An 18 inch blade on a walk-behind saw buys depth, and depth is usually what decides whether a slab job takes one pass or three. The MK-500 in this size gives roughly six inches of cutting depth on a typical flat saw, which covers most residential and light commercial slabs in a single pass. It keeps the thin .125 inch kerf, so it is still removing a narrow ribbon of concrete rather than fighting the slab, and MK bonds it as the standard grade for contractors who saw regularly but do not need a production blade.
Built for
- Full-depth single-pass cuts on residential and light commercial slabs
- Driveway, sidewalk and patio removal cuts
- Trenching layout cuts for utility and plumbing runs
- Walk-behind flat saws in the 5 to 12 hp range
- Demolition perimeter cuts where a clean edge saves patch work
Specifications
- Model: MK Diamond MK-500, Standard grade for cured concrete
- Diameter: 18 inch (450 mm)
- Kerf (blade width): .125 inch
- Arbor: 1 inch
- Segment height: 10 mm
- Rim type: segmented, laser welded
- Cutting method: wet cutting only
- Published horsepower range for the MK-500 line: 5 to 12 hp
- MK Diamond part number: 128959
How to choose between grades
MK publishes its cured-concrete contractor blades in tiers that differ on segment height and the horsepower they are bonded for, not on cosmetics. The MK-500 standard grade carries a 10 mm segment and is rated 5 to 12 hp. The MK-505 premium grade carries a 12 mm segment and is rated 8 to 20 hp. Taller segment means more diamond to consume before the blade is spent, and the higher horsepower rating means the bond is built to survive the feed rate a bigger saw can push. Putting a premium blade on an underpowered saw will not make it cut faster, and putting a standard blade on a 20 hp saw will simply wear it out sooner. Match the blade to the saw first, then to the material.
Safe operation
This is a wet-cutting blade and it must be run with a continuous water feed. Running a wet blade dry is the single most common cause of segment loss, core warping and a scrapped blade, and it also puts respirable crystalline silica into the air. Water does two jobs at once: it carries heat out of the core and it knocks the dust down at the cut. Confirm your saw's arbor matches the blade before mounting, seat the blade flat against the flange, and never exceed the maximum operating speed stamped on the blade.
Frequently asked questions
How deep will an 18 inch blade actually cut?
Roughly six inches on a typical walk-behind flat saw, once you subtract the arbor, flange and guard clearance. Check your saw's published maximum depth for an 18 inch blade rather than assuming half the diameter.
Should I step up to the MK-505 in this size?
Only if your saw is bigger than 12 hp. MK publishes the MK-500 for 5 to 12 hp and the MK-505 for 8 to 20 hp with a taller 12 mm segment. On a mid-size walk-behind the MK-500 is the matched blade.
Can I cut asphalt with it?
Not well. This is a cured-concrete bond. Asphalt is soft and abrasive, and it will load and wear a concrete bond quickly. MK publishes separate asphalt blades for that.
Does an 18 inch blade need more water than a 14 inch?
Yes. More rim in the cut means more heat and more slurry. Make sure both sides of the blade are getting water, not just one.
Discount Cleaning Products is an authorized MK Diamond dealer. We stock the contractor blade lines rather than drop-shipping whatever a marketplace listing happens to carry, so the part number you order is the part number MK prints in its own catalog. Our US-based team can confirm arbor size, kerf and horsepower fit against your saw before you buy, and can help you match bond hardness to the aggregate you are actually cutting.
