Skip to main content
Find a contact

Acme Screw Jack

Screw Jacks

Machine (Acme) screw jacks offer positive mechanical action, precise positioning, and uniform lifting speeds. With both standard and custom engineered machine screw actuators.

Free Application Analysis
Machine Screw Actuator Product Sheet Mechanical Actuators (Screw Jacks) FAQs Rotating Machine Screw OandM Manual Translating Machine Screw OandM Manual Machine (Acme) Screw Jacks Repair Kits

Features & Benefits
  • Flexibility and Customization
    Acme screw actuators are available in various configurations, including different motor types (AC or DC) and mounting options, allowing for customization to fit specific needs and environments. Standard configurations include upright or inverted units with translating or rotating lifting screws, and top plate, threaded, or clevis ends.
  • Precise Positioning
    Controlled accurately for positioning within thousandths of one inch
  • Simplified Design and Integration
    Compared to hydraulic systems, electric linear actuators, including Acme screw types, have a simpler design with fewer components like pumps and hoses, making them easier to install and integrate with other systems.
  • Self Locking
    Models featuring higher gear ratios are inherently load holding as long as the actuator is not subject to vibration
  • Uniform Lifting Speeds
    Since many actuators feature the same gear ratios different capacities can be used in the same application to lift unevenly distributed loads with uniform speeds
  • Operational Safety
    Acme lead screws can sustain static loads, making them a safe choice for applications that require holding a position even when unpowered.
  • Quick, Sure Operation
    All actuators are designed and built to be positive acting, for accurate response to motive power
  • Quiet Operation
    When using polymer nuts, Acme screws operate with very low noise levels, making them suitable for environments where sound reduction is important, such as in healthcare or office settings.
  • Lower Maintenance Costs
    The simpler design and reduced risk of leaks (compared to hydraulic systems) lead to lower maintenance requirements and associated costs.

Specifications

Performance Specifications
Performance Table Instructions 
When reviewing and Duff-Norton Actuator Performance Specification Table, as part of the process of selecting the best-suited actuator for your application, there are several important worm-gear ratios to consider.
Standard Ratio - is frequently chosen when higher speeds and efficiency ratings are desired.
Optional Ratio - is frequently chosen when the application requires higher lifting capacities, lower speeds, or to ease the use of a handwheel.
Numeric Ratio - is frequently chosen for applications requiring fine adjustments, higher lifting capacities, lowerspeeds, the easy use of a handwheel, self locking applications, and also offers the benefit of an even number of worm input turns per inch of stroke.

Performance Specifications - Machine Screw Actuator Stainless Steel
Capacity (tons) - 17-4PH Worn 2 5 10 15 20 25 30 35 50 100
Capacity (tons) - 316 SSWorn 0.67 1.66 3.33 5.00 6.66 8.33 9.9 11.66 16.66 33.33
 
Lifting Screw Diameter (in) 1 1-1/2 2 1-1/4 2-1/2 3 3 3-3/4 4-1/2 6
  Pitch (Std. & Opt.) 0.250 0.375 0.500 0.500 0.500 0.666 0.666 0.666 0.666 0.750
  Pitch (Numerical) — 0.250 0.250 0.250 0.250 0.320 0.320 0.320 0.320 —
  Type ACME ACME ACME ACME ACME ACME ACME ACME Mod.Sq. Mod. Sq.
 
Worm Gear Ratios Standard 6:1 6:1 8:1 8:1 8:1 10-2/3:1 10-2/3:1 10-2/3:1 10-2/3:1 12:1
  Optional No. 1 24:1 24:1 24:1 24:1 24:1 32:1 32:1 32:1 32:1 36:1
  Optional No. 2 12:1 12:1 — — — — — — — —
  Numeric Ratio 25:1 25:1 25:1 25:1 25:1 32:1 32:1 32:1 32:1 —
 
Turns of Worm for 1 inch Stroke Standard 24 16 16 16 16 16 16 16 16 16
  Optional No. 1 100 67 50 50 50 48 48 48 48 48
  Optional No. 2 50 33 — — — — — — — —
  Numeric Ratio 100 100 100 100 100 100 100 100 100 100
 
Worm Torque at No Load (in-lb) Standard 5 10 20 20 30 40 40 50 100 200
Optional No. 1 5 10 20 20 30 40 40 50 100 200
Optional No. 2 5 10 — — — — — — — —
Numeric Ratio 5 10 20 20 30 40 40 50 100 200
 
Maximum Horsepower per Actuator Standard 2 4 5 5 5 8 8 8 15 25
Optional No. 1 1/2 3/4 1-1/2 1-1/2 1-1/2 1-1/2 1-1/2 1-1/2 6 11
Optional No. 2 3/4 2 — — — — — — — —
Numeric Ratio 1/2 3/4 1-1/2 1-1/2 1-1/2 1-1/2 1-1/2 1-1/2 6 11
 
Worm Torque at Full Load* (in-lb) 17-4PH Worm Standard 120 450 750 1430 2050 2700 2640 4000 7500 16000
Optional No. 1 50 185 400 820 1170 1700 1685 2400 4200 8600
Optional No. 2 75 275 — — — — — — — —
Numeric Ratio 48 175 370 640 925 1500 1800 2411 4040 —
 
Worm Torque at Full Load* (in-lb) 316SS Worm Standard 42 150 253 471 675 926 940 1366 2566 5466
Optional No. 1 19 66 141 276 394 593 600 833 1466 3000
Optional No. 2 27 95 — — — — — — — —
Numeric Ratio 25 57 67 109 144 336 635 350 619 —
 
Efficiency Rating (%) - 17-4PH Worm Standard 22.1 22.1 26.5 20.9 22.0 22.4 22.4 17.4 13.3 12.4
Optional No. 1 13.3 9.1 16.6 12.1 12.8 11.8 11.8 9.7 7.9 7.7
Optional No. 2 17.7 18.1 — — — — — — — —
Numeric Ratio 13.3 9.1 8.6 7.5 6.9 5.3 5.3 4.6 3.9 —
 
Efficiency Rating (%) - 316SS Worm Standard 20.3 21.1 25.1 20.3 18.8 17.9 17.9 17.0 12.9 12.1
Optional No. 1 10.9 12.0 15.0 11.5 10.7 9.3 9.3 9.3 7.5 7.4
Optional No. 2 15.5 16.8 — — — — — — — —
Numeric Ratio 10.9 8.0 7.5 5.8 5.4 4.5 5.0 4.5 3.6 —
 
Key Torque (in-lb) - 17-4PH Worm Std. & Opt. 460 1750 4700 7580 10625 14000 16800 26500 47110 118200
Numeric Ratio 460 1599 4077 6645 9369 11474 13770 18561 30970 —
 
Key Torque (in-lb) - 316SS Worm Std. & Opt. 153 581 1565 2527 3538 4665 5600 8828 15697 39396
Numeric Ratio 211 460 551 959 1199 2328 2800 2358 4087 —
 
Weight with 6 inch Stroke (Raise) (lb) 17 35 52 66 93 160 160 240 410 1200
 
Weight per additional 1 inch Stroke (Raise) (lb) 0.3 0.9 1.4 1.5 2.6 2.5 2.5 3.7 5.5 9.0
Note: For loads from 25% to 100% of actuator capacity, torque requirements are approximately proportional to the load. Contact Duff-Norton Customer Service for motorized performance.