Repointing lives or dies on how cleanly the old mortar comes out. The MK Diamond MK-404DT 8-inch (203mm) Supreme Grade tuck point blade is built for that step: a .375-inch wide diamond blade on a 7/8-inch to 5/8-inch arbor, sized to rake a standard mortar joint to depth in a single pass. It is aimed at masons, restoration contractors and property maintenance crews working through brick and block elevations where the brick is sound and the mortar is not.
Use cases
- Raking out failed or weathered mortar joints ahead of repointing brick and block walls
- Chimney, parapet and retaining wall repair where joints have eroded but the units are sound
- Grout and joint repair on concrete and masonry, including control joint cleanout
- Cleaning old mortar, adhesive and residue off concrete before a patch or overlay
- Removing sealant beds and failed joint filler prior to resealing
Why width is the whole point
A cutting blade is built thin so it removes as little material as possible. A tuck point blade is built thick for the opposite reason. At .375-inch this blade is close to the width of the mortar joint itself, so the joint is cleared to depth in one pass and the channel left behind has clean, parallel sides for the fresh mortar to key into. Trying the same job with a thin blade means multiple overlapping passes, a rough channel and far more time on the ladder.
Segments stand 10mm tall and are laser welded to the core, which is what lets the blade take the heat that mortar removal generates. Tuck pointing runs hot: the blade is buried in the joint with limited air around it, and the work is usually continuous rather than in short cuts. A laser-welded bond and a core that sheds heat between segments is what keeps that from becoming a problem.
Two things worth saying plainly. First, this is a mortar removal tool, not a cutting blade, so do not expect it to substitute for one. Second, tuck pointing is among the dustiest tasks in masonry and it puts that dust directly in the operator's breathing zone. Run a dust shroud and vacuum rated for the job.
Specifications
- Manufacturer: MK Diamond Products
- Model: MK-404DT
- Part number: 150663
- Diameter: 8-inch (203mm)
- Width: .375-inch
- Arbor: 7/8-inch to 5/8-inch
- Segment height: 10mm
- Segment attachment: Laser welded
- Tool compatibility: Angle grinders, circular saws and tuck pointers rated for an 8-inch blade
- Application: Mortar removal, grout repair and concrete cleaning
- Grade: Supreme Grade
Frequently asked questions
Why is a tuck point blade so much thicker than a cutting blade?
Because it is not making a cut, it is removing a joint. The .375-inch width matches a raked mortar joint so one pass clears it to depth, where a thin cutting blade would need several overlapping passes and would leave a ragged channel for the new mortar to key into.
Will it damage the brick either side of the joint?
Not if the blade is guided. Most joint damage comes from the grinder wandering, not from the blade. Work at a steady depth, keep the blade square in the joint, and on soft historic brick consider hand-raking instead. Sound modern brick and dense block tolerate grinder work well.
How deep should I rake the joint before repointing?
Common masonry practice is to remove mortar to roughly two to two and a half times the joint width so the new mortar has enough depth to bond and will not simply skin over and fall out. Follow the mortar manufacturer's specification and any preservation requirements on historic work.
What does this blade mount on?
MK lists tuck point blades for use with angle grinders, circular saws and tuck pointers. This part number is the 8-inch version with a 7/8-inch to 5/8-inch arbor, so check that your tool is rated for an 8-inch blade and that its spindle matches before mounting it.
Is dust control necessary for tuck pointing?
Yes, and more so than for ordinary cutting. Grinding out mortar generates a large volume of respirable crystalline silica in a confined spot, usually at head height with the operator right on top of it. Use a shroud and vacuum rated for the work and follow the silica rules on your site.
Discount Cleaning Products is an authorized MK Diamond dealer. Our US-based team works with these blades and saws every day, so if you are unsure which diameter, kerf or arbor suits your saw, call or email before you order and we will match the part to the machine. Orders are backed by the manufacturer warranty and by support that stays reachable after the sale.
