The most common mistake contractors and homeowners make when using tuck point blades  is “over-cutting.” This happens when the diamond blade travels beyond the mortar joint and slices into the top or bottom of the brick. These scars, often called “shiners” or “over-cuts,” are permanent. They weaken the masonry and create an amateur look that is nearly impossible to hide with new mortar.

To protect the building’s envelope and your reputation, you need to master the physics of the tuck point blade. This guide covers the techniques, tools, and mental prep required to remove mortar without leaving marks on the brick.

Understanding the “Arc of the Blade”

To stop over-cutting, you must first understand the geometry of the tool. A 4-inch or 5-inch tuck point blade is a circle. When you plunge a circular blade into a flat surface, the point where the blade enters the wall is not the same as the point where it reaches full depth.

Because of the curve (the arc), the blade is actually cutting much further along the surface than it is at the back of the joint. If you run the blade until the center of the hub reaches the end of a horizontal joint, the outer edge of the blade has already sliced two inches into the vertical brick.

The “Safety Buffer” Rule

Always stop your forward momentum at least two inches before you reach a vertical head joint. You will finish these corners later using a different method. Think of the tuck point blade as a high-speed freight train; it needs a braking distance. If you try to cut right to the edge, the RPMs and the centrifugal force of the grinder will almost certainly cause the blade to jump or “climb” out of the joint, scarring the brick face above.

The “Plunge and Pull” Method

Most beginners try to push the grinder forward like they are using a circular saw on wood. This is a recipe for losing control. For maximum precision, professionals use the Plunge and Pull technique.

1. Always Use Eye and Ear Protection
2. Set Your Stance: Stand with your feet shoulder-width apart. Hold the angle grinder with both hands, never one-handed.
3. The Initial Plunge: Start in the middle of a horizontal joint, away from any vertical intersections. Bring the blade up to full speed before touching the wall. Slowly plunge the blade into the mortar until you reach the desired depth (usually 1/2 inch to 3/4 inch).
4. The Pull Stroke: Instead of pushing the grinder away from your body, pull it toward you. Pulling provides much better resistance against the rotation of the blade. This prevents the tool from walking or skipping across the brick.
5. Watch the Leading Edge: As you pull the grinder toward a corner, keep your eyes fixed on the top edge of the blade. As soon as you get within two inches of a cross-joint, stop.

Navigating the T-Joints and Corners

The “T-joint” (where a vertical head joint meets a horizontal bed joint) is where most over-cutting happens. This is the danger zone.

To handle these areas safely, change your angle of approach. Instead of keeping the blade buried deep, lift the back of the grinder so only the bottom nose of the blade is working. This reduces the surface contact area and lets you nibble away at the mortar closer to the brick edge.

However, even with the best technique, a 5-inch blade is often too large to get into tight corners without risk. This is where your equipment choice becomes vital.

Use the Right Tool for the Finish

If you encounter a particularly tight corner or a historical brick that is soft and prone to chipping, put the grinder down. Use a hammer and a narrow cape chisel to pop out the last inch of mortar. It takes an extra sixty seconds, but it saves you the hours of labor required to replace a damaged brick.

Equipment Matters: Why Blade Quality Prevents Damage

A cheap, wobbly blade is the enemy of precision. If your tuck point blade has any run-out (side-to-side vibration), it will widen the cut and chip the edges of the brick (arris).

At Diamond Blade Planet, our tuck point blades are engineered with reinforced cores to reduce flexing. When the core is stiff, the blade stays where you point it.

Choosing the Right Width

Using a blade that is too wide for the joint is a guaranteed way to damage the brick. If your mortar joint is 3/8 inch, do not use a 3/8-inch blade. You need a bit of wiggle room.

• For a 3/8″ joint, use a 1/4″ tuck point blade.
• This allows you to make a pass through the center and then clean up the top and bottom edges with secondary, lighter passes.
• This two-pass method gives you more control over the height of the cut and helps avoid grinding away the baked crust of the brick, which is its most protective layer.

Managing Dust for Better Visibility

You cannot avoid over-cutting if you cannot see what you are cutting. Tuck pointing creates a massive volume of fine silica dust. Within seconds, the joint is obscured by a grey cloud.

If you are cutting blind, you are guessing where the blade is. To prevent damage, use a dust shroud attached to a high-CFM vacuum. A clear or semi-transparent dust shroud helps you see the contact point while removing most of the debris. If dust build-up is still too heavy, stop, let the air clear, and brush out the joint before continuing.

Lighting the Way

Many masonry projects happen on scaffolding under shadows or in late-afternoon light. Poor lighting is a common cause of over-cutting. If you cannot see the distinction between the grey mortar and the red brick, you will eventually make a mistake.

Set up work lights that rake across the wall. This side-lighting creates shadows in the joints, making the depth and the boundaries of the mortar easier to see.

Summary Checklist for Damage-Free Cutting

• Mark Your Stops: Use chalk to mark stop points 2 inches away from every corner.
• Pull, Don’t Push: Pull the grinder toward your body for better control.
• Check Your Blade: Ensure the blade is seated correctly on the arbor and has no wobble.
• Depth Control: Use a grinder with a depth-gauge attachment if you struggle to maintain a consistent plunge.
• Clear the View: Use a vacuum shroud to keep your line of sight clear of silica dust.

Protect the Brick, Save the Project

The goal of mortar removal is to create a clean, square U-shaped channel for the new mortar to bond to. It is not a race. Slow down at the intersections and use a stable blade so the only thing being removed is the old mortar, not the brick itself.

Ready to start your restoration project? Check out our professional-grade
Tuck Point Blades to get the precision you need for a damage-free finish.