Short answer
The wrong grease shows up not as a fault but as a result: bushings finish earlier than expected, deep scores appear on the tool shank, the grease coming out of the point is thin and clear or, on the contrary, burnt and hardened, and fresh grease blackens and picks up rock dust within hours. All of these have one cause: the contact face of a breaker works under impact and high temperature, and general purpose grease cannot leave a lasting film in those conditions. Where the grease is wrong, shortening the interval does not fix the problem, it only repeats it more often.
What a breaker grease has to do
In a breaker, grease does more than separate two metal faces; it has to stay on that face under impact and at the same time keep incoming rock dust out. General purpose grease thins as it heats, runs, and the film breaks; the moment the film breaks, shank and bushing are in direct contact.
The SolidLube grease HKM uses is a product made for those conditions, and the maker publishes its values: NLGI 2 consistency, a 250°C dropping point, a wide working temperature range and around 15 per cent solid lubricant content. The solid content is what stays on the surface and carries the contact once the fluid film breaks, and in an impact application that is what decides the outcome.
We give those values here not as a threshold but to show what to ask: where the data sheet of the grease you hold does not state a dropping point, an NLGI class and a solid lubricant content, you have no information about whether that grease suits a breaker.
Reading the signs
- Thin, clear, runny grease coming out of the point: the grease has thinned under heat and is not staying on the contact face.
- Burnt, hardened, crusted grease: the temperature rating is insufficient and the grease has cooked.
- Fresh grease blackening within hours with rock dust in it: the film cannot keep dust out and abrasive is getting in.
- Deep longitudinal scores on the tool shank: the lubricating film has broken and abrasive has been working in between.
- Bushing dimension growing faster than expected: the grease is either wrong or insufficient.
- The same result on every machine on the same site with the same grease: this is no longer a machine problem but a grease problem.
The cost of misreading the sign
The first reflex on seeing these signs is usually "let us grease more often". Increasing the frequency with the wrong grease raises consumption without building the film, and it also masks the case where the real cause is technique or interval rather than the grease. Look at the data sheet first, then at greasing technique, and at the interval last.
Three common wrong choices
- Feeding the machine's multipurpose grease to the breaker as well: the commonest mistake. The same grease can be right on the boom pins and wrong on the breaker tool.
- Choosing a "thicker" grease because the consistency is higher: consistency on its own is not durability; what decides it is temperature rating and solid lubricant content.
- Running different brands on top of each other: where the soap types are incompatible, the mixture thins or separates. When changing grease, purge out as much of the old grease as you can.
Do and don’t
Do
- Ask for the grease data sheet; it must state dropping point, NLGI class and solid content.
- Keep a separate grease for the breaker; do not mix it with the machine's general grease.
- Apply grease with the tool pressed against the ground; where the technique is wrong, the right grease still fails.
- Look at the colour and content of the old grease coming out; half the diagnosis is there.
- Purge out as much of the old grease as possible when changing product.
Don't
- Do not try to cure the wrong grease by "greasing more often".
- Do not deliberately mix different grease types.
- Do not use a grease of unknown dropping point in a breaker.
- Do not accept burnt grease as normal; that temperature is itself the sign of a problem.
- Do not treat grease consumption alone as a measure of success; what matters is that the film holds.
What HKM uses
Grease made for breakers
SolidLube grease cartridges are developed for impact applications: NLGI 2 consistency, a 250°C dropping point and around 15 per cent solid lubricant content. The solid content stays on the contact face even where the fluid film thins under heat. The cartridge can be used with an automatic lubrication station or by hand.
SolidLube grease cartridges(solid-lube.com)Where the grease is right and the problem continues
Where the grease is technically right and the signs persist, the next two suspects are technique and interval. Greasing done with the tool in the air never reaches the contact face however good the grease is; the gap between shank and bushing is open and the grease leaves through it.
On the interval side, what decides it is the site: in a dusty, abrasive environment the same breaker needs greasing more often than on a clean site. That is why no fixed hour figure would be right; you calibrate the interval on your own site by looking at the grease coming out.