The 18 inch MK-505 is what a concrete cutting contractor mounts when the pour is thick and the schedule is not forgiving. Eighteen inches of diameter gives roughly six inches of depth on a walk-behind flat saw, enough to take most commercial slabs in a single pass, and MK's premium bond with its 12 mm segment is built to survive doing that repeatedly on a saw in the 8 to 20 hp range. It keeps the thin .125 inch kerf, so the blade is still removing a narrow ribbon rather than fighting the full width of the slab.
Built for
- Full-depth single-pass cuts on thick commercial slabs
- Production pavement and roadway sawing on cured concrete
- Demolition perimeter cuts where a clean edge reduces patch work
- High-horsepower walk-behind flat saws running daily
- Trenching layout cuts for utility, plumbing and conduit runs
Specifications
- Model: MK Diamond MK-505, Premium grade for cured concrete
- Diameter: 18 inch (450 mm)
- Kerf (blade width): .125 inch
- Arbor: 1 inch
- Segment height: 12 mm
- Rim type: segmented, laser welded
- Cutting method: wet cutting only
- Published horsepower range for the MK-505 line: 8 to 20 hp
- MK Diamond part number: 129072
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 much depth does an 18 inch blade give me?
Roughly six inches on a typical walk-behind flat saw, after arbor, flange and guard clearance are subtracted. Check your saw's published maximum depth for an 18 inch blade rather than assuming half the diameter.
Why the MK-505 rather than the MK-500 in 18 inch?
Horsepower and segment height. The MK-505 is bonded for 8 to 20 hp with a 12 mm segment; the MK-500 is bonded for 5 to 12 hp with a 10 mm segment. If your saw is at the larger end, the premium blade is matched to it and will last meaningfully longer.
Does a larger blade need more water?
Yes. More rim is in the cut at any moment, which means more heat and more slurry to flush. Confirm water is reaching both sides of the blade, not just one.
Can I use it on green concrete or asphalt?
No. This is MK's cured-concrete bond. Green concrete and asphalt are abrasive in a way that wears a cured-concrete bond fast. MK publishes separate blades for both.
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.
