Rubi TX-1250 vs Sigma 3L Klick for Scoring 120cm Rectified Porcelain Cleanly

The Last 200mm of a Long Score

A 120cm score usually gives up in the final 15cm to 20cm before the plank edge. On the Rubi TX-1250, the chromed guide bars measure 25mm diameter and the machine ships with a separator base rated for tiles up to 22mm thick. The Sigma 3L Klick carries its scoring assembly on a single extruded bar and uses the click mechanism to lock the breaker foot before the snap.

Both designs bend under scoring pressure. Across a long plank, the deflection that matters appears as the wheel reaches the last part of the run and the score line starts to drift. Stated bar length only tells you whether the tile physically fits. Clean separation depends on wheel geometry, rail rigidity across the final 200mm, and how the fired body reacts to the wheel.

Rectified porcelain adds difficulty because the body is fired above 1200C and vitrified to below 0.5% water absorption under the ISO 10545-3 classification. The rectified edge is ground square after firing, which removes the slight radius left on a pressed edge. A score has to start a fracture plane through a face with almost no forgiveness at the perimeter.

If the wheel hops once during a 1200mm run, it leaves a visible witness mark. During the snap, the fracture follows the deepest part of that damaged score and can run out toward the corner.

Wheel diameter and included angle shape the outcome more than the printed capacity figure. Rubi supplies a 22mm wheel as standard on the TX and offers tungsten carbide options down to 18mm for harder bodies. Sigma standardises a 20mm wheel and sells a titanium-coated variant.

On a 10mm plank, the larger wheel tends to track straighter, although it asks for more downward force. That extra force bends the bar, so a cutter can feel solid at the handle while the score at the far end has already moved away from the intended line.

Feldspar Hardness Shows Up on the First Cut

Porcelain bodies vary in hardness by clay blend. A body high in microcline feldspar resists the wheel and needs a heavier, slower single pass. Cartons do not print grit hardness, so the installer discovers the body through the first trial cut. The practical check is a 30cm offcut scored at normal pressure. If the wheel chatters or the snap tears, the job needs a fresh wheel and slower travel.

The Sigma 3L Klick concentrates breaking force through a two-point foot that clicks down onto the scored line. On planks up to 100cm, this produces a reliably clean break. At 120cm, the foot geometry places pressure inside the last third, and a high-feldspar body can hinge slightly before it parts.

The Rubi TX-1250 uses a wider double-cam breaking foot spanning roughly 45mm. That wider contact spreads the snap load and often parts a long rectified plank in one decisive break.

Take a 120cm by 30cm plank at 9mm, scored once at moderate pressure. On the Sigma, a break started with the click foot travels the full length in most attempts. When it fails, the usual loss is a curved run-off near the far corner, costing about 4cm to 6cm of usable edge.

On the Rubi, the wider foot tends to fail differently. A stepped break can appear at midspan, sometimes recoverable by re-scoring. The whole plank is lost less often, although neither machine removes waste on the hardest bodies.

The 30cm offcut test is useful for wheel chatter and snap quality on that particular body. It cannot show how the same plank behaves at full 120cm length, where bar deflection and foot geometry become the main variables. A short offcut can pass cleanly and a full plank from the same batch can still run off during the snap, so the only meaningful trial for a hard body is a full-length cut from the batch being installed.

When the Rail Cutter Leaves the Job

Rectified porcelain thicker than 12mm, or any cut requiring an internal notch, moves to a wet bridge saw with a continuous rim diamond blade. A manual cutter scores and snaps a straight line. It cannot produce an L-cut for an outlet or a curved cut for a drain.

Substrate Movement Can Break a Perfect Plank

A flawless 120cm plank can fail within a heating season if the substrate moves beneath it. Large format porcelain has almost no capacity to flex, so the bed and decoupling layer carry the deflection budget.

Over anhydrite screed, the sequence is set by the chemistry of calcium sulphate. Heated calcium sulphate screed must dry to below 0.5% CM moisture, verified by carbide bomb testing. The laitance surface then needs mechanical abrasion and an anhydrite screed primer before any cementitious adhesive reaches it.

If the primer barrier is skipped, cement adhesive and calcium sulphate react at the interface. Months later, the bond can fail as a powdery layer.

The Schluter Ditra uncoupling mat handles lateral movement between screed and tile. Its 3mm polyethylene layer with cutback dovetail cavities allows limited independent movement between the substrate and the tile bed. On underfloor heating screed, where expansion and contraction repeat through each cycle, the mat absorbs shear that would otherwise crack a rigid 120cm plank or debond the corners. Movement joints still remain part of the same floor build-up.

Bonding a 120cm plank demands full coverage. A notched trowel alone leaves ridges and voids under large format tile, so the technique is to back-butter the plank, float the substrate, comb both in the same direction, and knock the ridges flat. Voids under large format porcelain concentrate point loads and create the hollow tap that comes before a cracked plank. The adhesive must be a C2 class deformable cementitious product, S1 or S2 flexible for heated floors, matched to the tile weight per unit area.

Movement Joints on a 120cm Grid

Field movement joints are required on large format porcelain over heated screed. The trade rule is a perimeter joint at every wall and column, plus intermediate joints that break the floor into bays no larger than roughly 8m by 8m for heated installations. Where glazing creates stronger solar gain and larger surface temperature swings, the bays tighten.

With 120cm planks, joint placement collides with the tile grid. A movement joint landing mid-plank cannot be formed cleanly; it has to fall on a grout line. Planning the joint layout before the first plank is set keeps joints on grout lines and away from plank centres.

The visible compromise is colour matching. The movement joint is filled with a matching flexible silicone or a proprietary joint profile, while the rest of the floor uses cementitious grout. Along a 120cm line, even a small colour mismatch shows immediately.

Doorway thresholds and substrate changes need a joint as well. A tiled floor running from a Ditra-covered heated bay onto a wet room backer board section over a different substrate has to break at that transition, because the two zones move at different rates and temperatures.

Waste, Wheel Life, and the Wet Room Edge

Budgeting for a 120cm format changes the material order. On a 20 square metre floor of 120cm by 20cm planks laid in a third-bond brick pattern, roughly 12% to 18% of planks need an end cut, and a portion of those cuts fail on hard bodies.

A carbide scoring wheel on either the Rubi TX-1250 or the Sigma 3L Klick has a finite clean-cut life. On a high-feldspar body, that working life shortens noticeably. A dull wheel is the single most common cause of a torn snap that installers blame on the machine.

The order quantity that follows is a 10% overage on plank count for cutting waste on rectified 120cm stock. That rises toward 15% where the pattern forces many end cuts or the body proves hard on the test offcut. Keeping two spare wheels on the bench lets a dulling edge come off the cutter before it ruins a full-length plank worth several times the wheel price.

Backer board joints and the tile grid rarely align at the wet room boundary. The cut planks meeting the shower area often carry the narrowest, most fracture-prone offcuts of the whole job. That is where the narrowest offcuts show the machine’s break behaviour most plainly.