Screw Press vs Mechanical Press
A screw press is energy-limited and tolerates die-height variation; a mechanical crank press is stroke-limited and works inside a narrower fixed die-height window. Choose mechanical for repeatable high-volume single-part runs; choose screw for frequent product changeover, job-shop work, and several different parts on one machine. Tooling and process parameters still need validation when changing press type.
Published: 5 Jul 2026 · Updated: 30 Jul 2026
At a Glance
| Criteria | Screw Press | Mechanical Crank Press |
|---|---|---|
| Force control | Energy-limited: fixed energy discharged per stroke, ram stops when energy is spent | Stroke-limited: fixed travel distance set by crank geometry, full flywheel energy released every cycle |
| Nominal force range | Roughly 160 to 4000 tonf on friction screw presses (100-635 mm screw diameter); direct-electric-drive units have reached about 4190 tonf, with newer servo-electric designs rated higher still | Roughly 100-12,000 tonnes on crank presses used in forging |
| Die overload behaviour | Self-regulating: runs out of energy before overloading the frame on a thicker blank or worn die | Needs added protection (shear pins, hydraulic cushion, electronic monitoring) against early die closure |
| Typical stroke rate | 15-40 spm | 20-120 spm |
| Deformation characteristic | Quick, sharp quasi-static blow; suits intricate die fill and deformation-rate-sensitive materials | Fast, repeatable fixed stroke; suits identical high-volume parts |
| Die height tolerance | Wide range on the same machine without retiming | Narrow, tuned window |
| TRIGA current availability | 250-ton Stanko F1734 and F1734A | Knuckle joint, hot forging and trimming presses, see current catalogue |
How Do Screw Presses Work?
Flywheel and screw
A motor spins a flywheel connected to a large screw. The screw converts rotation into a slow, powerful downward stroke of the ram.
Energy-limited, not stroke-limited
The press delivers a fixed amount of energy per stroke, not a fixed travel distance. The ram stops when the energy is spent, whatever the die height.
Self-limiting force
If the die closes early because of a thicker blank or die wear, the press runs out of energy sooner. It does not force the frame the way a crank press can.
Slower cycle, full contact
Screw presses typically run at 15-40 strokes per minute. The slide dwells briefly at the bottom, which helps metal fill fine die detail and suits strain-rate-sensitive materials.
Operator control
Screw presses (especially electric-drive types) allow direct control of impact energy per stroke. Crank presses deliver the same stroke profile every cycle by design.
How Do Mechanical (Crank) Presses Work?
Flywheel and crankshaft
A motor drives a flywheel; a clutch connects it to a crankshaft, which converts rotation into a fixed-length linear stroke.
Fixed stroke length
Stroke length is set by the crank geometry and does not change during production. Shut height is adjustable; stroke is not.
Position-dependent force
Peak tonnage occurs only near bottom dead centre. If the die closes earlier than the set shut height, the press can deliver full frame load through solid metal contact rather than absorbing it.
Speed advantage
Mechanical presses commonly run at 20-120 strokes per minute, well above typical screw press rates, which favours long runs of identical parts.
How Do Die Protection and Overload Behaviour Differ?
Screw press tolerates variation
Because force is energy-limited, an oversized blank or a die adjustment error reduces stroke rather than overloading the frame. This forgives day-to-day variation in stock.
Crank press needs separate protection
A mechanical press requires shear pins, hydraulic overload cushions or electronic monitoring to prevent frame or drive damage from a die that closes early.
Die wear consequences differ
On a screw press, die wear mainly changes final part dimension. On a crank press, die wear changes the force delivered at bottom dead centre, which can affect part quality before it becomes a safety issue.
Tooling changeover
Screw presses tolerate a wider range of die heights on the same machine without retiming. Crank presses are tuned to a narrower die height window.
What Are the Typical Applications?
Screw press applications
Closed-die forging of parts with varying flash geometry, cold and warm stamping, blanking, punching, bending, shallow drawing, coining and straightening, often on the same machine.
Crank press applications
High-volume hot forging, cold forging with knuckle joint drives, and trimming, where a fixed stroke and high stroke rate reduce cost per part.
Multi-part job shops
Screw presses are common where a shop forges or stamps a changing mix of parts and cannot dedicate a press to one die set long-term.
Not a substitute for hydraulic
Neither screw nor crank presses hold constant force through a long stroke. For deep drawing or dwell-dependent forming, a hydraulic press is the closer comparison.
Combining both
Many forging shops run screw presses alongside knuckle joint or eccentric presses, matching each job to the machine that fits its die variation and volume.
Current availability
TRIGA currently sources 250-ton Stanko F1734 and F1734A screw presses, alongside knuckle joint and hot forging presses. Contact us for the current catalogue.
Frequently Asked Questions
It is the same machine as a screw press. "Friction" describes an older drive method, using friction discs to spin the flywheel, versus a direct electric drive on modern screw presses. Both terms describe the same screw-and-flywheel working principle.
No. A hammer delivers a true impact blow with a very short contact time. A screw press has a slower, quasi-static stroke with a brief dwell at the bottom, which suits different die designs and gives more control over the final blow.
A screw press tolerates a wider range of die heights on the same machine without retiming, which suits frequent product changeover better than a mechanical press tuned to one die height window.
Physically it can occupy the same role, but cycle rate usually drops, and the control philosophy is different: energy-limited rather than stroke-limited. Tooling and process parameters need to be re-validated for the new drive type.
Sizing depends on part area, material and required die fill, not just nominal tonnage. Send your part drawing and material and we will advise on a suitable screw press or mechanical press.
Yes. TRIGA sources 250-ton Stanko F1734 and F1734A screw presses and knuckle joint, hot forging and trimming presses. See the machinery catalog for current availability.
160 to about 4000 tonf covers most friction screw presses, with screw diameters from 100 to 635 mm. Direct-electric-drive units have reached around 4190 tonf, with newer servo-electric designs rated higher still. This spans a similar overall range to mechanical crank presses used in forging, roughly 100-12,000 tonnes, so the deciding factor is usually die-fill and overload behaviour, not raw force availability.
A screw press regulates force by energy rather than travel distance, so it runs out of energy before the frame or tooling see damaging load if a blank is oversized or a die wears. A mechanical crank press delivers its full flywheel energy through a fixed stroke regardless of die condition, so it needs shear pins, hydraulic cushions or electronic monitoring to catch an early die closure.
Full range of used screw presses from Europe → · Full range of used forging presses from Europe →
Looking for a specific machine?
Send us your specifications and we will advise on availability, inspection options and delivery.