Knowledge · Tool selection
A diamond tool is chosen in three steps: the machine sets the diameter, bore and power; the material sets the bond hardness, concentration and diamond grit size; the working conditions set the cooling and segment shape. The bond rule: the harder the material, the softer the bond – the more abrasive, the harder.
The key points in 30 seconds
With the machine: diameter, arbor bore and power follow from the saw. Only then are the bond and segment matched to the material – aggregate hardness, amount of rebar and abrasiveness. The segment shape comes last: straight, turbo or roof-top segment.
The bond is the metal matrix of the segment that holds the diamond grains. It should wear at the rate the diamonds go blunt – then it constantly exposes new, sharp grit. How to read bond hardness on a datasheet: bond, concentration, grit size.
It depends on the aggregate. Concrete with granite or basalt aggregate needs a soft bond, concrete with sand and abrasive gravel a harder one. Green concrete is very abrasive and also needs a hard bond. Details and an on-site aggregate test: concrete blade for granite aggregate.
Concentration is the amount of diamond in the segment. Higher concentration increases life and resistance when cutting rebar; lower speeds up cutting in soft and abrasive materials. Scale: C100 = 4.4 ct/cm³ – converting concentration to carats.
Large blades, reinforced concrete and core drilling in concrete – wet: water cools the segment and flushes out the debris. Dry cutting is done briefly, with tools designed for it, with dust extraction. For hand-held cut-off saws see cutting mode and silica dust.
Three parameters that decide whether a blade cuts fast and lasts.
How aggregate hardness changes bond selection.
Abrasiveness, core protection and the consequences of swapping tools.
Segment shape and starting the cut, cooling and debris removal.
300–400 mm diameters, 20 and 25.4 mm bores, dry and wet cutting.
Didn't find an answer?