Gang saw vs multi-wire cut marble slabs: what changes for the buyer

A gang saw cuts a marble block with a frame of blades moving back and forth. A multi-wire saw uses diamond wires running continuously around pulleys. Both cut many slabs at once. The width of those cuts and the surface they leave affect how much marble is recovered and how much finishing work follows.

Multi-wire cutting can give a smoother sawn surface, and dedicated machines can produce thin slabs. Whether it also gives more marble from the same block depends on the slab thickness and how much stone each cut removes. For a finished slab, the work after sawing matters too: a rough surface straight off the saw is not the surface delivered to the customer.

How the two cutting methods work

In a marble gang saw, parallel blades fitted with diamond segments are tensioned inside a frame. The frame moves back and forth while the blades advance through the block, or the block rises into them. The spacing between the blades sets the slab thickness. Pedrini's GS131 marble gang saw, for example, uses this reciprocating frame arrangement.

A multi-wire saw makes the parallel cuts with loops of diamond wire. Pulleys drive the wires continuously, and guides hold them at the required spacing. Wire tension keeps the cutting path controlled as the machine works through the block. Breton's Paragon is one example, offered for marble slabs of 20 mm, 30 mm and greater thicknesses.

Both methods remove stone along every cut. That gap is the kerf. A thinner gap leaves more of the block available for slabs; a wider one turns more of it into cutting waste. This is where the yield comparison starts.

Which method gives more slabs from a block?

At the same sawn thickness, the method with the narrower actual cut leaves more stone for slabs, provided breakage and other losses are equal. The name of the saw doesn't tell you how wide that cut is.

Take two illustrative cut widths, 4 mm and 6 mm. These are assumptions for the calculation, not measured figures for a gang saw or a multi-wire machine. With a 20 mm slab, each repeating slab-and-cut section occupies either 24 mm or 26 mm of the block.

For a regular block, a simple estimate is:

The two examples give about 41.7 m² and 38.5 m² per cubic metre. That is before edge and end losses, trimming, breakage or rejection. It also uses the thickness at sawing; any allowance needed for later grinding has to be included in that thickness.

The difference matters because the block has already been paid for. Recover more usable area from it, and the block cost is spread across more square metres. For the same percentage improvement, the saving is larger on an expensive block than on a cheaper one. Cutting, treatment, finishing and packing still have their own costs, so the reduction in block cost is only part of the finished price.

Multi-wire is not a single cutting width

Pedrini lists 4.3, 5.3 and 6.3 mm diamond bead diameters for its Jupiter GS230 marble multi-wire machine. Those are different cutting configurations within one machine family. A published bead diameter is useful technical information, but it should not simply be substituted for a measured cutting gap. On a gang saw, the steel blade body and its cutting segments are different dimensions too.

Slab thickness can make an even larger difference to a quoted yield. In its published marble cutting overview, Pedrini gives up to 39.2 m²/m³ for a GS240 using 4.3 mm wire on 20 mm slabs, and up to 55.5 m²/m³ for its TECH12 using 5.3 mm wire on 12 mm slabs. These are the manufacturer's figures for two different products, not a like-for-like comparison of saw efficiency.

The higher area figure includes a much thinner slab. You cannot use it to predict how much 20 mm marble a machine will produce.

So multi-wire can improve material recovery where its actual cut is narrower. Establishing how much it improves recovery over a particular gang saw requires comparable production figures at the same slab thickness. Neither a headline yield nor the word "multi-wire" supplies that comparison on its own.

Does multi-wire cutting make a better marble slab?

It can give the finishing line a better starting surface. A 2026 study at a natural stone plant in Türkiye, comparing blade and wire systems across five stone types, reported smoother sawn surfaces with the wire system and less subsequent polishing effort.

Keeping the wire in position is part of achieving it. Breton describes vibration control and precise wire positioning as central features of its Paragon design. A wire running continuously still needs to be guided and tensioned correctly.

After sawing, slabs go through further processing. Where thickness correction is needed, calibration removes material to bring the slab to the required thickness. Grinding and polishing then develop the finished face. A cleaner initial cut can reduce the work needed, but it doesn't eliminate the need to check the finished slab.

In our own production, a separate thickness-calibration step is available, but our gang-sawn slabs generally come off the machine in good enough condition that it does not need to be used.

For the customer, thickness and flatness describe different things. A slab may be the right average thickness but vary from one part of the face to another. Flatness concerns the shape of the face itself. These affect how the material can be fabricated and installed, so the finished measurements need to meet the agreed specification whichever saw was used. Our marble pre-shipment inspection guide covers checking the material before it leaves.

Cracks also need to be considered separately from the surface finish. In the same factory study, pre-existing cracks in the blocks were a major cause of poor slab quality with both systems. In our own work, sawing can open an existing fissure further. A smooth cut does not remove that weakness from the stone.

This is why repair and reinforcement remain part of marble processing. We carry out whole-slab resin treatment and mesh backing in-house, as well as repair after cutting. The condition of the stone and the quality of that work deserve attention alongside the cutting method; resin-filled marble slab quality is a separate part of assessing the finished material.

Where block cutting fits in our production

At Excellent Stone, we use gang saws for our own block cutting. On orders that start this way, we plan block use together with the fabrication that follows. The yield goes into our own material cost, and we carry the stone through treatment, fabrication, inspection and packing.

For a project buying finished pieces, this means block cutting and fabrication to the project drawings can be organised within the same production operation. Our role starts before there is a finished slab to buy.

Some orders start with finished slabs sourced from the Shuitou market, where a particular variety or selection suits the project. Those slabs also go through our production and inspection, but their block cutting has already happened. We use both supply routes.

For either route, we measure every slab for size and thickness and retain photographs of the measurements.