Metric Screw Jacks

Joyce metric screw jacks, series MWJ, are specifically designed for applications that must be fully metric. Both upright and inverted configurations operate at full capacity whether the load is in tension or compression. These jacks are commonly used in OEM machinery manufactured in the U.S. and shipped to other countries. They are fully interchangeable with several European products.

  • Self-locking metric (trapezoidal) lifting screws
  • Fully metric mounting hole locations, diameters, and fasteners
  • Alloy steel input shafts
  • Aluminum bronze wormgears and Traveling nuts
  • Tapered roller or ball thrust bearings provide rugged reliability
  • Protective boots available
  • Anti-backlash devices available
  • Joyce/Dayton can customize to your specifications
  • Custom finishes available

Wormgear cutaway illustration - Small

Parts list and exploded views are included in the O&M Manual. Serial numbers are attached to the product housing.

Joyce/Dayton provides motor controls ranging from simple Motor Starters to complex positioning systems and Custom controls. Every system that is powered by an electric motor requires a control system. At Joyce, we know that choosing the best option can sometimes be a challenge. That’s why our Engineers are available to help you through the process.

Anti-backlash Devices

  • Available for machine screw jacks
  • Available for metric (trapezoidal) jacks
  • Limits lifting screw endplay
  • Anti-backlash Devices


  • Standard 200 or 1024 PPR
  • Quadrature wave form
  • Stainless steel encoder
  • Absolute encoder
  • Encoders


  • Enamel finish (standard)
  • Epoxy finish
  • STEEL IT® epoxy
  • Outdoor paint process
  • Custom finishes available
  • Anodized (250-lb to 1-ton)
  • Nickel, Xylan®, Armoloy®
  •  Finishes



Follower Nuts

  • For KFTN jack
  • For translating jack

Hand Wheels

  • 4" – 12" dia. (standard)
  • Aluminum (standard)
  • Stainless steel available
  •  Hand Wheels


Input Shaft (worm)

  • Square or hex to fit tool
  • Special lengths
  • 17-4 stainless steel available
  • Metric diameters available
  • One side can be cut off
  • Other modifications available
  • Input shaft cover available

Limit Switches

  • Rotary cam (2-4 switches)
  • SPDT standard
  • DPDT available
  • Explosion proof available
  • Limit Switches


  • Standard grease temperature range (40°F to 220°F)
  • Low temperature option
  • High temperature option
  • Food grade option

Machine Screws

  • Right hand thread standard
  • Left hand thread available on many models
  • Special material available
  • Special pitch/lead available
  • Special finishes available
  • Special machining options
  • Special end conditions available

Mechanical Counters


Motor Mounts

  • NEMA mounts available on 2-ton to 20-ton wormgear jacks and electric cylinders
  • NEMA mounts included on integrated actuators
  • Servo motor mounts available on 2-ton to 10-ton jacks and electric cylinders, special mounts available
  • Custom mounts available
  • Motor Mounts and Stock Motors


  • 0-10V (POTA)
  • 4-20mA (POTB)
  • 0-10V with limit switches (POTC)
  • 4-20mA with limit switches(POTD)
  • IP65
  • Potentiometers

Protective Boots

  • Protection from dirt and dust
  • Guard against moisture
  • Guard against corrosive contaminants
  • Neoprene coated nylon (std)
  • Special materials available
  • Boot Material Chart
  • Protective Boots

Screw Stops

  • Standard on ComDRIVEs
  • Adjustable
  • Bolt- on

Thrust Rings

  • Used in applications where static loads exceed jack capacity

Sample Part Number:

Click on the part number to reveal additional informaton about jack designs and shaft codes.

Model Number

10 kN 25 kN 50 kN 100 kN

Jack Configuration



End Conditions

(plain end)

(load pad)

(threaded end)

(male clevis)

Jack Designs


K=Keyed for Non Rotation

N=Traveling Nut

D=Double Clevis

R=KFTN Trunnion*

* Standard trunnion mounts available on 2-ton through 20-ton jacks.

Metric Screw Jack Rise

Rise is travel expressed in millimeters and not the actual screw length.

Left Side Shaft Code

Right Side Shaft Code




Optional Shaft Codes

Screw Stops and Boots

Screw stops are optional on metric screw jacks. When specified, the closed height of the jack and/or the protection tube length may be increased. When boots are added to metric screw jacks, the closed height of the jack may be increased.

Mechanical Counters

CNT0=0.001" Increments
Note: Contact Joyce/Dayton for availability and options.

Hand Wheels

HW04=4" dia
HW06=6" dia
HW08=8" dia
HW10=10" dia
HW12=12" dia

Geared Potentiometers

POTA=0-10V (IP65)
POTB=4-20MA (IP65)
POTC=0-10V w/2 switches*
POTD=4-20MA w/2 switches*
*Optional IP65 rating available

Encoders and Electronic Limit Switches

ELS2=2 Position Electronic Switch
ELS4=4 Position Electronic Switch
ELS6=6 Position Electronic Switch

Motor for Systems and Direct Drive

  • All standard motors are 3-phase, 208-230/460 VAC or 230/460 VAC. Other motor options are available. Specify the appropriate motor size from the chart on the right.
  • Refer to the "Additional Options" chart on the preceding page as needed.
  • Brake motors (M2) are recommended for jacks that are not self-locking, and jacks with double lead screws.
  • If the motor frequency will be varied to provide a "soft" start an inverter duty motor may be required.


Size Code
1/4 HP K
1/3 HP A
1/2 HP B
3/4 HP C
1 HP D
1-1/2 HP E
2 HP F
3 HP L
5 HP G
7-1/2 HP H
10 HP I
15 HP J

Motor Mounts

Ordering Example:
MMA A (Motor code from chart above)


Standard motor adapters are aluminum

Mechanical Limit Switches

Ordering Example:
LA (Models) 1(Number of DPDT Switches) 3(Available Positions)

Model Code   Available Positions
LS7-402 LI

Number of DPDT Switches

NOTE: Will always be 0 for LS7 models

  1 2 3 4 5 6 7 8
LS8-402 LA Left Side Shaft Options
LS8-504 LB
LS9-502 LC
LS9-503 LD Right Side Shaft Options
LS9-504 LE
LS9-505 LF
LS9-506 LG
  • 2, 3, 5, 10, 15, and 20 ton jacks are available with positions #1, #3, and #5
  • 25, 30, 35, 50, 75, 100, and 150 ton jacks are available with positions #1, #4, #7, and #8

These positions are not standard. Contact Joyce/Dayton with your requirements.

LS9-507 LH

Additional Options

  • X=Standard Jack, no additional options
  • S=Additional Specification Required (comment as necessary)


  • A=Split Nut
  • A90=A90 Design
  • A95=A95 Design

Protective Boots

  • B=Protective Boot
  • D=Dual Protective Boot


  • F1=Do Not Paint
  • F2=Epoxy Paint
  • F3=Outdoor Paint Process

Motor Options

  • M1=Less Motor
  • M2=Brake Motor
  • M3=Single Phase Motor (120VAC)
  • M4=50Hz Motor


  • H1=High Temperature Operation
  • H2=Food Grade

Screw Stops

  • ST0=Extending
  • ST1=Retracting
  • ST2=Both
  • Specify as many options as needed
ModelCapacityScrew Diameter (mm)Thread Pitch/LeadWorm Gear RatioWorm Shaft Turns for 1mm TravelTare Torque (Nm)Starting Torque (Nm)Operating Torque (Nm)Efficiency Rating % ApproxScrew Torque (Nm)Basic Jack Weight (Kg)Jack Weight 
(Kg) per 25mm Travel
MWJ51 10 kN 20 5mm 5:1 1 0.33 .95W* .70W* @ 
500 RPM
22.7 2W* 2.7 0.14
MWJ201 10 kN 20 5mm 20:1 4 0.33 .41W* .23W* @ 
500 RPM
17.0 2W* 2.7 0.14
MWJ62.5 25 kN 30 6mm 6:1 1 0.67 1.01W* .81W* @ 
500 RPM
19.6 3W* 6.8 0.18
MWJ122.5 25 kN 30 6mm 12:1 2 0.67 .62W* .45W* @ 
500 RPM
17.8 3W* 6.8 0.18
MWJ242.5 25 kN 30 6mm 24:1 4 0.67 .44W* .27W* @ 
500 RPM
14.7 3W* 6.8 0.18
MWJ65 50 kN 40 9mm 6:1 0.67 1.13 1.64W* 1.14W* @ 
300 RPM
20.9 4W* 14.5 0.32
MWJ125 50 kN 40 9mm 12:1 1.33 1.13 1.03W* .64W* @ 
300 RPM
18.7 4W* 14.5 0.32
MWJ245 50 kN 40 9mm 24:1 2.67 1.13 .74W* .39W* @ 
300 RPM
15.2 4W* 14.5 0.32
MWJ810 100 kN 55 12mm 8:1 0.67 2.26 1.53W* 1.18W* @ 
200 RPM
20.2 5W* 19.5 0.59
MWJ2410 100 kN 55 12mm 24:1 2 2.26 .76W* .49W* @ 
200 RPM
16.1 5W* 19.5 0.59


*W: Load in kN.
Tare Torque: Initial torque to overcome seal and normal assembly drag. This value must be added to starting torque or operating torque values.
Starting Torque: Torque value required to start moving a given load (dissipates to operating torque values once the load begins moving).
Operating Torque: Torque required to continuously raise a given load at the input RPM listed. Note: If your actual input RPM is 20% higher or lower than the listed RPM, please refer to our JAX program to determine actual torque values at your RPM.
Screw Torque: Torque required to resist screw rotation (Translating Design Jacks) and traveling nut rotation (Keyed for Traveling Nut Design Jack).
Lead: The distance traveled axially in one rotation of the lifting screw.
Pitch: The distance from a point on a screw thread to a corresponding point on the next thread measured axially.