Makita D-80640 Diamond Cup Wheel for Concrete, Turbo, Fine, 125x22.23 mm

Makita D-80640 Diamond Cup Wheel for Concrete, Turbo, Fine, 125x22.23 mm

Makita D-80640 is a diamond cup wheel with a diameter of 125 mm and a 22.23 mm bore. In the Makita catalogue the type is listed as an offset diamond wheel - an offset, cup-shaped body with a continuous corrugated Turbo diamond band wrapped around its rim. This is not a cutting disc: the cup removes material across an area - it levels poured concrete slabs and takes off formwork residue, cement, tile adhesive and paint.

Of the three grits Makita offers for this type of cup wheel, the D-80640 is the finest: the ROUGH - STANDARD - FINE scale on the box is marked at FINE. It is the wheel you reach for when the surface behind it will not be worked again, but rendered, tiled or painted straight away.

What it is for

Its job is levelling and cleaning up concrete and stone, not bulk removal. Typical tasks:

• smoothing poured concrete slabs and steps after the formwork comes off - seams, steps and overspill;
• taking off old cement, screed and tile adhesive from a floor or a wall;
• cleaning up concrete walls and columns before filler or waterproofing;
• working stone, brickwork and kerbs - chamfers, levelling to height;
• fine smoothing in corners and up to a wall.

Makita describes the shape as very stable, highly efficient and also suitable for corners. The stability comes from the wide bearing area: the cup sits flat instead of skipping the way a disc does when it stands on its thin rim alone.

The Turbo band - continuous and corrugated

The diamond band is continuous and corrugated (Turboband) - it is not made up of separate segments with gaps between them. The difference shows in two places. First, the finish is more even: on a segmented cup every segment leaves its own arc and the surface comes out ribbed, whereas a continuous band sweeps without a break. Second, vibration is lower, because the contact between grit and concrete never breaks.

The waves do the job the slots do on a segmented cup: they clear the dust and let air in, so the wheel does not choke and overheat. The body carries eight holes that feed air from the inside.

Makita gives the band dimensions as 15 mm high and 4.5 mm thick. That is the life of the wheel: it keeps working until the band is worn down to the body.

Why the machine needs SJS or a soft start

This is the one real restriction on this article, and Makita states it explicitly. The wheel is heavy - 505 g with its packaging, while an ordinary 125 mm cutting disc weighs several times less. Every time the machine starts, that mass has to be accelerated to working speed in a fraction of a second, and the shock goes straight into the gearbox.

That is why the manufacturer asks for an angle grinder with SJS, SJS II or a soft start. SJS (Super Joint System) is a mechanical clutch in the head of the machine that absorbs the shock; a soft start does the same electronically by running the motor up gradually. The SJS symbol is printed on the wheel's packaging as well. On a plain angle grinder with neither, the cup will still spin - but the gearbox pays for every start.

Which machines it fits

The 22.23 mm bore is standard for 125 mm angle grinders, so the wheel fits without an adapter. Makita lists the article for:

• 125 mm concrete planers - PC5001C and PC5010C;
• corded 125 mm angle grinders - 9565CR, 9565CVR, 9565HR, GA5021C, GA5040C01, GA5041C01, GA5090X01 through GA5095X01;
• cordless LXT 18 V - the DGA504 to DGA518 range;
• cordless XGT 40 V - GA005G, GA013G, GA016G, GA023G, GA026G, GA029G, GA032G, GA050G.

The maximum speed is 12,250 min^-1 and the maximum peripheral speed is 80 m/s. The speed is stamped on the hub and printed on the box; the peripheral speed, on the hub only. The machine's speed must not exceed them; standard 125 mm angle grinders stay below that limit.

The materials Makita rates it for

Makita publishes a rating on its own material scale. For the D-80640 it reads:

• Top rating (AA) - concrete, concrete block, kerbs and paving elements, cemented tile;
• Rating A - hard concrete, granite and gneiss; marble and unglazed tile; brick, aggregate block and clay tile; asphalt.

In short: ordinary concrete is its home ground; on the other materials it works, without that being its strength. It is not intended for metal, wood or plastic.

Technical specifications

Scope of supply

• 1 x Makita D-80640 diamond cup wheel, Ø125 x 22.23 mm, Turbo, fine grit - the box is marked x1
• No flanges or lock nut - the ones on the machine are used
• No dust-collecting shroud - bought separately if the machine has none
• No reducing ring - the bore is a fixed 22.23 mm

Working tips

Follow the arrow. The direction of rotation is stamped on the body. Fitted the wrong way round, the band does not cut properly and wears faster.

Do not lean on it. The cup works through its own weight and its speed. Pressing does not speed up removal - it heats the band, clogs it with dust and eats into its life. Guide the machine in even, overlapping passes.

Keep it flat. The cup should sit on the whole band at a shallow angle. Working on the edge leaves ring marks that then have to be smoothed out.

Think about the dust. Grinding concrete throws up fine silica dust that is bad for the lungs. Work with a dust-collecting shroud and a vacuum - which is why Makita also lists this wheel for the PC5001C and PC5010C concrete planers, where extraction is built in. A mask, goggles and gloves are a must.

Smaller size. The same Turbo band in fine grit is also available at 100 mm diameter with a 16 mm bore - article D-80628.

Questions and answers