How is the size of a butt hinge denoted?

The size is denoted by the overall length of the hinge parallel to the pin.

What are the standard weight classifications?

Steel butt hinges are classified as Light Weight, Medium Weight, and Heavy Weight, differing primarily in sheet thickness and pin diameter.

How many screw holes are typically provided in a 100 mm hinge?

A standard 100 mm hinge typically has 6 countersunk screw holes (3 on each flap).

IS 1341

: 1992

Steel butt hinges

CurrentFrequently UsedSpecificationBIMArchitectural · Builder Hardware

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This Indian Standard lays down the requirements regarding materials, manufacture, dimensions, tolerances, and finish for mild steel butt hinges used extensively in building construction. It classifies hinges into light, medium, and heavy-weight categories to suit different load and application requirements.

Steel butt hinges

Quick Reference Values

standard hinge lengths50, 75, 100, 125, 150 mm

number of knuckles5

flap thickness 100mm medium1.8 mm

pin diameter 100mm medium4.0 mm

length tolerance upto 100mm± 0.5 mm

Practical Notes

Specify the weight category (light, medium, heavy) in BOQs along with the length, as length alone does not define the load-bearing capacity.

Mild steel hinges are susceptible to corrosion; ensure they are appropriately treated (e.g., galvanized, powder-coated, or painted) if used in exterior doors or wet areas.

Verify that the hinge pin is securely fitted and does not ride up during operation, a common defect in low-quality hardware.