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SCREW JACK Duff-Norton line of screw jacks (mechanical actuators) includes mechanical actuators (machine screw and ball screw) ranging in size from 1/4 ton to 350 tons, stainless steel machine screw actuators, micro-miniature actuators, high duty cycle actuators, motorized machine screw and ball screw actuators, electric cylinders and motor control systems. Accessories include miter gear boxes, c-face motor adapters, limit switches, transducers, visual and digital position indicators, couplings, ball screws and ball screw systems, and locking rings. Screw Jacks are also used for raising and lowering maintenance platforms, opening and closing air dampers, oven doors and sluice gates, and adjusting tooling machine beds, cable tension and workplace tables. In addition to the broad range of applications and industries for mechanical actuators, they are also used as alternatives to hydraulic and pneumatic systems.
Application Analysis Form

Duff-Norton Engineers will be pleased to make recommendations for your specific requirements. There is no obligation for this service - simply complete the form below.

If you would like to discuss your application with a Duff-Norton engineer, call 1-800-477-5002.

If you prefer,  Click Here to print a blank Application Analysis Form, complete the form, and send to Duff-Norton at the fax number or address shown below.

If you would like to send a sketch of your application or design drawings in complete confidence, mail or fax to:

Duff Norton Company
PO Box 7010
Charlotte, NC 28241
800-477-5002 TOLL FREE
704-588-1994 FAX

*Required Fields
Name *  
Company *  
Address *  
City *  
State *  
Zipcode *  
Phone *  
Email *  

Type of application

How many actuator units needed

Stroke (Raise)/Unit  in.

How many mitre gear boxes are needed?

Total working load  tons

Working Load per unit

Total static load

Static load per unit

Side thrust on lifting screw  lbs.

Off-center load on lifting screw  in. / lbs.

Operating cycles  days per week

 per hour

hours per day

Life expectancy (inches per cycle x cycles per hour x hours per day x days per year x years of service required)  in.

Lifting Speed  in/min.

Are controls required for your system


Mounting Position  Limit Switch (pg.121)
Reducer* (pg. 112)

Load type



Temp. range

Standard actuator model best suited to application

Ultimate use of actuator units

Quotation desired on the following quantities