What is the difference between translating and rotating screw jack configurations?

In a Translating Screw (TP) configuration, the worm gear turns a nut which drives the screw up or down linearly — the screw does not rotate, making it ideal for lifting applications where the load must not spin. In a Rotating Screw (TPR) configuration, the screw itself rotates while the nut remains stationary — suited for applications where the screw can freely rotate. A Keyed Translating version adds an anti-rotation key for precise linear guidance.

What is the capacity range of AG machine screw jacks?

AG machine screw jacks are available from 5 kN (AG-SJ-05) to 350 kN (AG-SJ-350) capacity. Models include AG-SJ-05 (5 kN), AG-SJ-10 (10 kN), AG-SJ-25 (25 kN), AG-SJ-50 (50 kN), AG-SJ-100 (100 kN), AG-SJ-150 (150 kN), AG-SJ-200 (200 kN), AG-SJ-250 (250 kN), AG-SJ-300 (300 kN), and AG-SJ-350 (350 kN). Each is available with trapezoidal or ball screw types.

When should I choose a ball screw jack over a trapezoidal screw jack?

Choose ball screw jacks when you need high efficiency (up to 90% vs 35-45% for trapezoidal), frequent cycling, precise positioning, or lower input power. Choose trapezoidal screw jacks when you need self-locking capability (the load holds position without a brake), lower cost, or simpler maintenance. Ball screws require a brake mechanism to hold the load when power is off.

Can multiple screw jacks be synchronized in a system?

Yes, AG screw jacks can be configured into synchronized multi-jack systems using connecting shafts, bevel gear boxes, and a single motor drive. Common configurations include 2-point, 3-point, and 4-point synchronized lifting systems. These are used in industrial applications like platform levelling, mould adjustment in presses, and heavy equipment positioning where uniform lifting across multiple points is required.

What mounting forms are available for AG screw jacks?

AG screw jacks are available in multiple mounting forms: upright base mounting (standard), inverted mounting (screw pointing down), top-plate mounting with clevis, trunnion mounting for pivoting applications, and travelling nut configurations. Custom mounting arrangements are available for specific installation requirements.

What accessories are available for AG screw jacks?

AEI screw jack accessories include: Protective Bellows (elastic accordion-style dust/debris shields in neoprene, silicone, or heat-resistant materials), Limit Switches (mechanical and electronic stroke-limiting devices with adjustable cams), Motor Flanges & Couplings (IEC B5/B14 flanges for frame sizes 56–180), Safety Nuts (dual-nut wear monitoring system for fail-safe operation), Anti-Rotation Guides (dual-guide rail systems for lateral load absorption), and Oil Bath Lubrication Systems (sealed oil chambers for continuous-duty operation).

What special configurations of screw jacks are available?

AG offers four special screw jack configurations: (1) Corrosion Resistant — AISI 316 stainless steel with Niploy coating for marine, chemical, and water treatment applications. (2) High Temperature — Viton (FKM) seals rated to 200°C with synthetic high-temp lubricants for foundry and furnace environments. (3) Food & Pharmaceutical Grade — stainless steel with NSF H1 food-grade lubricants and washdown-rated (IP65+) design. (4) Custom Engineering — application-specific designs with custom stroke lengths, special gear ratios, and non-standard mounting forms.

What are bevel gearboxes and how do they work with screw jacks?

Bevel gearboxes provide 90-degree power redirection using Gleason-type spiral bevel gears, enabling synchronized multi-jack systems. A single motor drives multiple screw jacks through connecting shafts and bevel gearboxes. Available configurations include 2-point (L-type bevel), 3-point (T-type bevel), and 4-point (cross bevel) systems. AG offers 10 standard bevel gearbox sizes matching AG-SJ-05 to AG-SJ-350 jack models, with ratios from 1:1 up to 1:12 and options for stainless steel construction.

Machine Screw Jacks — 5 kN to 350 kN Lifting Capacity

AG machine screw jacks — translating and rotating configurations

Linear Motion

Machine Screw Jacks for Precise Linear Motion

AG machine screw jacks convert rotary motion into precise linear movement through a worm gear drive mechanism. Available in capacities from 5 kN to 350 kN, these jacks are engineered for lifting, lowering, pushing, pulling, and precise positioning across a wide range of industrial applications. Each unit combines a hardened worm shaft with a bronze worm gear for maximum durability and smooth, reliable operation.

Self-locking trapezoidal screw (holds load without brake)

Ball screw option for high-efficiency, high-speed duty

Translating, rotating, and keyed configurations

Multi-jack synchronized systems via bevel gearboxes

Cast iron & aluminium housings for strength and corrosion resistance

Protective bellows, limit switches, and encoders available

Configurations

Three Operating Configurations

Select the configuration that matches your application — translating screw, rotating screw, or keyed translating for anti-rotation requirements.

Translating Screw — Type TP

The most common configuration. The worm gear drives the screw spindle up or down in a linear path while the spindle itself does not rotate. Ideal for lifting platforms, press tables, and positioning applications where the load connects directly to the moving screw end.

Motion TypeLinear (screw translates, does not rotate)
Anti-RotationProvided by internal keyway
Load ConnectionClevis, flange, or threaded end
Best ForPlatforms, press tables, dam gates, stage lifts

Rotating Screw — Type TPR

In this configuration, the screw spindle rotates while the nut travels linearly along the screw. The load is attached to the travelling nut. This is suited for applications requiring a compact installation height, or where the screw needs to be supported at both ends for long strokes.

Motion TypeScrew rotates, nut translates linearly
Anti-RotationExternal guide required for nut
Load ConnectionVia travelling nut with mounting flange
Best ForLong strokes, dual-support installations, conveyor adjustment

Keyed Translating Screw

A translating screw with an additional external keyway machined along the screw spindle. The key engages with a mating slot in the housing cover, positively preventing screw rotation. This configuration is required when high torsional loads or external forces could otherwise cause uncontrolled screw rotation.

Motion TypeLinear (positive anti-rotation via keyway)
Anti-RotationExternal keyway on screw + key slot in cover
Load ConnectionClevis, flange, or threaded end
Best ForHigh torsion loads, solar trackers, precision tooling

Technical Data

Specifications by Model

10 models from AG-SJ-05 to AG-SJ-350 cover the full range of industrial lifting requirements. Two gear ratios per model for optimised speed vs. load performance.

Model	Capacity (kN)	Screw Dia. (mm)	Gear Ratio	Travel/Rev (mm)	Max Input Speed (rpm)	Efficiency (%)	Weight (kg)
AG-SJ-05	5	20	1/4	5	1800	35	3.5
AG-SJ-05	5	20	1/8	2.5	1800	28	3.5
AG-SJ-10	10	24	1/4	6	1800	35	5.2
AG-SJ-10	10	24	1/8	3	1800	28	5.2
AG-SJ-25	25	30	1/4	6	1800	33	8.4
AG-SJ-25	25	30	1/8	3	1800	26	8.4
AG-SJ-50	50	36	1/8	4	1500	30	14.6
AG-SJ-50	50	36	1/16	2	1500	22	14.6
AG-SJ-100	100	46	1/8	6	1200	28	28.5
AG-SJ-100	100	46	1/16	3	1200	22	28.5
AG-SJ-150	150	55	1/8	6	1000	27	42.0
AG-SJ-150	150	55	1/16	3	1000	21	42.0
AG-SJ-200	200	65	1/16	4	900	25	62.0
AG-SJ-200	200	65	1/24	2.7	900	20	62.0
AG-SJ-250	250	70	1/16	4	800	24	78.0
AG-SJ-250	250	70	1/24	2.7	800	19	78.0
AG-SJ-300	300	80	1/16	5	700	23	98.0
AG-SJ-300	300	80	1/24	3.3	700	18	98.0
AG-SJ-350	350	85	1/16	5	600	22	118.0
AG-SJ-350	350	85	1/24	3.3	600	17	118.0

Specifications are for trapezoidal screw versions. Ball screw variants offer higher efficiency (up to 90%) and faster travel speeds. Contact us for ball screw specifications.

Screw Technology

Trapezoidal vs. Ball Screw

Choose the screw type based on your duty cycle, speed, and self-locking requirements.

Parameter	Trapezoidal Screw	Ball Screw
Efficiency	25–35%	80–90%
Self-Locking	Yes — holds load without brake	No — external brake required
Positioning Accuracy	±0.1 mm	±0.02 mm
Max Linear Speed	Moderate (limited by friction heat)	High (lower friction, higher speeds)
Duty Cycle	Up to 30% ED	Up to 100% ED
Noise Level	Low	Very Low
Maintenance	Periodic lubrication	Sealed, longer intervals
Cost	Lower	Higher (precision ground)
Typical Use	Static holding, infrequent positioning	Continuous motion, high-speed cycling

Mounting Options

Mounting Configurations

Standard mounting forms for flexible integration into your machine design.

Form S — Base Mounted

Standard foot-mounted configuration. The jack housing is bolted to the base structure via machined mounting feet. The screw extends vertically upward. Most common mounting for lifting platforms, press tables, and general positioning.

Form B — Top Plate Mounted

Inverted mounting with the housing bolted to an overhead structure. The screw extends downward. Used when the jack needs to push down or when the housing must be mounted to an upper frame, gantry, or ceiling structure.

Form D — Flange Mounted

The housing is attached via a machined flange for direct coupling to machine frames or other mechanical assemblies. Provides precise axial alignment and is used when space constraints prevent foot mounting. Available in horizontal and vertical orientations.

Synchronized Systems

Multi-Jack Lifting Systems

Synchronize two, three, four, or more screw jacks with a single motor drive for perfectly level lifting and positioning.

How It Works

Multiple screw jacks are mechanically linked via bevel gearboxes and cardan shafts (connecting shafts), all driven by a single electric motor through a common worm shaft. Because every jack is mechanically coupled, all lifting points move at precisely the same speed — ensuring perfect synchronization without the need for electronic controls or feedback sensors.

Bevel Gearboxes

Right-angle power distribution — redirect the drive shaft around corners and to multiple jack positions. Available in T-type (1 input, 2 outputs) and L-type (1 input, 1 output at 90°).

Cardan Shafts

Telescopic connecting shafts with universal joints transmit torque between jacks and gearboxes. Available in standard lengths from 500 mm to 6000 mm, with custom lengths on request.

System Layouts

Standard 2-point, 3-point, 4-point, and 6-point configurations. Custom layouts for complex geometries — we design the complete drive train including motor, gearboxes, shafts, and jacks.

Applications

Where Screw Jacks Work

From heavy steel mills to precision stage machinery — screw jacks deliver reliable linear motion in the most demanding environments.

Steel & Metal Processing

Rolling mill adjustment, furnace door positioning, ladle tilting mechanisms, and continuous casting mould oscillation. High-capacity AG-SJ-200 to AG-SJ-350 models for heavy loads.

Automotive Manufacturing

Body-in-white welding fixtures, press die height adjustment, paint booth conveyor levelling, and assembly line platform positioning with synchronized 4-point systems.

Solar Tracking Systems

Single-axis and dual-axis solar panel trackers. Keyed translating screw configuration prevents wind-induced rotation. Ball screw variants for continuous daily tracking cycles.

Stage & Theatre Machinery

Precision stage lifts, orchestra pit platforms, scenery fly systems, and revolving stage mechanisms. Low-noise trapezoidal screws with synchronized multi-point lifting for perfectly level stage movement.

Press Tables & Die Setting

Adjustable-height press bolsters, die clamping systems, and platen levelling. Self-locking trapezoidal screws hold the set position without hydraulic pressure or external braking.

Dam Gates & Water Management

Sluice gate positioning, weir adjustment, and floodgate operation. Heavy-duty AG-SJ-250 to AG-SJ-350 models with corrosion-resistant coatings for wet and submerged environments.

Product Families

Screw Jack Series

Three distinct product families to match your application requirements — from self-locking static loads to high-speed precision positioning.

Standard Trapezoidal Series

Self-locking mechanical screw jacks with trapezoidal thread — the most versatile choice for lifting, pushing, pulling, and aligning loads. Holds position without a brake when power is off.

Capacity 5 kN – 350 kN

Models 10 sizes (AG-SJ-05 to AG-SJ-350)

Efficiency 25–35%

Self-Locking Yes (irreversible)

Gear Ratios 1/4, 1/8, 1/16, 1/24, 1/32

Housing Cast iron / aluminium

Ball screw jack series — high efficiency precision positioning

Ball Screw Series

High-efficiency ball screw jacks for intensive duty cycles and precision positioning. Recirculating ball nut delivers up to 90% efficiency with minimal friction and heat generation.

Capacity 5 kN – 350 kN

Efficiency 80–90%

Duty Cycle Up to 100% ED

Accuracy ±0.02 mm positioning

Self-Locking No (external brake required)

Lubrication Oil bath / sealed grease

Heavy duty screw jack series — extreme load applications

Heavy Duty Series

Engineered for extreme loads and demanding environments. Reinforced cast iron housings, hardened worm gears, and oversized screw spindles for steel mills, presses, and heavy infrastructure.

Capacity 200 kN – 350 kN

Models AG-SJ-200, AG-SJ-250, AG-SJ-300, AG-SJ-350

Screw Dia. 65 mm – 100 mm

Housing Reinforced cast iron

Applications Steel mills, presses, dams

Custom Special stroke lengths available

Accessories

Accessories & Options

Extend the capability and lifespan of your screw jack system with purpose-built accessories for protection, control, safety, and lubrication.

Protective Bellows

Elastic accordion-style bellows shield the screw spindle from dust, debris, metal chips, and moisture. Essential for foundry, mining, and outdoor installations. Available in neoprene, silicone, and heat-resistant materials.

Limit Switches

Mechanical and electronic stroke-limiting devices prevent over-travel at both ends of the screw stroke. Configurable setpoints with adjustable cams. Available with NO/NC contacts and proximity sensor options.

Motor Flanges & Couplings

IEC standard motor flanges (B5/B14) for direct motor mounting. Flexible jaw couplings and rigid couplings for connecting motors, gearboxes, and transmission shafts. Accommodates frame sizes 56 to 180.

Safety Nuts

Dual-nut safety system for wear monitoring and fail-safe operation. The primary nut carries the load while the secondary nut monitors wear — when the gap closes, it signals that the primary nut needs replacement before failure.

Anti-Rotation Guides

External linear guide systems that positively prevent screw rotation in translating configurations. Dual-guide rail design absorbs side loads and torsional forces. Required for applications with external lateral forces on the screw.

Oil Bath Lubrication Systems

Sealed oil bath lubrication for continuous-duty and high-cycle applications. The screw operates within a sealed oil chamber that provides consistent lubrication and heat dissipation. Extends service life and reduces maintenance intervals.

Special Variants

Special Configurations

Purpose-built screw jack variants for harsh environments, hygienic applications, and unique engineering challenges.

Corrosion Resistant

Stainless steel construction (AISI 316) and Niploy coating treatment for marine, chemical processing, and outdoor environments. Resists saltwater, acids, and industrial chemicals while maintaining full mechanical performance.

Material AISI 316 stainless steel

Coating Niploy / epoxy paint

Applications Marine, chemical, water treatment

High Temperature

Viton seals, high-temperature lubricants, and heat-treated materials for operation in foundries, furnace environments, and steel processing applications where ambient temperatures exceed standard ratings.

Seals Viton (FKM) rated to 200°C

Lubricants Synthetic high-temp formulation

Protection Heat-resistant bellows + epoxy coat

Food & Pharmaceutical Grade

Stainless steel construction with food-grade Niploy coating and NSF-approved lubricants. Designed for washdown environments with strict hygiene regulations in food processing, dairy, beverage, and pharmaceutical production lines.

Material AISI 316 stainless + Niploy

Lubricant Food-grade (NSF H1)

Rating Washdown-rated, IP65+

Custom Engineering

Application-specific screw jack designs built to your exact requirements. Custom stroke lengths, special gear ratios, non-standard mounting forms, and integrated motor packages. 30+ years of custom engineering experience.

Custom Strokes Any length, buckling verified

Special Ratios Non-standard gear ratios available

Lead Time 4–8 weeks for custom builds

Power Transmission

Bevel Gearboxes for Multi-Jack Systems

90° power redirection using spiral bevel gears — the critical link in synchronized multi-jack lifting and positioning systems.

Gleason Spiral Bevel Technology

Our bevel gearboxes use Gleason-type spiral bevel gears for quiet, efficient 90° power transmission. The spiral tooth profile provides gradual engagement, reducing noise and vibration while handling higher torque loads than straight-cut bevel gears. Available in 9 standard sizes to match every screw jack in our range.

Gear TypeGleason spiral bevel gears
ConfigurationsL-type (1:1), T-type (1:2), cross (1:3)
Ratios1:1, 1:2, 1:3 (up to 1:12 available)
Sizes10 sizes matching AG-SJ-05 to AG-SJ-350
HousingCast iron (stainless steel on request)
Drive OptionsElectric, hydraulic, pneumatic, manual

Synchronized System Configurations

2-Point System

Motor → L-type bevel → 2 jacks. Simple linear lifting with one motor and one gearbox. Ideal for platform tilt adjustment and press table levelling.

3-Point System

Motor → T-type bevel → 3 jacks via connecting shafts. Triangular lifting for three-legged platforms, antenna positioners, and stage lifts.

4-Point System

Motor → cross bevel → 4 jacks with intermediate shafts. Rectangular platform lifting, mould adjustment in presses, and large-format solar tracking arrays.

Industry Solutions

Application Showcase

From solar farms to opera houses — screw jacks deliver reliable linear motion across every major industry.

Solar Panel Tracking

Single-axis and dual-axis solar trackers using keyed translating screw jacks to tilt photovoltaic panels throughout the day. Ball screw variants handle continuous daily cycling with minimal maintenance. Multi-jack synchronized systems for large-format solar arrays.

Stage & Theatre Platforms

Precision stage lifts, orchestra pit elevators, and scenery positioning systems — used in world-class venues including opera houses and concert halls. Self-locking trapezoidal screws eliminate the risk of platform drop during power failure. Ultra-quiet operation essential for live performances.

Press Machines

Adjustable press bolsters, die height adjustment, and platen levelling for hydraulic and mechanical presses. Self-locking trapezoidal screws hold the set position permanently without hydraulic pressure — reducing energy consumption and eliminating drift.

Steel Mill Equipment

Rolling mill roll gap adjustment, continuous casting mould oscillation, ladle tilting, and furnace door positioning. Heavy-duty AG-SJ-300 to AG-SJ-350 models with high-temperature seals and heat-resistant bellows for operation near molten metal zones.

Packaging Lines

Format changeover systems, conveyor height adjustment, and sealing bar positioning in food and pharmaceutical packaging machinery. Food-grade stainless steel variants with NSF H1 lubricants for direct contact with packaging materials.

Platform Lifting & Levelling

Helicopter landing platforms, vehicle inspection ramps, loading dock levellers, and industrial work platforms. Synchronized 4-point and 6-point systems ensure perfectly level lifting across large platform areas with a single motor drive.

Antenna Positioning

Large satellite dish and radar antenna azimuth/elevation drives. Ball screw jacks provide smooth, precise angular positioning for telecommunications, defense radar, and radio telescope applications. Weather-sealed housings for outdoor installation.

Shipbuilding & Marine

Ship hull positioning during construction, drydock levelling systems, and marine hatch opening mechanisms. Corrosion-resistant stainless steel versions with Niploy coating for saltwater environments. Heavy-duty models for hull block positioning up to 350 kN.

Machine Screw Jacks