Press-fitting shafts into and out of housings is an axial operation in which interference, alignment, support and force progression directly determine whether the structure remains dimensionally stable, concentric and undamaged.
Shafts can seize significantly due to interference, form-fit, deformation or corrosion, while housings are sensitive to local overloading and ovalisation. The pressing operation must therefore proceed fully linearly and reproducibly. A hydraulic workshop press is suitable when the technical boundary conditions demonstrably fall within the working area of the press.
This page describes when mounting and dismounting shafts falls within this application range – and when it does not.
When is a hydraulic workshop press suitable?
A hydraulic workshop press is suitable for press-fitting shafts into and out of housings when:
- the operation can be performed fully axially, without rotation or impact loading
- the pressing force is built up gradually and controllably
- the housing can be supported fully flat and torsionally stiff
- force introduction takes place via the correct surface of the shaft or receiving bushings
- alignment can be established exactly before force build-up
- the interference fit is predictable and falls within a controlled force band
When any of these conditions is not met, the operation falls outside the intended technical range of a workshop press.
Technical considerations
Pressing force & force build-up
The required pressing force is determined by:
- interference (Δd) between shaft and housing
- material combination (e.g., steel–aluminium or steel–cast iron)
- contact length
- surface roughness and condition of the fit
- possible deformation or corrosion
Important requirements:
- force build-up must take place step by step
- peak loading must be avoided
- increase in resistance must be followed as indication for misalignment, damage or galling
- the force curve must be monitored throughout the stroke
In interference fits, the force path is determined by both friction and circumferential compression of the housing. Small geometric deviations cause abrupt pressure peaks that can locally expand or crack the housing.
Interference, alignment & support
A stable pressing operation requires:
- exact axial alignment before the stroke begins
- full and flat support of the housing to prevent ovalisation and misaligned loading
- no lateral loading on the shaft or housing
- use of spacers, receiving bushings and pressing heads that follow the load-bearing mounting surface exactly
- exclusion of tilting moments in the first millimetres of the stroke
In the early phase of the press stroke, the fit is still fully cylindrical. A lateral deviation of a few tenths of a millimetre generates an asymmetrical force profile that can locally deform the housing.
Structural requirements for the press
A suitable hydraulic workshop press has:
- a welded steel frame with minimal lateral deflection
- linear stroke guidance with constant geometry
- pressing tools that centre exactly on the force-introduction surface
- a flat, massive working table for stable support of the housing
- sufficient mass to dampen force peaks and micro-movements
Frame flex >0.3–0.5 mm creates lateral forces that translate directly into misalignment between shaft and housing. This results in conical fits that cannot be corrected after mounting.
What is often underestimated in practice
- deformation of housings due to insufficient support
- seized shafts due to corrosion, galling or previous overloading
- force peaks caused by rapid pump operation
- minimal misalignment arising in the first millimetres of the stroke
- variation in interference due to temperature, wear or tolerance conditions
- risk of bore enlargement or ovalisation during dismounting
These factors determine whether mounting or dismounting can be performed dimensionally stable and functionally correct.
Typical operations within this application
- mounting shafts into bearing seats or housing structures
- press-fitting shafts out of transmission or drivetrain housings
- rework on machine frames and drivetrain modules
- dismounting seized shafts during maintenance
- series mounting of shaft structures in workshop environments
This list describes the nature of the operation, not which press configuration is required.
Relation to press classes (HD programme)
Classification within the HD programme is determined by:
- diameter
- interference
- housing stiffness
- contact length
- force profile
Light-duty press class (20–60 tonnes)
Suitable for:
- smaller shafts with short fits
- low to medium interference
- stiff housings that can be supported stably with ease
Medium-duty press class (80–160 tonnes)
Suitable for:
- typical shaft diameters and housings
- standard interference fits
- workshop use requiring reproducible force build-up
Heavy-duty press class (180–500 tonnes)
Suitable for:
- large shaft diameters and long fits
- high interference
- massive housings requiring maximum structural stiffness
The correct press class is determined by mounting conditions, interference and force profile – not by pressing force alone.
When is a workshop press not suitable?
A hydraulic workshop press is not suitable when:
- the housing cannot be supported fully flat and torsionally stiff
- the interference is unknown or highly variable
- corrosion or deformation makes dismounting unpredictable
- rotation, impact loading or knocking techniques are necessary
- misalignment cannot be structurally excluded
- structural damage to shaft or housing cannot be ruled out
Further navigation within the site
Based on this application, reference can be made to:
- the relevant press classes within the HD programme
- the available standard models
For applications that fall outside these boundary conditions, reference can be made to the engineering and custom-built hydraulic press trajectory, in which non-standard geometries and complex fits are assessed technically.
Request technical evaluation
When press-fitting shafts into or out of housings falls within the described technical boundary conditions, a technical evaluation can be requested to position the application within the correct press class.