Calculadora de Ajuste H7/n6

The ISO 286 standard regulates tolerances, deviations and fits for cylindrical and smooth parts, such as shafts and holes. Defines maximum and minimum limits so that the fit between pieces is correct according to their mechanical function.

In a clearance fit the hole is always larger than the shaft and allows movement. In an interference fit the shaft is larger than the hole and needs force, a press or temperature to assemble. In a transition fit the ranges overlap and you may end up with a small clearance or a small interference.

H7/g6 is a precision running fit. H7 defines the hole tolerance zone in the basic-hole system, and g6 defines a shaft slightly below nominal. It is used where parts must slide or rotate with little play and good accuracy.

Drilling alone is usually not enough for an H7 hole. The normal route is to drill leaving about 0.2 to 0.3 mm of stock and finish with a machine reamer or by boring, especially when good cylindricity is required.

Tight tolerances can come down to a few microns, and the thermal expansion of a freshly machined part can distort the reading. To validate a critical fit, let the part stabilise and measure with suitable instruments at controlled temperature.

To convert micrometers to millimeters you must divide by 1000. For example, 25 microns are equivalent to 0.025 mm. The calculator displays the limits in millimeters to facilitate direct reading on the plane and on the machine.