Stainless Steel Screw Jack
Built for wet, corrosive & harsh environments. Customizable for medical, food & underwater use. 2.5–25 tons.
SSJW SERIES
Classic Stainless Steel Screw Jack
Our classic SSJW series stainless steel screw jack features a heavy-duty trapezoidal screw, precision worm gear drive, and rugged stainless steel housing — delivering dependable linear motion for corrosive and washdown environments at a competitive price.
Available in 5 standard sizes with load capacities from 2.5 to 20 tons, with custom configurations up to 30 or 50 tons. Choose translating-screw or rotating-screw designs in upright or inverted mounting. Ideal for low-speed, high-load positioning in food processing, marine, water treatment, and general industrial applications.
SSJC SERIES
Cubic Stainless Steel Screw Jack
Our premium SSJC series cubic stainless steel screw jack is engineered as a high-performance, high-precision alternative to leading European brands — with dimensionally interchangeable mounting for direct drop-in replacement.
The compact cubic housing enables flexible multi-face mounting and can be used individually or in synchronized multi-jack systems. Available in 5 sizes from 2.5 to 20 tons (custom up to 50 tons), with optional anti-backlash, protective bellows, and limit switches. Ideal for automated machinery, steel processing, and OEM applications requiring precision and reliability.
SIJIE
Frequently Asked Questions
Find answers to common questions about stainless steel screw jacks — including material grades (304/316), IP protection, self-locking, load capacities, washdown suitability, and more. Can’t find what you need? Our engineering team is here to help (Email: info@sjmotion.com).
Q1: What is a stainless steel screw jack used for?
A stainless steel screw jack converts rotary motion into precise linear motion, built entirely from corrosion-resistant stainless steel. It is used in food processing,pharmaceutical, marine, water treatment, pulp & paper, and other environments where moisture, chemicals, or regular washdown would damage ordinary cast-iron jacks.
Q2: Are ball screw jacks self-locking?
No. Due to their high efficiency (typically above 50%), ball screw jacks are not self-locking. When power is removed, the load can back-drive and drift. To hold position, you must use a brake motor, an external brake on the input shaft, or another mechanical locking device. This is a critical safety consideration during selection.
Q3: What is the difference between a ball screw jack and a trapezoidal screw jack ?
The key difference is the friction mechanism. A trapezoidal screw jack uses a sliding trapezoidal thread (metal-on-bronze), offering lower cost and inherent self-locking, but lower efficiency (20-35%) and limited duty cycle. A ball screw jack uses recirculating balls, delivering more than 50% efficiency, higher speeds, longer life, and suitability for high-cycle automation – but it is not self-locking and requires a brake or external locking device. Ball screw jacks also require up to two-thirds less input torque than equivalently rated trapezoidal screw jacks.
Q4: What load capacities are available for ball screw jacks?
Ball screw jacks are available in a wide range, from 5 kN (0.5 ton) for light-duty precision positioning up to 1000 kN (100 tons) for heavy industrial lifting. Common standard sizes include 10 kN, 25 kN, 50 kN, 100 kN, 200 kN, and 500 kN. Custom capacities and stroke lengths can be engineered for specific applications.
Q5: How efficient is a ball screw jack?
The ball screw and nut assembly itself typically achieves 80-95% efficiency. When combined with the worm gear reduction, overall jack efficiency ranges from approximately 45% to 60%, depending on gear ratio and load. This is significantly higher than trapezoidal screw jacks (20-35%), meaning less motor power is needed to move the same load.
Q6: How do I prevent the lifting screw from rotating?
Unlike tapezoidal screw jacks, ball screws cannot be keyed – a keyway would interrupt the ball track and cause ball loss. Instead, anti-rotation is achieved by fitting a square anti-rotation tube (square guide block) that slides inside a square stem tube, or by guiding the load externally. Note that adding an anti-rotation device increases required input torque by approximately 8%.
Q7: Will the load drift or fall when the motor is switched off?
Yes, a ball screw jack can drift after the motor is stopped because it is not self-locking. Drift is influenced by motor inertia, load weight, and gear ratio. To prevent drift and ensure safety, always install a brake of sufficient capacity on the input shaft or use a brake motor. For vertical loads, a holding brake is mandatory.
Q8: What industries and applications use ball screw jacks?
Ball screw jacks are widely used in: automotive assembly lines (chassis lifting, engine positioning), steel and metal processing (rolling mills, coil handling), packaging and printing machinery, food and beverage equipment, maritime and rail systems, aerospace test rigs, construction formwork, solar tracking systems, and general industrial automation requiring precise, repeatable linear motion.
Q9: What is the maximum duty cycle for a ball screw jack?
Thanks to low rolling friction and reduced heat generation, ball screw jacks can handle higher duty cycles than trapezoidal screw jacks – often up to 30-50% in well-lubricated, properly sized applications. Exact limits depend on load, speed, lubrication, and ambient temperature. Continuous operation at high loads may require oil lubrication and thermal monitoring.
Q10: How should I lubricate and maintain a ball screw jack?
– Grease lubrication is standard for most applications. Use a high-quality lithium-based or EP grease suitable for ball screws.
– Relubrication interval: approximately every 100-300 operating hours (reduce to 100 hours under heavy loads or dusty conditions).
– Grease quantity: roughly 1 ml per cm of screw diameter per lubrication point, or until grease slightly escapes from the nut ends.
– Inspection: check for contamination, abnormal noise, or increased backlash every 6 months; keep the screw protected with bellows boots in dirty environments.
Q11: Can multiple ball screw jacks be synchronized?
Yes. Multiple ball screw jacks can be connected in tandem or multi-jack systems using bevel gearboxes,couplings, and drive shafts to achieve synchronized lifting. With a servo motor and closed-loop control,synchronization accuracy can reach within 0.05 mm. This is commonly used for lifting platforms, stage equipment, and large industrial structures requiring even load distribution.
Q12: What operating temperature range can ball screw jacks handle?
Standard ball screw jacks operate within -15 to +80 C (5 F to 176 F). Larger or heavy-duty models may extend to +100 C (212 F). For extreme temperatures (cryogenic or high-heat environments), special lubricants, seals, and materials can be specified. High-speed continuous operation may generate additional heat requiring cooling or oil lubrication.
Q13: Can ball screw jacks be customized?
Yes. Common customizations include: special stroke lengths, stainless steel screws and housings for food/corrosive environments, protective bellows boots, custom end fittings (top plate, clevis, plain end, threaded end), integrated position encoders, manual handwheel operation, special gear ratios, and complete multi-jack lifting systems with motors, gearboxes, and controls. In addition, we can completely customize alternatives to any European and American brands according to customer drawings.
Q14: What is the expected lifespan of a ball screw jack?
Ball screw life is typically calculated based on travel distance (e.g., 50 million revolutions or 10,000-50,000 km of travel, depending on load and lead). Under proper lubrication and within rated load/speed, a ball screw jack can provide many years of reliable service. The worm gearbox, when properly maintained, is often considered lubricated-for-life under normal conditions.
Q15: What is the lead time and shipping for ball screw jacks?
Standard models are typically available with 20-25 days lead time.Custom configurations may require additional engineering and production time. We offer EXW, FOB, and CIF trade terms, and can ship viasea freight for large orders or air freight/DHL express for samples and urgent deliveries. Contact our engineering team with your application specifications for a quotation and lead time estimate.
