By Peter Church
In our experience, a brush on formula, with high adhesion and a capillary action, as well as water-repellent, extreme pressure and anti-wear additives will deliver the best results for leaf chain lubrication.
Effective leaf chain lubrication is essential for maximising the chain’s service life, as well as ensuring the safe operation and a low total operating cost of the entire piece of materials handling equipment.
At the final stage of manufacturing, we immerse our leaf chains in a good quality chain oil and articulate them to ensure it fully penetrates the pin and link plate joints where it is needed.
However, this oil will likely need to be topped up during the chain’s service life and so we are regularly asked by customers for recommendations as to which oil they should use.
One thing customers should look for in the formula of their leaf chain lubricant is a creeping or capillary action. This draws the oil into tiny internal gaps in the chains.
Removing any load from the leaf chain and leaving it slack for 15-20 minutes will open the clearances and help more of the oil reach the load bearing area inside the chain.
Brush on vs. spray lubricant
We would also advise that customers look for a brush on formula, as opposed to an aerosol spray. Brushing the oil directly onto the leaf chain pin and plate joint will give it the best possible chance of soaking deep down into the chain.
When you are indiscriminately spraying lubrication on and around a leaf chain, a good portion of what’s delivered will coat the non-moving components that don’t need lubrication. In addition, these spray cans of chain lube may contain more propellant than lubricant and are often formulated for roller chains, not leaf chain.
We have found the following lubricants particularly suitable for leaf chain, although other companies may produce similar products.
- Molykote MKL-N
- Kluber Structovis BHD 75 S
- FUCHS FLT LUBE
Their features are:
· high adhesion to chain, meaning the oil stays where it is needed
· water-repellent additives to reduce corrosion on equipment operating outside or in damp environments
· a viscosity to easily penetrate internal surface areas without dripping
· extreme pressure and anti-wear additives to improve durability under heavy loads
Seek expert advice
Although we are happy to make basic lubrication recommendations to customers, we are not experts in this complex area. The science of interacting surfaces in relative motion, including friction, wear and the impact of lubrication, is known as tribology.
For detailed recommendations or complex applications, customers should speak to a specialist at a good lubricant company.
Motorbike vs. leaf chain lubrication
A final point to bear in mind is that much of the research on chain lubrication has been carried out for chains used to transmit rotary power, such as motorbikes, bicycles and roller chain drives. These chains and their applications are very different to lead chain.
They are made of four parts – links, rollers, bushes and pins – and lubrication is required between the bush and inside of the roller, where the clearance is bigger than between leaf chain link plates and pins. These kinds of chains also operate a higher speeds and temperatures, and lubricant is applied via an oil bath on the unloaded side of the drive. This all has implications for the characteristics of the lubricant.
The lubrication of high load, slow moving conveyor chains may share some challenges with leaf chain lubrication and so research on these can offer some good suggestions.
When discussing their requirements with an expert lubrication company, customers should be very clear on the challenges of their specific application.
For assistance on this and any other leaf chain maintenance topics, feel free to get in touch.