Since it is a pure elemental plating and compatible with finishes applied to printed circuit traces, it is often specified when the spacer is soldered to the PC trace to prevent contamination. This plate has a tendency to destroy thread fits and to darken and oxidize with age and exposure and is not recommended as a finish on mechanical components. The method used on any style of spacer depends on the length and its ratio to the diameter of the thread tap. Excessively deep threading is costly and usually unnecessary in spacer applications. Threads are only made continuous where practical on standard spacers.
Table shows the thread depths used as a function of size in standard spacers.
Special depths can be ordered in quantity from the factory. Good mechanical practice dictates that certain end-finish techniques be used in manufacturing spacers. These are Outside Chamfering and Inside Countersinking of the hole or thread. This reduces the total area of the surface in contact with the mounting surface of the spacers, increasing the pressure at this surface. If the area is too small, fastening pressure will cause the spacer to dig in to the surface, deforming and possibly cracking it.