The M3PSF70 parallel shaft industrial gearbox occupies the middle of the M-series size ladder, where the step from size 60 finally covers drives that run loaded every hour of every shift. Three helical stages on parallel axes, a horizontally split cast-iron housing, and a foot-mounted solid output shaft: the same architecture as the smaller frames, scaled so the bearings and shaft diameters can take sustained overhung load from a driven pulley or sprocket.
Sized for Continuous Torque, Not Peak Torque
What separates the size 70 frame from the frames below it is thermal and bearing capacity rather than headline gear rating. A drive that runs three shifts at full load lives or dies on oil sump behaviour, bearing life and shaft deflection, and all three scale with the frame. This is why the size 70 unit appears again and again in mill circuits and bulk handling lines, where the machine is never stopped long enough for peak-load thinking to matter. Because every stage is helical, efficiency stays high across the full ratio band, which keeps motor current and heat generation predictable at low output speeds.
Reading the M3PSF70 Type Code
| M3 | M-series industrial gear unit with three gear stages |
| P | Parallel-shaft helical layout (the R code marks the bevel-helical right-angle build) |
| S | Solid low-speed shaft, keyed for a standard coupling |
| F | Foot mounting (the T suffix would indicate torque-arm mounting) |
| 70 | Frame size 70 within the horizontal industrial range |
The code is read left to right, so a buyer can confirm shaft type and mounting from the designation alone before opening a drawing. Vertical builds of the same frame use a letter V in the code and the same gear geometry, which lets a plant run one spare-parts policy across horizontal and vertical installations.
Proven duty points across heavy industry:
- Mine hoists, winches and heavy rope-driven haulage
- Cement raw mills, coal mills and vertical roller mill drives
- Bulk terminal stackers, reclaimers and travelling shiploaders
- Steel plant cranes and ladle transfer bogies
- Chemical and fertiliser granulation drums
- Pulp and paper press sections and rewinders
Frame Sizes and Their Build Variants
| M3PSF50 / 60 | Smaller three-stage foot-mounted frames with solid shafts |
| M3PSF70 | This frame size 70, three stages, foot mounted, solid shaft |
| M3PSF90 | Size 90 top of the horizontal three-stage foot-mounted band |
| M3PHF70 | Same frame with a hollow low-speed shaft, key or shrink-disc connection |
| M3PHT70 | Hollow shaft with torque-arm mounting for shaft-mounted conveyor drives |
| M4PSF / M5PSF | Four and five-stage builds when the required ratio exceeds the three-stage band |
Because the letters are independent of the size number, the same size 70 housing accepts a solid or hollow output and a foot or torque-arm mounting. That flexibility is the practical reason the M-series is specified as a plant standard rather than a one-off purchase.
Ordering, Drawings and Delivery
WGT ships the M-series catalogue together with the size 70 outline drawing as PDF downloads, so shaft height and bolt pattern can be checked against an existing foundation before the order is placed. To confirm a selection, send the driven machine, motor power and speed, required output speed and the daily running hours; the rated torque is verified against those inputs and a written quotation follows. Units are factory-tested, packed in an export wooden crate and covered by a one-year warranty.
Field Applications
Grain terminal elevators
A grain terminal powers its bucket elevators with gear reducers. The anti-run-back option holds the loaded buckets during power cuts, and standard interface dimensions meant the old foundations were reused as they were.
Pallet lift in a warehouse
A logistics integrator selected units for pallet lifts. The hollow output bore carries the lift screw directly, and one year of three-shift operation has passed without a single seal replacement.
![where gear reducers are used in industry]()
Where these units are installed across industry.
Selection Example: Typical duty point
Worked example for this frame - the motor runs at four-pole speed and the machine needs a slow output. Motor speed divided by the target output speed gives the ratio, rounded to the nearest available step, and the required torque with the service factor then fixes the frame size. Once the ratio is fixed, check the required output torque against the rating table with the service factor applied - that is what decides the frame, not the ratio alone.
![gearbox selection guide: speed, torque, service factor]()
How a ratio and a frame size are determined, step by step.
Frame Sizes and Typical Duties
| Model | Centre distance | Output | Typical duty |
|---|
| M3PSF70 | size 70 | solid shaft, foot | ball mills, shredders |
| M3PSF50 | size 50 | solid shaft, foot | conveyors, feeders |
| M3PSF60 | size 60 | solid shaft, foot | crushers, mixers |
| M3PSF80 | size 80 | solid shaft, foot | kilns, heavy conveyors |
| M3PSF90 | size 90 | solid shaft, foot | mill and kiln drives |
| M3RSF50 | size 50 | solid shaft, foot, right-angle | inclined conveyors, elevators |
| M3RSF60 | size 60 | solid shaft, foot, right-angle | screw classifiers, feeders |
| M3RHF70 | size 70 | hollow shaft, foot, right-angle | agitators, drum drives |
| M3PHT80 | size 80 | hollow shaft, torque arm, parallel | shaft-mounted conveyors |
| M3RHT90 | size 90 | hollow shaft, torque arm, right-angle | heavy shaft-mounted drives |
The size number is the key dimension that steps up torque capacity through the range: 50 to 90 in horizontal builds, 10 to 90 in vertical builds. Gearing philosophy is shared across the family.
From Duty Point to Delivery in One Working Day
Stop guessing the ratio. Engineers can size the unit themselves in the WGT Motor & Gearbox Online Selection System - input speed, torque and duty, get the model instantly.
Tell us what the machine does and how hard it works; we calculate the ratio, apply the service factor and send back the drawing and quotation within one working day, including sea-freight and air-freight options. Looking for a gearbox for mixer and agitator? Tell us the duty point and we will confirm the model in writing.
Common Questions from Buyers
What ambient temperature range can the unit work in?
Standard units suit -10 to +40 deg C ambient with the supplied mineral oil. For lower temperatures we fill with synthetic oil; for higher ambient or frequent starting we advise the next larger frame or an oil cooler.
What are the delivery lead times and shipping terms?
Standard lead time is 5-10 weeks ex-works, with popular ratios often available sooner. We quote EXW, FOB NINGBO / SHANGHAI or CIF, and urgent units can be air-freighted within 72 hours of payment.
What materials are used for the gears and shafts?
Gears are 20CrMnTi alloy steel, case-carburised to HRC58-62 over a tough HRC33-40 core. Input and output shafts are 42CrMo, quenched and tempered to HRC25-30. The housing is cast iron at HBS190-240.
