STM RMI 70 7.5:1 Worm Gearbox – 28mm Hollow Bore

This STM RMI 70 7.5:1 worm gearbox is a compact right-angle reducer with a 28mm hollow bore output, built for faster conveyors, transfer systems, packaging equipment, and machinery where output speed needs to stay relatively high. The RMI 70 frame uses a die-cast aluminium housing, modular IEC motor input options, and the proven STM wormgear design for quiet running and dependable industrial service.

---

Gearbox Overview

The RMI 70 size is suited to applications needing a worm gearbox that is a larger aluminium worm gearbox for heavier-duty industrial duties. With a 7.5:1 reduction ratio, this version is typically chosen where higher output speed and lighter reduction are required, while keeping the simplicity and compactness of a single-stage STM worm gearbox.

---

Why Choose This Configuration?

This exact model is best suited to buyers who specifically need an STM RMI 70 gearbox with a 7.5:1 reduction ratio and 28mm hollow bore. Compared with lower ratios it provides more speed reduction and torque multiplication, while compared with higher ratios it retains a more practical output speed for many industrial drives.

---

Technical Details

Model: STM RMI 70
Gearbox type: Single-stage right-angle worm gearbox
Ratio: 7.5:1
Output bore: 28mm hollow bore
Housing material: Die-cast aluminium
Indicative gearbox weight: 7.5kg
Mounting positions: M1, M2, M3, M4, M5, M6
Ordering note: For sizes 28 to 70, no mounting-position specification is required in the order and units are supplied with plugs arranged for M1 as standard
Lubrication: Factory-filled lubricant; sizes 28 to 70 use the standard sealed arrangement without breather-plug requirement
Construction features: Die-cast aluminium housing with STM involute ZI wormgear profile for efficiency and quiet running

---

Internal Links & Compatible Options

Same gearbox size, different ratios: explore the closest STM RMI 70 ratio options.

Same ratio, different gearbox sizes: explore nearby sizes offering a 7.5:1 ratio.

More STM gearboxes: Browse all STM RMI 70 gearboxes Browse all STM worm gearboxes

Helpful calculators:
Gearbox Ratio & Speed Calculator |
Output Torque Calculator

---

Frequently Asked Questions

What does a 7.5:1 worm gearbox do?

A 7.5:1 worm gearbox reduces input speed by a factor of 7.5, increasing available output torque while lowering output speed for controlled mechanical drive.

What is the STM RMI 70 gearbox commonly used for?

The STM RMI 70 is commonly used on conveyors, packaging machinery, feeders, automation equipment, and general industrial systems that need compact right-angle power transmission.

Is this gearbox supplied with a 28mm hollow bore?

Yes, this version is configured with a 28mm hollow bore output to suit compatible driven shafts and coupling arrangements.

What mounting positions can this gearbox be used in?

STM RMI units support M1, M2, M3, M4, M5, and M6 mounting positions. On smaller sizes such as this range, the gearbox is supplied arranged for M1 unless a different arrangement is specified where relevant.

What housing material is used on this STM RMI gearbox?

For the RMI 70 size in this range, the housing is die-cast aluminium, giving a good balance of strength, weight, and corrosion resistance for industrial use.