Diamond cutting blades provide a range of advantages over standard steel cutting blades, especially when used in a construction capacity or in cutting through very tough materials. Diamond saw blades are conventionally used to cut materials ranging from asphalt to marble, soapstone, brick, tile granite and mortar, where a steel blade would dull and fail to cut.
However, diamond circular saw blades are not normally required when cutting through wood, cardboard or other comparatively soft materials. In these cases, a standard steel blade will suffice, and these blade types are much more commonly seen in these situations.
The real strengths of a diamond blade can be found in its unique component – diamond – and in the way that this diamond is utilised. The manufacture of diamond blades uses synthetic diamonds, rather than naturally-occurring ones dug out of the ground, and relies on the diamond pieces acting as thousands of small, sharp “teeth” which are partially exposed on the cutting surfaces of the blade.
At speed, these diamond shards tear through even stone and metal, with the steel body of the blade actually forming no more than a carrier and driver for these diamond pieces. As the diamonds wear down with repeated or prolonged use, the metal and bonding methods used on the diamonds also wear themselves down, revealing new, sharp diamond teeth underneath. This process is similar to a shark’s jaw, where old, blunted teeth simply fall away and new ones cycle up to replace them, extremely sharp and ready to cut.
This is one of the primary strengths of a diamond-edged blade, providing longevity and incredible cutting power even when cutting through the hardest materials. It should be noted, however, that if a diamond blade is allowed to become too hot or is made to cut into a material too hard for its rating, the blade may suddenly cease cutting and become “dull” due to the soft metal bond which holds the diamonds in place giving out prematurely or melting and covering the diamond edges. As these teeth are the real cutting power of the diamond blade, it is no surprise that this will render the blade useless.
If this happens, the blade will need to be “dressed” or re-sharpened, making it able to cut again. A dull diamond blade may have completely worn out, in which case the rim will be entirely gone and you will need a new blade, but if you can still see some on the edge of your blunt blade, it can probably be rectified with proper dressing. Simply make a cut as normal into a material like firebrick or asphalt to abrade the steel away from the new diamonds, restoring the cutting power of the blade.
This is not a problem that occurs with non-diamond blades, but in similar circumstances a steel blade would likely just dull and require professional re-sharpening or complete replacement, so a diamond blade is still likely to be your best bet.