Floor Saws

Concrete shrinks as it cures and gives up water. A slab held down by friction against the sub-base cannot shrink freely, so stress builds — and at some point it cracks. That cannot be prevented; the only thing you decide is where.

A sawn joint weakens the section along a chosen line, so the crack forms underneath it, straight and out of sight. There is one condition: the cut has to exist before stress reaches the concrete's tensile strength. A few hours late and it achieves nothing — the slab has already cracked on its own terms, usually diagonally and through the middle of the bay.

That is where the two cutting technologies come from, and why both sit in this category.

Early entry — onto concrete that is still green

The TAS 150 is an early entry saw: it goes onto the slab right after power floating, once the concrete carries the machine but is still soft enough that the blade does not have to fracture it. The cut is shallow — 30 mm — and that is enough, because the point is to weaken the section, not to sever the slab.

Green concrete has one weakness: the cut edge wants to ravel. That is what the skid plate fitted alongside the blade is for — it holds the material down on both sides of the cut line, so the edge stays straight instead of ragged. Without it the technique does not work, which is why blade and skid plate are also sold as a kit in diamond blades.

Wet cutting — material already hardened

The TFS 500 and TFS 600 Drive work on cured concrete and asphalt. They cut deeper — 180 and 220 mm — because their job often is to sever the slab: for a service penetration, to lift out a section of surfacing, for road repair, or to widen an existing joint before sealing.

Cutting depth is always well under the blade radius, because the arbor, flanges and guard take up part of the diameter. On these machines it works out at roughly one third of the diameter: a 500 mm blade gives 180 mm, a 600 mm blade gives 220 mm. Check that figure first, because a saw with too small a blade will not sever the slab however much power it has.

In sawing, feed rate decides quality. Too fast and the blade binds, segments tear off and the line wanders; too slow and the segment glazes over and stops cutting. On a pushed machine that rate is held by a person, and it gets worse as the shift goes on.

The TFS 600 Drive has an electric 24 V travel drive with a potentiometer for stepless speed, fed by two batteries and charged in use from a 35 A alternator. The operator sets a feed to suit the material and the machine keeps it to the end of the cut. At 190 kg it is also the only way to track straight.

Two cutting guides, front and rear, and hydraulically assisted depth adjustment with a lock every quarter turn serve the same purpose. On the TFS 500 the equivalent is damped adjustment with a scale calibrated for 350–500 mm blades, so the operator reads the depth instead of estimating it.

A diamond segment cuts because its metal matrix wears at a controlled rate and keeps exposing fresh crystals. Without cooling the matrix softens, crystals are lost before they have done any work, and the heated blade goes out of true and starts to wander. Water removes heat and flushes slurry out of the kerf — both at once.

So the TFS 500 and TFS 600 feed water to both sides of the blade from 35 and 37 l tanks. That is a run's worth, not a day's — on longer stretches you plan a bowser or a mains connection.

The TAS 150 works the other way: it cuts dry, through a 50 mm dust port. On a fresh slab water would be a mistake — it would soften the surface that has just been floated. The dust does have to be captured at source, because respirable crystalline silica from concrete is a carcinogen rather than just dirt. Extractors for this work are in industrial vacuum cleaners.

Start from what you cut, and when

A fresh slab on the day of the pour means the TAS 150 and nothing else — the other machines are too heavy to drive onto it and cut deeper than the stage requires. Hardened surfacing, asphalt, lifting out a section or widening an old joint means the TFS 500 or TFS 600. These are not competing machines; they are two different stages.

Work out depth before power

Depth follows blade diameter, not engine size: 180 mm on a 500 mm blade, 220 mm on a 600 mm blade. If the slab is 200 mm and has to be severed, the TFS 500 will not do it no matter how strong its engine is. Power affects the rate of cut and whether the machine holds revs in hard aggregate — not how far the blade reaches.

Check how the machine gets to site

The 38.5 kg TAS 150 travels in a car once the handle is folded. The 98 kg TFS 500 needs a trailer, but has a central lifting hook, so it can be craned to an upper floor. The 190 kg TFS 600 means a plant trailer and a ramp — irrelevant on road works, decisive for a slab on the first floor of a building.

Match the blade to the material, not to the saw

The machine only dictates diameter and bore; whether the cut works at all depends on the segment bond matched to the material. Asphalt, block paving, sand-lime block and concrete are four different jobs for diamond — the full split is in diamond blades.

Blades for every one of these jobs — asphalt, block paving, Porotherm and sand-lime block, green and hard concrete — are in diamond blades, together with the early entry skid plate. The moment a slab is ready to be cut follows from the work described under power trowels. Dust from dry cutting is captured by industrial vacuum cleaners, and openings for services in a slab already cut are made with core drills.