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One workpiece has a hole in it while the other has a boss that fits within the hole. The boss is very slightly undersized so that it forms a slip fit. A staking punch is then used to expand the boss radially and to compress the boss axially so as to form an interference fit between the workpieces.
In metallurgy, cold forming or cold working is any metalworking process in which metal is shaped below its recrystallization temperature, usually at the ambient temperature.. Such processes are contrasted with hot working techniques like hot rolling, forging, welding, etc. [1]: p.375 The same or similar terms are used in glassmaking for the equivalents; for example cut glass is made by "cold ...
This technique is especially useful for aligning fastener holes in structural steel members, which always have multiple holes, such that when one pair of mating holes comes into alignment, the others in the set are aligned, allowing a fastener, usually a bolt, to be inserted, before the drift pin is removed.
The force exerted by the pin against the hole wall retains it in the hole, therefore a spring pin is considered a self retaining fastener. Spring pins may be used to retain a shaft as a journal in a plain bearing , as a type of key to fasten one shaft to another, or to precisely fasten flat faces of mating parts together through symmetric hole ...
While "artisan" holdfasts continue to be made as castings, or forgings, modern holdfasts are made from round mild steel bar stock using highly automated cold-working machines. Gramercy Tools makes such holdfasts from bar stock which is slightly under 3/4" (19.05mm) dia., usually 19mm for use in the now customary 3/4" bench holdfast holes.
A finishing operation, shaping, cold works the points on the tooth sides to flats. It might be considered as a side swage. This slightly reduces the tooth width but increases the operating time between "fittings". Swaging is a major advance over filing as the operation is faster, more precise and greatly extends the working life of a saw.
A drift punch is constructed as a tapered rod, with the hammer acting on the large end of the taper. The long end of a drift punch is placed into the semi-aligned bolt holes of two separate components, and then driven into the hole. As it is driven in, the taper forces the two components into alignment, allowing for easy insertion of the fastener.
Thus "fasten using FN7" refers to a fastener that is "find number" 7 in the list. FoS: feature of size: A type of physical feature on a part. An FoS is a feature that can have size associated with it, usually involving the opposition of two surfaces (e.g., the two diametrically opposite sides of a hole wall; the two opposite walls of a slot or ...