Hole Preparation for Press Fit Pins WHITE PAPER （洞准备压配合针白皮书）.pdfVIP

Hole Preparation for Press Fit Pins WHITE PAPER by Christie L. Jones Applications Engineer Spirol International Corporation Press fit pins are retained in an assembly by the frictional forces between the pin and its mating host component. These forces are a product of the coefficient of friction between the mating materials/coatings, and the interference fit between the pin and its host component. There are two general categories of press fit pins; solid pins and spring pins. Solid pins, such as ground dowels and knurled pins, are retained by deforming the host material. Springs pins retain themselves by compressing to conform to the hole. Successful installation and retention of press fit pins is greatly effected by the quality of the hole in the host component. Recommended hole sizes vary with the type of pin chosen for an assembly, which indirectly determines the hole preparation process. Generally, tighter hole tolerances require more expensive hole preparation. 1. Ground Dowels Straight Pins This paper addresses the hole preparation processes Ground dowels and straight pins are solid cylindrical pins required to successfully install and retain commonly used that normally have chamfered ends. The pins are retained press fit pins. The pins evaluated in this document are listed in the assembly by being pressed into holes that are smaller below, in order of increasing recommended hole tolerance. than the pin diameter. In most applications, the amount of interference has to be limited to keep insertion forces within