Diamond cutting blades for cutting stone

Marble and limestone are mainly cut with electroplated diamond cutting blades. Sintered diamond cutting blades are suitable for sandstone and granite.

Galvanic diamond cutting blades

With electroplated diamond cutting blades, the diamond particles are on the surface of the cutting blade, which can be seen very clearly. Once the diamond particles have become blunt, they cannot be resharpened and the cutting disc has lost its cutting power. However, the advantage of electroplated diamond cutting blades is that the diamond particles are much more concentrated than e.g. sintered cutting blades, so that the removal in softer rock is much greater and faster.

Electroplated diamond cutting blades are very suitable for softer stones up to harder marble (approx. 5 on the Mohs scale) and also for some types of granite. It is important that the stones contain only small abrasive parts such as quartz, otherwise the cutting disc will quickly become blunt. Sandstone as well as very hard stone should not be cut with an electroplated diamond cutting blade if you want to protect the cutting blade and use it as long as possible.

Sintered diamond cutting blades

With sintered diamond cutting blades, the diamond particles are embedded in the metal. Due to the abrasion of the metal during cutting, new diamond particles keep coming to the surface so that the cutting disc is always sharp or keeps resharpening itself, which leads to an optimal cutting result. This happens especially with medium to highly abrasive types of stone. Compared to galvanic cut-off wheels, sintered cut-off wheels contain more diamond particles, but they are distributed differently.

For cutting highly abrasive stone (e.g. sandstone), a sintered diamond cutting blade should have a much harder bond for a long service life than for medium abrasive stone. With less abrasive stone (e.g. hard marble, some types of granite, diabase), it can happen that a sintered cut-off wheel becomes blunt because the abrasion is too low and thus no new, sharp diamond particles come to the surface. It then helps to 'roughen' the surface of the cut-off wheel on a highly abrasive stone such as sandstone to restore the sharpness for optimal cutting results.

Watch the cutting speed

When using cut-off wheels on the angle grinder, pay attention to the correct speed: When using cut-off wheels, speeds that are too low will leave marks; speeds that are too high can damage the tool. Therefore, pay attention to the manufacturer's specifications.

The cutting speed is given in metres per second (m/s). As the diameter increases and the number of revolutions remains the same, the cutting speed increases. This can be calculated quite easily, e.g.:

A cut-off wheel of 125 mm diameter has a cutting speed of (125 x 6,000)  : 20,000 = 37.5 m/s.