The M3RHF70 right angle gear unit combines two installation solutions in one size 70 industrial housing: a spiral-bevel input stage that turns the motor 90 degrees, and a hollow low-speed shaft that takes the driven machine shaft straight into the output bore. Between them they shorten the drive train to the minimum - no motor projecting along the machine axis, no output coupling, no intermediate bearing pedestal.
Right-Angle Input, Hollow Output, Mid-Range Frame
Size 70 sits in the middle of the horizontal industrial band, where drives run loaded every hour of every shift but the plant still wants a compact footprint at the drive point. The bevel stage solves the layout problem - keeping the motor beside the machine rather than in line with it - while the hollow output solves the mechanical one, removing the coupling that would otherwise need re-centring after foundation settlement. Gearing is case-hardened and ground in every stage, bevel and helical alike, running in one oil sump inside a horizontally split cast-iron housing.
Reading the M3RHF70 Designation
| M3 | Industrial gear unit family, three gear stages |
| R | Bevel input stage giving a right-angle drive (P keeps all stages parallel) |
| H | Hollow low-speed shaft, keyed fit or shrink-disc connection (S marks solid shaft) |
| F | Foot mounting on industry-standard bases (T marks torque-arm mounting) |
| 70 | Frame size 70, mid-range of the horizontal build 50 to 90 |
Because the letters describe function and the number describes size, the same size 70 housing is also supplied as a right-angle unit with a solid output or as an all-helical parallel build with either shaft type. One dimension ladder, four installation styles, one maintenance doctrine - the reason heavy plants standardise on the industrial range rather than buying drive by drive.
Process lines where this build is the standard choice:
- Inclined and swan-neck conveyors where the motor has to sit off the belt line
- Bucket elevator head shafts driven straight through the hollow output bore
- Rotary valves, airlocks and discharge gates below silos and bunkers
- Paddle, ribbon and plough mixers in heavy chemical and fertiliser service
- Drum drives on rotary screens, trommels and sizing scrubbers
- Travel and slewing drives on gantry cranes and portal structures
When the R-H Combination Pays Off
The combination earns its place where the layout is tight and the machine shaft is already in position: inclined conveyors running alongside a wall, elevator head sections inside a tower, rotary valves and mixers fed from a compact skid. Removing the coupling also removes the flexible element that ages and the pedestal bearing that needs greasing, which matters on drives that run unattended for long stretches. Where the machine shaft is long or lightly supported, WGT will advise whether the hollow-shaft foot build, the torque-arm variant or a solid-shaft drive suits the duty better before the drawing is issued.
Enquiry, Drawing 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 checked before ordering. Send the driven machine, the motor power and speed, the required output speed, the machine shaft diameter and the daily running hours; the selection is verified against those figures, quoted in writing, factory-tested and packed in an export wooden crate under a one-year warranty.
How Customers Use This Unit
Sugar mill bagasse conveyor
A sugar mill moves wet bagasse on conveyors driven by industrial gear units. High moisture, fibrous material and sticky residue are the daily conditions, and the sealed housings have kept lubricant clean between oil changes.
Slag handling crane
A steelworks drives the long-travel motion of a slag-handling crane with industrial gear units on torque arms. Heat radiation from the slag pot is handled by the increased clearance and standard high-temperature paint.
What Engineers Ask Us
What warranty and documentation come with the gearbox?
A one-year warranty covers material and workmanship. Each unit ships with a test record (noise, temperature rise, backlash), a dimension drawing and an installation manual.
How do I calculate the ratio I need?
Divide motor speed by the target output speed (i = n1/n2), then check the required torque against the rating table with your service factor. The online selector below does this automatically.
Model Table: Frames, Shafts and Duty
| Model | Centre distance | Output | Typical duty |
|---|
| M3RHF70 | size 70 | hollow shaft, foot, right-angle | agitators, drum drives |
| 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 |
| M3PHT80 | size 80 | hollow shaft, torque arm, parallel | shaft-mounted conveyors |
| M3RHT90 | size 90 | hollow shaft, torque arm, right-angle | heavy shaft-mounted drives |
Larger size numbers mean higher torque capacity and larger shafts. Because interfaces follow the common industrial dimensions, a size-for-size change is the normal upgrade route for these industrial units.
Selection Example: Elevator head shaft drive
Take a 75 kW motor at 1480 rpm turning a bucket elevator head shaft at 17 rpm. The ratio follows directly: 1480 / 17 = 87, so a ratio near i=87 is selected. In this case the hollow bore takes the head shaft directly while the bevel input keeps the motor inside the tower footprint. Note that the ratio comes from speeds alone, while the frame size depends on torque and service factor - never size a unit on ratio only.
![industrial helical gearbox selection chart]()
A quick visual of the selection sequence for a industrial helical unit.
![M3 series gear reducer installation examples]()
Application coverage of the the M3 series.
Custom Shafts and Ratios for OEM Builds
Non-standard interface? Prefer to check the figures yourself? The WGT Motor & Gearbox Online Selection System gives you the model, torque margin and ratio before you ask us.
Splined, extended or flanged output shafts and special ratios are quotable for OEM volumes. Tooling cost is amortised across the order, and the drawing approval cycle starts the day you ask. Looking for a speed reducer for bucket elevator? Tell us the duty point and we will confirm the model in writing.
