pultteja

Pultteja are a type of fastener used to join two or more components by clamping them together with a nut or via a threaded receptacle. The word pultti is Finnish for bolt, and pultteja is its plural. Bolts are chosen for assemblies that require disassembly, adjustment, or high clamping force, and they are used across industries such as construction, manufacturing, automotive, and electronics enclosures.

Bolts vary by head shape (hex, socket/cap, carriage, eye), by thread type (metric or imperial; partially threaded or fully threaded), and by length and diameter. They are made in materials such as carbon steel, stainless steel, alloy steel, and, for specialized uses, titanium or brass. Finishes and coatings—zinc plating, hot-dip galvanizing, black oxide, or chrome plating—improve corrosion resistance and lubricity.

Most pultteja are manufactured to international or regional standards. Common frameworks include ISO standards for metric bolts (for example ISO 4014/4017 for hex bolts) and ISO 898 for mechanical properties, as well as DIN or ANSI equivalents. Metric bolts use M-diameters; inch-series bolts use traditional threads such as 1/4-20. Specifying the grade (for example 8.8 or 10.9) indicates tensile strength.

Proper selection involves considering load type, environment, material compatibility, thread engagement length, and correct torque. Lubrication and cleanliness help achieve accurate tightening and prevent galling. Nuts and washers must match the bolt size and material.

Inspect bolts for corrosion, fatigue, or thread damage and replace damaged fasteners. In critical joints, use lock nuts or thread-locking compounds as appropriate. Avoid mixing dissimilar metals in corrosive environments to reduce galvanic corrosion.