Interference Fit Vs Press Fit

Among the biggest users of press fits are manufacturers that assemble automotive medical white goods solar energy and consumer products.

Interference fit vs press fit. Hubs bearings bushings retainers h7 p6 p7 h6 driving fit medium interference which can be assembled with hot pressing or cold pressing with large forces e g. Such fits are not for parts designated to transmit frictional loads from one part to another by virtue of the tightness of fit. Use common tables to determine interference. Press fit light interference which can be assembled or disassembled with cold pressing e g.

The various parameters that can be included are maximum interference minimum interference maximum. It is the standard press fit for steel cast iron or brass to steel assemblies. Interference fit has limits of size so prescribed that interference always results when mating parts are assembled. Depending on the amount of interference parts may be joined using a tap from a hammer or pressed together using a hydraulic ram.

To assemble parts are usually pressed together using an arbor press. For ease of calculation we ll use dowel pins other press fits require exorbitant machining. An interference fit also known as a press fit or friction fit is a form of fastening between two tight fitting mating parts that produces a joint which is held together by friction after the parts are pushed together. We ve explored interference fits and all their design limitations but dowel pins have another application.

With interference fit becoming more dominant in the 4 inch 100 mm to 6 inch 150 mm diameter range. Permanent mounting of gears shafts bushes tightest possible with cast iron h7 s6 s7 h6. An interference fit also known as a press fit or friction fit is a fastening between two parts which is achieved by friction after the parts are pushed together rather than by any other means of fastening. Fit is defined as the degree of freedom of tightness between the mating parts in an assembly process it is also defined as the relationship between the hole and the shaft during the assembly is called fit in this article we are going to discuss different types of fits in a detailed way.

Above 6 inch diameter bores clearance fit hubs are almost exclusively used. Transition fits are of two kinds namely driving or press fit and shrink or force fit. Shaft p6 with hole h7 gives a true interference fit. Unlike jeans we can calculate exactly how tight the interference fit should be.

In addition designers need to need to know the exact amount of interference between the parts i e the difference in size between the inserted part and the hole and the length of the press fit. Though deviation is possible these are a good. While interference fits create tight assembly tolerances slip fits are just the opposite they can easily give you a self locating assembly making manufacturing easier when needing close alignment.