Table 1. Description of Preferred Fits
ISO SYMBOL
DESCRIPTION
Hole Basis
Shaft Basis
Loose running fit for wide commercial tolerances or allowances on external members. Free running fit not for use where accuracy is essential, but good for large temperature variations, high running speeds, or heavy journal pressures. Close Running fit for running on accurate machines and for accurate moderate speeds and journal pressures. Sliding fit not intended to run freely but to move and turn freely and locate accurately. Locational clearance fit provides snug fit for locating stationary parts but can be freely assembled and disassembled. Locational transition fit for accurate location, a compromise between clearance and Interference. Locational transition fit for more accurate location where greater interference is permissible. Locational interference fit for parts requiring rigidity and alignment with prime accuracy of location but without special bore pressure requirements. Medium drive fit for ordinary steel parts or shrink fits on light sections, the tightest fit usable with cast iron. Force fit suitable for parts which can be highly stressed or for shrink fits where the heavy pressing forces required are impractical.
H11/c11
C11/h11
D9/h9
H9/d9
↑ More Clearance
H8/f7 H7/g6 H7/h6
F8/h7
G7/h6 H7/h6
H7/k6
K7/h6
N7/h6
H7/n6
More Interference ↓
H7/p6 a
P7/h6
H7/s6
S7/h6
U7/h6
H7/u6
a Transition fit for basic sizes in range from 0 through 3 mm.
Made with FlippingBook - Share PDF online