Turbo Diamond Cup Wheel for Concrete
Single-row turbo cup wheel
The second pass on the edge
A turbo diamond cup wheel is a single-row grinding disc with swept, continuous segments. It cuts more smoothly than a double-row wheel and is used for the second pass along walls and corners, taking out the coarse scratch so the ground edge matches the finish of the open floor.
A double row takes material off. A single row of swept turbo segments takes the scratch out. They are the same size, they fit the same machine, and a crew that owns only one of them is using the wrong one half the time.
Twelve segments in a single ring, swept so the wheel feeds continuously instead of hammering. It is slower per pass and it leaves far less behind it.
Why the edge gets two passes
The open floor is ground by a planetary machine carrying nine heads, which is heavy enough and slow enough to leave an even plane. The perimeter is ground by one person leaning on a hand grinder, and a hand grinder cuts in whatever direction it is pushed.
The first pass is about speed and depth. The second is about taking the first pass’s own marks back out, so the border meets the open floor as one surface rather than two.
The same head, softer
A turbo profile keeps more of the segment in contact with the slab at any moment, so it cuts smoother and glazes less on hard concrete. It also wears faster, which is the trade and the reason it is a second head rather than the only one.
Without itA ground border that is flatter than the rest of the room but rougher, and it takes the coating differently; you read it as a halo round the walls once the floor is wet.
What to ask
Ask what the perimeter gets ground with and how many passes it gets. One head and one pass is the answer that leaves the halo.
Where it is used
Day 01 of the job, prep, on every system we lay: decorative epoxy, flake floors, urethane cement, quartz broadcast, heavy industrial and repairs & recoats.
Questions people ask
What is the difference between a turbo and a double-row cup wheel?
A double-row wheel has two rings of separate segments and removes material aggressively. A turbo wheel has one ring of swept segments that stay in contact with the concrete more of the time, so it cuts more smoothly and leaves a finer scratch, at the cost of wearing faster.
Why do the edges of an epoxy floor need two grinding passes?
A hand grinder cuts in whatever direction it is pushed, so the first, coarse pass leaves uneven marks. On a thin coating those marks show through. A finer second pass evens the edge out, so it takes the primer and resin the same way the rest of the floor does.
What does a halo round the walls of an epoxy floor mean?
A band that looks different from the middle of the floor, usually in raking light, means the edge was prepared differently from the open area: ground coarser, ground less, or not ground at all. It is a preparation mark, and it cannot be fixed without recoating.