The M3PHF70 industrial gear unit is the size 70 member of the hollow-shaft, foot-mounted industrial range. Three all-helical stages on parallel axes carry the torque, and the low-speed shaft is bored to accept the driven machine shaft directly, so no output coupling and no separate pedestal bearing are needed. The unit sits on industry-standard foot pads while the machine shaft passes straight through the output bore.
A Hollow-Shaft Build in the Size 70 Industrial Frame
Every frame of this industrial gear unit family shares one design language: a horizontally split cast-iron housing that opens for tooth inspection without being lifted off its base, case-hardened and ground helical gearing in all stages, and bearing spans sized for the overhung pull that pulleys and sprockets impose on the output shaft. At size 70 the housing sits mid-band in the horizontal ladder, the frame class heavy plants specify for continuous drives on conveyors, feeders, mills and thickener mechanisms that run loaded every shift.
Decoding the M3PHF70 Type Code
| M3 | Industrial gear unit family, three helical gear stages |
| P | Parallel-shaft helical layout (the R code marks the bevel-helical right-angle build) |
| H | Hollow low-speed shaft - keyed fit or shrink-disc clamping (S marks a solid shaft) |
| F | Foot mounting on industry-standard bases (T marks torque-arm mounting) |
| 70 | Frame size 70, mid-range of the horizontal band 50 to 90 |
The letters describe function and the number describes size, so the same size 70 housing also ships as a solid-shaft foot build, a hollow-shaft torque-arm unit or a right-angle bevel-helical drive. A plant that has standardised on this range keeps one oil specification, one set of inspection intervals and one spare-parts logic across every drive point - the practical reason industrial buyers work frame by frame instead of machine by machine.
Continuous drives that spec this construction:
- Long overland conveyor head drives where the motor must sit beside the belt
- Kiln and cooler shell drives on existing trunnion supports
- Apron and plate feeders under primary crushing stations
- Rotary drum scrubbers and trommel screens in aggregate plants
- Slurry and tailings pump sets in mineral processing circuits
- Coke oven and sinter plant conveyor transfer points
Heavy-Duty Duties across Process Industry
The hollow-shaft foot build earns its place where the machine shaft is already carried by its own bearings and the drive has to be dropped in beside it: conveyor head pulleys, feeder shafts, mill trunnion drives, thickener rake arms. Omitting the coupling removes the flexible element that ages and the alignment that drifts after foundation settlement. The condition to check is the machine shaft itself - it must be stiff enough to take the gear unit and its reaction without adding a support. WGT reviews the shaft geometry and the bore detail against the outline drawing on every enquiry.
Drawings, Selection and Supply
WGT issues the M-series catalogue and the size 70 outline drawing as PDF downloads, so the bore diameter, keyway or shrink-disc seat, foot pattern and motor interface can be verified against the installation before any commitment. Send the driven machine, the motor power and speed, the required output speed, the machine shaft diameter and the running hours per day; the rated torque is checked against those inputs and a written quotation follows. Each unit leaves the factory tested, packed in an export wooden crate and covered by a one-year warranty.
Selection Example: Typical duty point
A typical enquiry for this frame reads like this: 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. That is the whole calculation. If your duty involves heavy starting, frequent reversing or many stops per hour, tell us and we raise the service factor.
Which Frame Size Do You Need?
| Model | Centre distance | Output | Typical duty |
|---|
| M3PSF50 | size 50 | solid shaft, foot | conveyors, feeders |
| M3PSF60 | size 60 | solid shaft, foot | crushers, mixers |
| M3PSF70 | size 70 | solid shaft, foot | ball mills, shredders |
| 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 |
Foot-mounted frames are listed below; torque-arm (T), hollow-shaft (H) and vertical (V) variants are available across the size range. Ask for the outline drawing to check the interface before ordering.
Answers to Common Questions
What is the service factor and how is it applied?
The service factor is a multiplier applied to your required torque to cover shocks and duty class - typically 1.0 for uniform duty, 1.25 for moderate shocks, 1.5 or more for heavy shock loads. Send us the driven machine and duty and we will apply the correct factor.
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.
![gearbox sizing steps for engineers]()
Four steps from your application data to a firm model number.
Case Notes from the Field
Lime kiln auxiliary drive
A lime producer fits a smaller industrial gear unit as the auxiliary drive of its rotary kiln. Turning the kiln slowly during shutdowns and start-ups is exactly the low-speed, high-torque duty the frame was chosen for.
Tunnel boring backup drive
A tunnelling contractor uses industrial gear units on the backup gantry conveyors of its TBM. The units arrived dimensionally matched to the gantry interfaces, so installation took hours rather than days.
![industrial gear unit application overview]()
A cross-section of the installations we supply every month.
Drive Down? Ask About Priority Builds
A drive is down right now? Try the WGT Motor & Gearbox Online Selection System, then send the result sheet - we return a complete datasheet, drawing and price the same day.
Priority builds slot into the next production run, and urgent units can be air-freighted within days of payment. Describe the failure and the machine - we tell you honestly what is possible. Looking for a gearbox for wastewater treatment? Tell us the duty point and we will confirm the model in writing.
