Three things you should consider, when choosing the right gearbox

Are you in doubt about what type of gearbox you need? In this article we will go through three of the most important things you need to consider before you decide. 

Stainless motor and gear installed

It is important to install the right gearbox in your production environment, as it can have great costs if you choose the wrong gearbox. Therefore, it can be an advantage to think about your needs before you make the decision.

1. The material has an impact on the lifetime of the gearbox

Cast iron gearboxes are made of a stable and sturdy material that decreases noise and reduces vibration. But the gearbox will corrode in time if you expose it to water or saltwater. The gearbox is painted to protect the steel for a longer period of time, however, they are best suited for use in environments, where they are not exposed to high pressure cleaning or cleaning detergent, as the paint will peel off over time.

Gearboxes made of AISI 304/EN 4301 stainless steel or AISI 316L/EN 4404 acid-proof stainless steel have a high resistance to corrosion and can withstand saltwater as well as the use of chemicals or cleaning detergents. The gearbox is not painted, and as a result you can safely use it in the food industry, without concerns about contamination of the end product.

2. The surface of the gearbox: High demands for hygiene?

Cast iron gearboxes are cast to reduce the weight and use of material. The material also has the advantage that it easily releases heat to the surroundings, and therefore you do not risk overheating of the gearbox. However, the casting process gives the material a rough surface with many cavities and recesses. This makes the gearbox unsuitable for industries where it comes into contact with food.

Stainless steel gearboxes are ideal for industries with high demands for hygiene, and where you use aggressive cleaning methods. The gearbox has a cleaning-friendly design with a smooth surface and rounded edges. In addition, the gearbox has no flanges or recesses, and you avoid bacterial growth and accumulation of impurities.

3. IP-classification: A transmission solution that withstands high pressure cleaning

Cast iron gearboxes have a protection degree of IP65 and can withstand cleaning with spraying of water from 2,5-3 meters with a pressure of 12,5 litres of water per minute from all directions. The surface of the gearbox and the painting cannot withstand high pressure cleaning or cleaning products. If you use these remedies, you will find that the painting peels off, and the gearbox will rust and corrode.

Stainless steel gearboxes have a protection degree of IP65 as a minimum. In addition, a stainless steel gearbox mounted with a motor has a protection degree of IP66 at the joint, if you use a nitrile gasket. This means that the joint can withstand cleaning with powerful water jets with a pressure of 100 litres of water per minute.

If you need to clean your gearbox with high pressure cleaning or at high temperatures, you can use a POM (polyoxymethylene) cover to reach a protection degree of IP69K. The closed POM cover is mounted on the gearbox opposite the output shaft to protect the nitrile gasket of the gearbox. In the same way, you can have a torque arm mounted at the output shaft to protect the gasket against high pressure cleaning aimed directly at the sealing.

Why you should choose a stainless steel solution for food production


Cast iron gearboxes and motors

Stainless steel gearboxes and motors

An old aluminium gearbox with motor

Stainless steel gearbox and motor

An old aluminium motor exposed to water or saltwater

Stainless steel motor - corrosion resistant


  • Rusts when exposed to water or saltwater.
  • Is painted for longer protection.
  • The paint peels off if exposed to chemicals or high pressure cleaning.
  • Has a high corrosion resistance.
  • Does not have paint that can peel off.
  • Can resist chemicals and saltwater.


  • Has a rough surface with recesses and cavities.
  • Has a smooth surface without flanges or recesses.


  • Has a protection degree of IP65.
  • Can withstand cleaning with water jets (12.5 litres per minute).
  • Has a protection degree of up to IP69K.
  • Can resist high pressure cleaning.


Yellow chromate cast iron gearbox with hollow shaft is installed in a wet environment

This yellow chromate cast iron gearbox with hollow shaft is installed in a wet environment, where it has been exposed to salt spray (salt fog) and frequent use of cleaning detergents. The two materials have very different resistances to corrosion. While the gear housing is rusty, the stainless steel hollow shaft has not corroded.

 Aluminum gearbox corrosion

Just like the cast iron gearboxes aluminium gearboxes will corrode if they are not painted, aluminium cannot withstand exposure to acidic or alkaline environments. If you use cleaning agents, you will, as a result, experience a strong corrosion of the metal.