How to Know When You Should Use a Bearing Heater

How do you mount your bearings? Oil bath? Open flame? Mounting kit? Bearing heater? Brute force? Well, what if we told you that one in six premature bearing failures occur as a result of poor fitting practices. The force required for mounting rises as the bearing size increases, this makes it essential to ensure you're getting it right.

Heat is one of the most effective methods used to mount bearings. This is because when the inner ring is heated, it expands to allow the bearing to slide onto the shaft without the need for excessive force. Although there are many ways to heat a bearing, the best method is using an induction bearing heater, particularly when mounting larger bearings.

But, how do you know when to use an induction heater and what temperature you should heat your bearings to?

When should you use a bearing heater?

Induction heaters provide a controlled heating method that enables users to set the correct temperature required to mount the bearing—preventing users from heating bearings unevenly, causing irrevocable damage. User safety is also improved by removing the need for alternative heating methods such as oil baths and open flames.

Although induction bearing heaters are often ideal for mounting many types of bearing, it is not always the best option for some bearings. For example, if your bearing has an outer diameter of 100mm or less, it is classed as a small bearing; therefore, it can be cold mounted. There can also be other limitations depending on the materials used in the bearing, such as non-metallic compounds.

What temperature should you heat your bearing to?

Generally, a bearing should be heated to 80-90°c above the temperature of the shaft it is being mounted on. This will allow the bearing to slide onto the shaft easily, and as the temperature cools, a strong shrink connection will be made between the shaft and bearing. However, you should never heat a bearing above 125°c as this can cause the bearing harm.

Additionally, if your bearing contains any non-metallic components such as polyamide cages or rubber seals, it is not advisable to heat above 120°c. Solid oil bearings should not be heated above 80°c. It is always advisable to check manufacturer guidelines before heating your bearings.

Where can you get an induction bearing heater?

ACORN® can offer a large selection of stocked induction bearing heaters from leading suppliers, including SKF and NSK. Alternatively, SKF Induction Heaters are available for hire, ranging from the portable TWIM15 heater to the TIH220m heater for large size bearings. Contact our knowledgeable team today.