Limits & Fits Reference Table

Large clearance for wide temperature variations, heavy loads, or dirty environments. Example: agricultural machinery, textile equipment.

Large running clearance. Not for high precision. Example: general machinery where temperature and load vary significantly.

Moderate running clearance with good accuracy. Example: electric motors, pumps, gearboxes, compressors.

Very small clearance for precise sliding without rotation. Example: valve spools, machine tool slides, guiding bushes.

Zero to very small clearance. Freely assembled and disassembled. Example: locating pins, dowel pins, plug gauges.

Slight interference or clearance. Accurate location with possible disassembly. Example: gears on shafts, couplings, pulleys.

More interference than H7/k6. Accurate location, disassembly requires force. Example: bearing inner races on shafts.

Light press fit. For parts requiring precise alignment without heavy loads. Example: bearing bushes, locating plugs.

Medium press fit. Requires heating of hole or cooling of shaft. Semi-permanent assembly. Example: gear wheels, bearing races.

Heavy press fit. Permanent assembly — disassembly may damage parts. Example: turbine wheels, heavy-duty couplings, locomotive wheels.

Used for high-precision measuring tools, gauges, and very accurate machine parts. Equivalent to grades for precision grinding.

Most common grade for machine parts. Used for bearings, gears, and fits requiring good accuracy. H7/h6 fit uses IT7 hole + IT6 shaft.

Standard hole basis grade. Used for general machine fits, bearing housings, and mating parts with moderate accuracy requirements.

Used for free-running fits and less critical mating parts. Suitable for agricultural and general engineering applications.

Rougher tolerance for non-critical dimensions. Used for structural parts, housings, and components where fit is not critical.

Used for loose fits, stamped parts, and rough machined components. Common in sheet metal and structural fabrication.

Wide tolerance for rough fits. Used with H11/c11 loose running fit. Common in castings and rough-machined parts.

Upper deviation below zero line by large amount. Creates very loose clearance fits with H holes. Rarely used for precision.

Upper deviation below zero. Used for loose running fits (H11/c11). Suitable for dirty environments and thermal expansion.

Upper deviation below zero. Used for free running fits (H9/d9). Good for general machinery with moderate speed.

Upper deviation below zero. Used for running fits (H8/e8). Common in bearings and rotating assemblies.

Upper deviation below zero. Used for close running fits (H8/f7). Standard for electric motor bearings.

Upper deviation slightly below zero. Used for sliding fits (H8/g7). Precise sliding without rotation.

Upper deviation at zero line. The reference shaft for hole-basis system. Creates clearance or transition fits depending on IT grade.

Deviations straddle the zero line symmetrically (js) or slightly positive (j). Creates transition fits with H holes.

Lower deviation slightly above zero. Creates transition fit with H7 (H7/k6). Accurate location, removable.

Lower deviation above zero. Creates transition to light interference fits. More accurate location than k.

Lower deviation above zero. Creates light interference fit with H7 (H7/p6). Press fit for bushes and bearings.

Lower deviation above zero. Medium interference. Used for permanent assemblies with moderate torque transmission.

Lower deviation above zero. Creates medium drive fit (H7/s6). Requires thermal assembly. Semi-permanent.

Lower deviation well above zero. Heavy interference. Permanent assembly — disassembly risks damage. Used for wheels and heavy couplings.

Very large interference. Used for extremely permanent assemblies. Assembly by heating hole or cooling shaft with liquid nitrogen.

Lower deviation at zero line. The reference hole for hole-basis fits. Most common system — reamer/hole tolerance is harder to change than shaft.

Lower deviation slightly above zero. Creates sliding fit with h shaft (G7/h6). Used for precise sliding.

Lower deviation above zero. Creates close running fit with h shaft (F8/h7). Alternative to H8/f7 for shaft-basis system.

Lower deviation above zero. Creates free running fits. Used in shaft-basis system for general machinery.

Deviations straddle zero. Creates transition fit with h6 shaft (K7/h6). Equivalent to H7/k6 in hole-basis.

Upper deviation below zero. Creates transition to interference fit with h6 shaft (N7/h6).

Upper deviation below zero. Creates interference fit with h6 shaft (P7/h6). Equivalent to H7/p6 in hole-basis.