Pinthrough

Pinthrough is a fastening method where a pin is driven through aligned holes in two or more parts to secure them together and maintain their relative positioning. This approach is used in mechanical assemblies, woodworking, and metal fabrication because it provides a simple, removable connection that can be disassembled without damaging components. The term may appear as "pin through" or "pin-through" in technical documentation.

Common forms include solid pins such as dowel pins or clevis pins, and spring or roll pins that rely on interference or spring tension. The pin passes through precise hole alignments and is retained by an end cap, cotter pin, R-clip, safety pin, or by press-fit friction. In some designs, the pin is secured with a threaded fastener on one end or with a retaining ring. The choice of pin type depends on load, alignment needs, and serviceability requirements.

Typical applications include linkage pins in machinery, hinge pins in doors or lids, agricultural equipment, and furniture joinery. Advantages of pinthrough include straightforward installation, easy disassembly, and good alignment. Limitations include lower strength in shear compared to threaded fasteners, potential pin wear, risk of loosening if not secured, and the need for precise hole alignment and tolerance control. Pins must be selected for material compatibility and environmental conditions to prevent corrosion and wear.

Design considerations emphasize hole sizing, pin material, corrosion resistance, lubrication, and the method of retention. Alternatives such as through-bolts and rivets may offer higher strength or permanence but reduce serviceability. Pinthrough remains a common, versatile method for removable, well-aligned joints in a range of industries.