What design considerations are there when selecting spring pins?

What design considerations are there when selecting spring pins?
Some design considerations to keep in mind when selecting spring pins include finish, fittings, material, and material grade.
Finish
Spring pins are available in a variety of finishes, each with its own benefits. Common finishes include lightly oiled, phosphated, galvanized, cadmium and passivated stainless steel.
The lightly oiled surface protects the hardware from oxidation during shipping and storage. It should not be considered a permanent finish. Some common alloy steel spring pins have a light oil finish.

Phosphate coatings are made of thin crystalline layers of phosphate compounds. Phosphate coatings provide good corrosion resistance and provide a suitable base for painting. Use of seal oil over the phosphate coating provides additional protection against corrosion. Phosphate coatings are used on low alloy and high carbon steels and should not be relied upon in marine or highly corrosive environments.

Galvanized coatings have good corrosion resistance and are a common choice for protecting carbon steel fasteners from corrosion. Due to the popularity of galvanizing, it is relatively inexpensive to use compared to other plating solutions. It is also highly ductile and can withstand temperatures up to 120°. While galvanized coatings provide better corrosion protection than phosphate coatings, it should not be used in marine applications or other highly corrosive environments.

Cadmium Plating is a strong gold finish applied to high carbon steel spring pins. Cadmium plating enhances lubricity, prevents galling, and is very resistant to corrosion. Therefore, cadmium plating is the coating of choice for seawater and aerospace applications.

A passivated surface is a passivating oxide layer on stainless steel that provides additional protection from corrosive elements. While stainless steel is naturally corrosion resistant, this oxide layer provides additional protection against corrosion on the surface of stainless steel components.

furnish
Fitting refers to how the spring pin fits in the desired hole. Interference fit and clearance fit are two types of fit. An interference (friction) fit provides the highest level of alignment accuracy. However, it should not exceed a light press for securing or be confused with a press fit using a solid pin. A clearance (free) fit is ideal for ease of assembly because the pin surface contact pressure is much less than an interference fit. Loose fits are ideal when spring pins are used in hinge applications that require a loosening motion.
Material
The material from which spring pins are made is always an important consideration. Spring pins are made of alloy, carbon and stainless steel. Both carbon steel and alloy steel are commonly used economical materials. However, they have low corrosion resistance without supplemental plating or other surface treatments. Spring pins made of stainless steel have excellent corrosion resistance and require no additional plating. However, they are weaker than spring pins made of high carbon steel.