Checked 22 September 2026
Lapidary saw blades and coolant
A replacement saw blade must fit the shaft, reach the stone and be rated for the saw's speed. Its cutting edge and the liquid used to cool it affect the cut. Check the width of the cut and the saw manual before ordering.
Read more than the diameter
A blade listing can name its outside diameter, arbor hole, core thickness and kerf. The core is the metal plate; the kerf is the width of the cut made by the diamond rim. Kerf usually exceeds core thickness. The blade also has a maximum permitted speed. Record all five details from the blade and saw manual before ordering.
For example, Hi-Tech's six-inch trim saw has a 5/8-inch arbor. Its listed notched blade has a .012-inch core and .015-inch kerf, while its listed sintered blade has a .015-inch core and .023-inch kerf. Other blades of either type can have different dimensions.
Match the blade to the material and feed
Manufacturers offer electroplated, notched-rim and sintered diamond blades for different work. A thin blade saves costly rough, but it can wander or wear if forced or used outside its intended work. A thicker blade removes more material and may withstand heavier cutting. Hi-Tech supplies different six-inch blades for different materials and publishes a manual for each machine. Use the blade maker's material and speed guidance with the saw maker's instructions.
A ten-inch machine may be called a trim saw or slab saw. Its blade choice still depends on arbor, clearance, material and feed. The saw guide compares four current configurations. Do not use a reducer or modified arbor unless the blade and saw makers approve the arrangement.
Use the coolant your saw and blade allow
Coolant carries heat and cutting debris away from the blade. Hi-Tech says its blades work with water or oil. Its FAQ finds water better in its 4-, 5- and 6-inch trim saws and oil better in its 10-inch saw, and asks owners to weigh the material and blade as well. That advice covers Hi-Tech machines only.
Hi-Tech tells owners to fill the reservoir until the bottom of the blade sits about 1/8 inch deep in the coolant; heavy spray means the level is too high. With water, it suggests an additive for heat-sensitive stone such as tourmaline. Another saw may need a different level, so use its manual. Before adding an oil or concentrate, read the product label and the saw and blade instructions, including ventilation and disposal. Keep electrical connections out of the splash zone.
Before a replacement goes on the shaft
- Read the saw model and motor plate. Record arbor size, guard clearance and speed.
- Read the old blade's diameter, core, kerf, diamond-rim type and rotation marking.
- Confirm the new blade's permitted material, speed, coolant and mounting with its maker.
- Inspect the flanges, guard and coolant route before running the saw. Follow the manual's installation procedure.
One blade name can cover several sizes. Johnson Brothers' 2010 catalogue listed six-inch Pro-Slicer blades with .006, .012 and .025-inch cores, each with a 1/2- or 5/8-inch arbor. Order by all four measurements, not by name and diameter: a blade of the right diameter can still fail the arbor, guard or speed checks.