Sawing a cured slab is not the same job as sawing green concrete, and the plate you mount decides whether the shift runs clean or turns into a string of blade changes. The MK Diamond MK-505 20-inch x .140-inch x 1-inch is MK Diamond's premium-grade wet-cutting segmented blade for cured concrete, and part number 135301 is the 20-inch (508 mm) diameter at a .140-inch kerf on a 1-inch arbor. It is built for the concrete cutting contractor, demolition crew, or municipal maintenance shop running a walk-behind flat saw on hardened concrete.
Use cases
- Full-depth slab cuts for demolition, removal and replacement panels
- Roadway, bridge deck and parking structure joint work on hardened concrete
- Trenching a cured floor for new plumbing, conduit or drain runs
- Expansion and control joint widening on existing pavement
- Squaring openings for doorways, equipment pads and pits in a finished slab
Where this size fits
MK lists a single kerf at this diameter, so there is no width decision to make: the .140-inch plate is the 20-inch MK-505. A kerf in this range is thin enough to keep engine load down and fast enough for production joint work, while still carrying the core stiffness a flat saw needs.
The MK-505 sits in the middle of MK's three-tier cured-concrete range (MK-500 standard, MK-505 premium, MK-525 supreme). Its 12 mm segment is taller than the 10 mm segment on the standard MK-500, so there is more diamond to consume before the blade is finished, and its 8 to 20 hp band puts it on bigger saws than the 5 to 12 hp MK-500.
Matching the blade to the slab
MK Diamond's own cured-concrete application chart rates the premium-grade MK-505 Better on cured concrete and Better on medium-hard aggregate with non-abrasive sand. MK does not recommend it for hard aggregate or for abrasive-sand mixes, where the supreme-grade MK-525 is the rated choice.
Aggregate is what actually wears a blade, not the concrete around it, so the mix in your slab matters more than the psi on the spec sheet. If you are cutting hard aggregate, or sand that is noticeably abrasive, step up the grade rather than pushing this one and paying for it in segment life.
Specifications
- Model: MK Diamond MK-505, premium grade for cured concrete
- MK part number: 135301
- Diameter: 20 inches (508 mm)
- Width (kerf): .140 inch
- Arbor: 1-inch
- Segment (rim) height: 12 mm
- Horsepower range: 8 to 20 hp
- Construction: laser welded, segmented rim
- Cutting method: wet only
Getting the most out of it
MK's published cutting guidelines are worth following, because most short blade lives trace back to the saw rather than the steel. Keep water volume at roughly 4.5 to 6 gallons per minute and split evenly on both sides of the blade. Seat the blade squarely against the flange so it runs true, since a bad seat produces lopsided wear and can burn the arbor. Let the blade do the cutting instead of leaning on it, as excess pressure glazes the diamond and stresses the core. And keep the blade out of the sub-base once you are through the slab, because sand in the base is abrasive and will wear the steel core and the segments faster than the concrete ever did.
Frequently asked questions
Will this blade cut green concrete as well as cured concrete?
It is built and rated for cured concrete. Green concrete is soft and abrasive and chews through a cured-concrete bond quickly, so MK publishes a separate green-concrete blade range for that work. Using a cured-concrete blade on green slab will cost you segment life.
What horsepower saw does the MK-505 need?
MK publishes a 8 to 20 hp horsepower range for the MK-505 line. Lower-horsepower saws deliver less torque, and MK notes that low-horsepower machines may need a softer bond to compensate.
How fast should the blade turn?
MK's cutting guidelines put most diamond blades between 9,500 and 11,500 surface feet per minute. At 20 inches that works out to roughly 1,810 to 2,200 rpm. Always confirm the maximum safe rpm printed on the blade and in your saw's manual before mounting.
Can it be run dry?
No. This is a wet-cutting blade. MK calls for adequate water on both sides of the blade at roughly 4.5 to 6 gallons per minute, at volume rather than high pressure. Running a wet blade dry overheats the core and risks losing segments.
Does it cut rebar?
Reinforced slabs are normal work for a segmented flat-saw blade, and steel in the cut is expected. Rebar is hard on diamond, so keep the water flowing and let the blade feed itself rather than forcing it.
Discount Cleaning Products is an authorized MK Diamond dealer, and we stock the MK-500, MK-505 and MK-525 cured-concrete ranges in the full diameter and kerf spread so you can match the plate to the slab instead of settling for whatever is on the shelf. Our US-based staff can help you confirm diameter, kerf and arbor against your saw before you order, and we support the products we sell after the sale.
