A fly press is a mechanical screw press that uses a weighted flywheel to store and deliver rotational energy, which is converted to linear force via a screw mechanism. The operator pulls down on a handle or ball weight, spinning the flywheel and driving the ram downward with considerable force.
Fly presses are one of the oldest press machine designs still in regular use. They are valued for their simplicity, durability, and the quality of force delivery — the energy stored in the flywheel produces a controlled, progressive impact rather than a sudden shock. This makes them well suited to operations that benefit from a firm, steady press rather than a hammer blow.
In Australian workshops, fly presses are commonly found in small fabrication shops, toolmaking operations, and anywhere that requires a reliable, low-maintenance press for moderate production volumes. They require no power supply — just an operator.
The flywheel — typically a heavy cast iron disc with weighted arms — is mounted on a vertical screw. When the operator swings the handle, the flywheel spins and its rotational inertia drives the screw downward, pushing the ram into the workpiece.
The force delivered depends on the flywheel weight, the screw pitch, and the speed of the operator's stroke. Experienced operators can vary the force significantly by adjusting how hard they swing. This gives fly presses a degree of tactile feedback and control that powered presses cannot replicate.
After the stroke, the flywheel's remaining energy retracts the ram automatically. The operator then repositions the work for the next stroke.
Cutting flat shapes from sheet metal using punch and die tooling.
Creating holes, slots, and notches in sheet metal and non-ferrous materials.
Forming sheet metal into angles, channels, and simple shapes.
Pressing patterns, text, or features into metal surfaces.
Setting rivets in sheet metal and leather goods.
Pressing components in tool and die manufacturing.
Fly presses are rated by their number, which broadly corresponds to their size and force capability. A No. 1 fly press is a small bench-top machine suitable for light work; a No. 6 or larger is a substantial floor-standing machine capable of significant blanking and forming operations.
Used fly presses are widely available in Australia through machinery dealers and auction houses. Given their simple construction, a well-maintained used fly press can be an excellent value purchase. Check the screw thread for wear, inspect the flywheel for cracks, and verify the ram guides are not excessively worn.
New fly presses are still manufactured and available through industrial machinery suppliers. They are particularly popular in developing markets and with manufacturers who value simplicity and low running costs.