How to determine the fit tolerance for hydraulic cylinder

Hydrauic cylinders Hole And Shaft Basis Limits And Fits

                                                                  Dimensions and tolerances grades and limit deviations and fits for hole and shafts

XUD STEEL IMP. AND EXP. LIMITED offer hydraulic cylinder barrel (hydraulic honing pipes) and piston rod (chrome bars) and manufactures customized hydraulic cylinders according to international standards. We control dimensions and tolerance strictly according to Hydrauic cylinders manufacturing standards for Hole And Shaft Basis Limits And Fits

Hole basis limits and fits with Shaft basis limits and fits have been given as an example in the chart below. The definitions for descriptions given in the chart explained as follows. The chart below gives simple understanding of Hole Basis Limits and Shaft Basis Limits. Some of the application and some of the selected Preferred Fits for Hole and Shaft Basis system have been given followed by Fits explanations.

More Clearance
(Close to Top of The Chart)

More Interference
(Close to Bottom

of The Chart)

Clearance Fits


Hole Basis

Shaft Basis

Free Running



Loose Running



Easy Running






Close Clearance



Locational Clearance




Location-slight interference










Medium Drive Fit



Force Fit



Free Running; This type of tolerance can be usable where any special requirements for accuracy in not essential, but good for wide temperature variation, heavy journal pressures and high running speeds.

Applications:: Multiple fits of shafts of production and piston machines, parts rotating very rarely or only swinging.

Selected Preferred fits: H9/d9, D9/h9, H9/C9, H9/d10, D9/h8, H8/d9, H8/d8, D10/h9

Loose Running; Fits For wide commercial tolerances/clearances or allowances with parts on external members.

Applications: Fits of parts exposed to corrosive effects, pivots, latches, contamination with dust and thermal or mechanical deformations.

Selected Preferred fits: H11/c11, H11/a11, C11/h11, H11/c9, D11/h11, H11/d11, A11/h11

Easy Running: This is tuning fits with smaller clearances with general requirements for fit accuracy.

Applications:: Main fits of machine tools. General fits of shafts, regulator bearings, machine tool spindles, sliding rods.

Selected Preferred fits: H8/f8, H9/f8, F8/h6, F8/h7, H8/f7, H7/f7

Sliding/Running Fit; This fit does not provide freely running. This running/sliding tolerance fits with very small clearances for accurate guiding of shafts. This kind of tolerance helps the parts to move and turn freely and locate accurately.

Applications: sliding gears and clutch disks, parts of machine tools, pistons of hydraulic machines, rods sliding in bearings, grinding machine spindles, crankshaft journals.

Selected Preferred fits: H7/g6, H8/g7, G7/h6,

Close Clearance ( Spigots and Locations);This fit is for accurate location at moderate speeds and journal pressures, and running on accurate machine parts. Running fits with smaller clearances with general requirements for fit accuracy.

Applications:: General fits of shafts, machine tool spindles, main fits of machine tools, regulator bearings, sliding rods.

Selected Preferred fits: H8/f7, F8/h7, F8/h6, H9/f8, H8/f8, H7/f7

Locational Clearance: For locating stationary parts, it provides snug fit. It provides freely assemble and disassemble. This  fit helps for precise guiding and centering of parts and mounting by sliding on without use of any great force, after lubrication the parts can be turned and slid by hand.

Applications:: Roller guides. precise guiding of machines and preparations, exchangeable wheels.

Selected Preferred fits: H7/h6, H8/h7, H8/h9, H8/h8

Location- slight interference; This type of fit compromise between interference and clearance for accurate location. With this fit, the parts can be assemble or disassemble without great force using a rubber mallet.

Applications:: Clutches, demountable fits of hubs of gears and pulleys, manual wheels,  brake disks.

Selected Preferred fits: H7/k6, H8/k7, K7/h6, K8/h7,

Location/Transition: This fit for accurate location where greater interference permissible. It is fixed fits with small interferences or negligible clearances. Mounting of fits using pressing and light force.

Applications: Armatures of electric motors on shafts, gear rims, fixed plugs, driven bushings, flushed bolts.

Preferred fits: H7/n6, H8/n7, H8/p7, H7/m6, H8/m7, M8/h6, N7/h6, N8/h7,

Location/Interference; This type of fit where the assembled parts requiring rigidity and great alignment with prime accuracy of location. Press fit which can be separated, pressed fits with guaranteed interference. Assembly of the parts can be carried out using cold pressing.

Applications:: Bearing bushings, Hubs of clutch disks.

Selected Preferred fits: H7/p6, H7/r6, H8/r7, P7/h6, R7/h6

Medium Drive Fit This fit for shrink fit on light section or ordinary steel parts. Pressed fits with medium interference, assembly of parts using hot pressing, assembly using cold pressing only with use of large forces. the tightest tolerance usable for cast iron.

Applications:: Permanent coupling of gears with shafts, bearing bushings.

Preferred fits: H7/s6, H8/s7, H7/t6, H8/t7, S7/h6, T7/h6

Force Fit; This fit suitable for parts which can be highly stressed. Pressed fits with big interferences, assembly using pressing and great forces under different temperatures of the parts. This fit for shrink fits where the heavy pressing forces required are impractical.

Applications: Permanent couplings of gears with shafts, flanges.

Selected Preferred fits: H7/u6, H8/u7, H8/u8, H8/x8, U7/h6, U8/h7

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