Both devices turn power into linear force. A hydraulic cylinder uses pressurized fluid; a worm gear screw jack uses a motor-driven worm mesh and a trapezoidal or ball lifting screw. Anand Gears builds screw jacks in the 5 kN–350 kN catalogue band — we are not a hydraulics OEM. This note stays engineering-honest: jacks are not “always better.”
Positioning accuracy
Screw jacks move in discrete screw pitch increments driven by known motor turns (or encoder feedback if fitted). Stroke ends are cleanly limited with mechanical or electronic limit switches. Hydraulics can position accurately with good valves and feedback, but temperature, fluid compressibility, and valve dead-band make open-loop “park at a height” harder than a screw that simply stops turning.
Edge: screw jack for repeatable set heights on intermittent moves; hydraulics when servo-hydraulics already exist on the machine.
Hold without power
Trapezoidal screw jacks with suitable pitch and worm ratios are commonly self-locking — the load stays put when the motor is off, without continuous pump pressure. Hydraulic cylinders need check valves, counterbalance valves, or a locked pump circuit; any leak path shows up as slow drift.
Ball screw jacks reverse this: high efficiency means they usually need a motor brake for hold. Compare screw types in Tr vs ball.
Edge: Tr screw jack for long unpowered holds (platforms, gates, theatre machinery, press shut-height).
No oil, no leaks
Screw jacks use grease or oil in the worm housing — a sealed gearbox quantity, not a plant hydraulic network. There is no hose rack, no power unit tank, no fluid disposal cycle. Food, pharma, clean assembly, and indoor stages care about this. Hydraulics still need fluid conditioning and leak management.
Edge: screw jack in clean or spill-sensitive areas. Hydraulics remain fine where a power unit already serves many axes.
Synchronization simplicity
Multi-point lift with jacks: one motor, miter bevel gearboxes, line shafts, and couplings force equal travel. No proportional valve matching. Multi-cylinder hydraulic platforms need flow dividers, matched cylinders, or closed-loop control — workable, but more plumbing and tuning.
Edge: mechanical screw jack systems for 2/3/4-point platforms — see layouts and lifting systems.
Where hydraulics still win
- Speed — high linear velocity is easier with fluid power than with intermittent-duty worm jacks.
- Force density — very high forces in a compact cylinder envelope, especially continuous pushing under power.
- Shock absorption — fluid compliance can be useful; rigid screws transmit shock more directly (design cushions separately).
- Existing infrastructure — if the plant already has a hydraulic ring main, adding a cylinder is cheap; adding a jack train is a different project.
Side-by-side summary
| Topic | Screw jack | Hydraulic cylinder |
|---|---|---|
| Hold without power | Strong (Tr self-lock) | Needs valves / pressure |
| Leak / fluid risk | Minimal | Inherent system risk |
| Multi-point sync | Mechanical, simple | Valves or closed loop |
| Linear speed | Modest; intermittent | High available |
| Force density | Good in 5–350 kN classes | Often higher density |
| Infrastructure | Motor + shafts | Power unit + hoses |
Bottom line
Pick a screw jack when the job is position, hold, and clean multi-point lift under intermittent duty. Pick a hydraulic cylinder when the job is fast, continuous, high-force motion and the plant already lives on fluid power. Many factories use both — for different axes.
Related: Machine Screw Jacks · How to Size a Screw Jack · Contact