Floor grinder maintenance: daily checks and wear parts

The routine below is taken from the operating instructions for PG 280, PG 400 and PG 450. The large machines PG 680 and PG 820 also have their own points for the grinding heads and the planetary drive, which are covered at the end.

Before you start

Carry out inspection and maintenance on level ground, with the motor stopped and the plug disconnected. Let the machine cool down before removing the diamond tools. The tools are very hot after use, and you must wear protective gloves.

The operating instructions also say that the diamond tools should be removed after each job, and that the machine should only be put in the service position on a level surface.

Cleaning and air vents

Clean the equipment at the end of the working day, but not with a pressure washer. For PG 680 and PG 820, the operating instructions warn against cleaning the machine with a water spray or similar.

Clear any blockages from all air vents. A blocked air intake reduces performance and can cause the motor to overheat.

Power cable and extension cable

Check that the power cable and extension cable are in good condition and undamaged. If the power cable is damaged, the machine must not be used, and the repair must be left to an approved service centre.

The extension cable also affects operation. If the machine stops during start-up, the troubleshooting section says that the correct supply voltage is needed for good motor performance, and that extension cables that are too long or undersized reduce motor power. If the motor is overloaded, the overload lamp lights up: wait two minutes and try again, and contact an approved service workshop if that does not help. On PG 280 and PG 400, the troubleshooting section also says to press the overload protection. There is more on power supply in the guide on power on the building site.

The brush skirt

Check that the brush skirt is intact, clean and undamaged, and that it touches the floor. The machine must only be started with the brush skirt fitted, and it must sit tight against the floor, especially when working on a dry surface. Replace a damaged brush skirt.

The tool holder and the rubber cylinders

The condition of the tool holder is crucial for both performance and safety. Remove the tool plate, examine the holder for damage and check the wear on the rubber cylinders. Replace the cylinders as needed.

PG 450 has three grinding discs, and its operating instructions say that the holders should be replaced or repaired as needed.

If the machine makes sudden jerky movements, the troubleshooting section says to check that all the diamond tools are correctly fitted and are the same height.

PG 680 and PG 820: head locks and grinding heads

PG 680 and PG 820 have a planetary head and grinding heads that are each driven by their own motor. The general inspection in the operating instructions has three points:

• The cable and extension cable should be intact and in good condition
• Nuts and bolts should be tight
• The head locks should be tight. If necessary, tighten them and refit them with thread locker; Husqvarna suggests Loctite 680

The spring steel in the grinding heads

The grinding heads on PG 680 and PG 820 have springs made of spring steel. Over time the steel fatigues, and the “fingers” start to break off. This causes uneven movement in the grinding heads and vibration when the machine is running.

The operating instructions recommend routine checks and state that the service life of the grinding heads can vary between 6 and 12 months, depending on use. The springs can be replaced without discarding the grinding head.

If a PG 680 or PG 820 leaves an irregular scratch pattern, the troubleshooting section lists four things to look for:

• Diamonds that are not correctly fitted, are of different heights or are mixed. All segments should have the same grit and bond
• Head locks that are loose or missing
• Grinding heads that are worn or damaged, with broken parts or too much play
• Resin tools that are mixed or contaminated. All resin tools should have the same grit and bond and be clean

The planetary drive must not be lubricated

On PG 680 and PG 820, the drive wheel and chain ring that drive the planetary head are a dry system. It must not be lubricated, so that dust that gets in can fall out again. Lubrication makes dust build up in the chain ring and greatly shortens the life of both the ring and the drive wheel.

A planetary seal is there to keep the dust out. If you lift off the motor and gear unit and find a 5–6 mm layer of dust under the cover, the operating instructions say it is probably time to remove the machine cover and check the seal.

The belt and bearings are workshop jobs

On PG 680 and PG 820, the grinding discs are driven by the large motor via an internal belt enclosed inside the machine. It needs no maintenance until a major service with belt and bearing replacement, which typically comes after 12–36 months of operation. Demanding use can bring it forward, and the machine must then go to an authorised service workshop.

The user should only carry out the maintenance described in the operating instructions. More extensive work must be done by an authorised service workshop.

Storage and transport

PG 280 and PG 400 should be stored indoors, and all three, including PG 450, in a dry, frost-free, locked area. PG 680 and PG 820 should be kept dry, in a lockable room. For PG 680 and PG 820, transporting the machine with a set of diamonds fitted is recommended, to protect the locking mechanism for the diamond plates.

Service and parts

Sigurd Stave Maskin AS is Kiwa-verified and certified to carry out annual inspections, and has mobile service technicians based in Oslo and Bergen. The workshop can be reached on +47 969 13 856 during the day, and parts for the machines we sell can be ordered via the spare parts page.

The segments are covered in the guide on grinding segments, and there is a separate guide on dust extractor maintenance.