.

Common questions

• Noise or looseness after fitting: usually a screw/hole mismatch or uneven load — check pitch and fixing points;
• Rust after a while: often plated carbon steel in a damp location — switch to stainless or upgrade the coating;
• Will not close flush: hinge thickness does not match the recess, or the two sides are not level;
• Can a piano hinge be cut?: yes, but cut the ends square with a proper tool to avoid burrs that scratch hands or hinder assembly.

Summary

Choose by scenario and load first, then material and finish, then the exact length, thickness and hole pattern. Liji has supplied case and box hardware for years and can advise and sample to your drawing, sample or application — tell us the requirement and volume, and we will propose a solution that balances appearance and cost.