Allowed dimensional variation determines clearance, transition or interference between parts.
Tolerances define allowable variation; fits describe clearance, transition or interference between a hole and shaft (ISO H7/g6 etc.). Tight tolerances raise cost. Tolerance stack-up checks assembly.
A bearing seat on a shaft might use a k6 or p6 fit for a press fit.
Tolerances and fits control how parts assemble, so they decide whether a part slides, presses in or stays free.
Allowed dimensional variation determines clearance, transition or interference between parts.
Tolerances and fits control how parts assemble, so they decide whether a part slides, presses in or stays free.
A clearance fit leaves a gap so parts move freely. An interference fit has the shaft larger than the hole, so the parts must be pressed or heated to assemble.
Tighter tolerances need more precise machines, slower processes and more inspection, so they should be applied only where function requires them.
Typical applications include specifying a bearing housing that must slide without play, choosing a press fit between a gear and its shaft and setting the clearance between a pin and a hole in a hinge.
Study "Machine design process" first (topic 95 of 106 in Engineering Mechanics). It covers the groundwork this topic builds on.
Basic hole system. Surface roughness Ra. Statistical tolerancing.
A bearing seat on a shaft might use a k6 or p6 fit for a press fit.
The next topic is "Engineering drawings", which builds directly on this one.
It is classed as Advanced in Engineering Mechanics (topic 96 of 106). It is an advanced topic. It assumes you are comfortable with the intermediate topics in Engineering Mechanics.
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