Metallkraft, OMCN and Unicraft manual hydraulic presses are professional machines developed for assembling, removing, straightening, compressing, press-fitting and servicing mechanical components. Their robust upright frames allow high, progressive force to be applied while keeping the workpiece inside a stable and accessible working area. The machines in this category operate according to the same hydraulic principle but may differ in pressing capacity, frame dimensions, clearance between uprights, ram stroke, bed adjustment, cylinder positioning, approach speed and monitoring equipment. Selecting the correct press therefore requires an assessment of the complete working process rather than nominal pressing capacity alone.
A manual pump pressurises the hydraulic fluid and transfers force to the cylinder. The ram moves progressively towards the component, allowing the operator to control both initial contact and the effective application of the load. This gradual action is particularly valuable when installing or removing bearings, bushes, pins, shafts, hubs, pulleys, gears, couplings, silent blocks, joints and other interference-fit components. On models equipped with a pressure gauge, the operator can monitor changes in hydraulic pressure and identify an unexpected increase in resistance. The gauge reading must nevertheless be interpreted correctly because circuit pressure does not replace the calculation of effective force or the dimensional and alignment checks required for the component.
Before starting, the press bed must be adjusted to a position suitable for the dimensions of the workpiece and the available ram stroke. Excessive distance increases approach time unnecessarily, while insufficient clearance may prevent the tooling from being installed or the finished component from being removed. Bed support pins must be inserted fully and symmetrically into the intended positions. The working surfaces, supporting plates and blocks must be clean, undamaged and adequately sized to withstand the load without bending or slipping.
The component should be arranged so that the working axis coincides as closely as possible with the ram axis. Force must be applied centrally, avoiding angled or lateral loading that could tilt the workpiece, damage the cylinder or impose unintended stress on the frame. Shafts, pins and cylindrical components should be supported using V-blocks, rings, sleeves or shaped fixtures that prevent rolling. During removal operations, sufficient free space must be provided beneath the workpiece to receive the extracted component without allowing it to become trapped, fall uncontrollably or be projected from the working area.
Slotted plates and adjustable supports should carry structurally resistant areas of the component without loading thin walls, fragile edges, deformable flanges or finished surfaces. Nuts, spanners, uncertified hardened parts and improvised packing pieces must not be used as supports. Unsuitable shapes or materials can fracture or be ejected sideways under pressure. For recurring operations, purpose-made tooling should be produced using pressing pins, drifts, sleeves, counterplates, rings, V-blocks and depth stops. Each item must be rated for the expected force, guide the component correctly and protect threads, ground seats, functional surfaces and heat-treated areas.
When fitting a bearing, force must be applied to the ring involved in the interference fit. If the bearing is being mounted onto a shaft, the load is normally transferred to the inner ring; if it is being pressed into a housing, the load is applied to the outer ring. Applying force to the opposite ring transfers the load through the rolling elements and raceways, potentially creating indentations, noise, excessive clearance and premature failure. The same principle applies to bushes, seals, hubs and similar parts: the pressing tool must contact a resistant area and keep the component perpendicular to the assembly axis.
There is no universal dimensional tolerance for every press fit. The required interference depends on nominal diameter, paired materials, wall thickness, surface roughness, operating temperature, transmitted load and the possibility of future removal. ISO tolerance classes and fits must be selected according to the application and checked against the technical drawing. Before assembly, the shaft and bore should be measured using calibrated instruments, while roundness, taper, burrs and entry chamfers are inspected. Assembly lubricant may reduce friction and the risk of galling when permitted by the component specification, but it must never be used to compensate for incorrect dimensions.
The required pressing force is influenced by the amount of interference, the length of the fitted surface, materials and friction. Selection from the Metallkraft, OMCN and Unicraft ranges must therefore be based on the most demanding intended operation, with an appropriate working reserve and without routinely operating the press at its limit. Other important criteria include clearance between the uprights, maximum workpiece height, ram stroke, available bed positions and the possible lateral movement of the cylinder. A movable cylinder can improve access to large components or pressing points that are offset from the external geometry, provided that the configuration remains within the manufacturer’s operating instructions.
While force is being applied, the operator should observe the component and use smooth, controlled pump movements. A sudden rise in resistance, abnormal noise, tilting or movement of the supports requires the operation to be stopped immediately and the pressure released in a controlled manner. Increasing force to overcome misalignment can damage the workpiece, tooling and press. A correctly prepared fit should move consistently with its design conditions; unexpected resistance must be investigated by checking dimensions, geometry, cleanliness and positioning.
Manual hydraulic presses are used in mechanical workshops, toolrooms, industrial maintenance departments, automotive repair facilities, metal fabrication companies, machine-tool rebuilding operations and businesses assembling interference-fit components. Typical applications include servicing motors, gearboxes, pumps, machine spindles, transmissions, hubs, wheels, suspension components, joints and industrial machinery. With suitable tooling, these presses may also be used to straighten metal parts, fit dowel pins, compress springs, perform controlled forming operations and test components or fixtures.
Safe working requires the operator to remain outside the potential ejection path of workpieces, tools and fragments. Suitable personal protective equipment, protective screens and tooling rated for the applied load are essential. The capacity of the machine must never be exceeded, the pump handle must not be extended and fragile materials must not be used as supports. Components containing stored energy require dedicated restraint and containment systems. Before use, the frame, welds, bed pins, plates, cylinder, pump, hydraulic hose, connections and gauge should be inspected. Leakage, deformation, corrosion, cracking or loose fittings require work to be suspended.
Maintenance includes cleaning the supporting surfaces, protecting machined areas against corrosion, checking the level and condition of the hydraulic fluid, inspecting hoses and fittings and verifying smooth ram return. The hydraulic circuit must be protected against contamination, and servicing must only be performed after residual pressure has been released. Periodic maintenance preserves control sensitivity, reduces the risk of leakage and allows developing faults to be identified before they result in machine downtime or damage.
Tadaah supports the selection of a manual hydraulic press by assessing required force, component size and geometry, working stroke, operating frequency, accessibility and the tooling that must be produced. This approach allows Metallkraft, OMCN and Unicraft solutions to be compared according to real workshop requirements, helping professional users achieve greater safety, versatility and control during assembly, extraction, maintenance and straightening operations.
