Vincent A40 R20 Half Bullnose CNC Profile Wheel – Position 0 Segmented, 120 mm

The Vincent A40 R20 Half Bullnose CNC Profile Wheel is a 4.72 in. (120 mm) position 0 segmented roughing wheel that takes the sawn edge down to the profile line on granite, engineered stone and natural quartzite before the shaping wheels run.

A-profile construction. The A-profile is non-encapsulated — it profiles the top corner only. A T-profile of the same radius profiles both the top and the bottom corner. That construction difference, not the radius, is what separates the two: an A30 r3 and a T30 r3 cut the same radius on the top edge, but only the T also finishes the underside.

Spindle speed: 4,800–5,500 RPM
Feed rate: up to 157 in./min (4,000 mm/min)
Stock removal: up to 0.020 in. (0.5 mm)

Diameter: 4.72 in. (120 mm) · Height: 2.03 in. (51.5 mm) · Bore: 1.38 in. (35 mm)

Key Features

• Segmented rim for bulk removal — this is the first wheel in the set and the one that does the heavy cutting, not the one that sets the finish.
• Vincent publishes up to 157 in./min (4,000 mm/min) at 4,800–5,500 RPM for this position, with stock removal up to 0.020 in. (0.5 mm).
• The softer bond releases spent diamond as it wears instead of polishing over, so the wheel keeps cutting without glazing on dense material such as quartzite and porcelain.
• Fitment: 4.72 in. (120 mm) diameter, 2.03 in. (51.5 mm) working height, 1.38 in. (35 mm) bore. Vincent sizes its resin polishers to match the metals in the same set, so positions swap without re-setting the tool length.

Who Is This For

A high-production shop programming A40 R20 edges on a CNC and running them in volume. At up to 157 in./min (4,000 mm/min) this is a wheel built for unattended cycles and production throughput rather than one-off work.

It is not a polisher. Position 0 leaves a ground surface by design; the gloss comes from the position 4–6 resin polishers in the same A40 R20 set. Do not try to close the surface by slowing this wheel down — that glazes the bond and shortens its life.

Vincent lists this wheel for granite, engineered stone and natural quartzite. For technical ceramics and Dekton it publishes a separate CERAM range; running a granite bond on ceramic slab is the usual cause of chipping at entry and exit.

Frequently Asked Questions

What feed rate and spindle speed should I run at position 0?
Vincent publishes up to 157 in./min (4,000 mm/min) at 4,800–5,500 RPM for a position 0 profiling wheel of this type, with stock removal up to 0.020 in. (0.5 mm). Those are the manufacturer's figures for the position, not a shop rule of thumb.

Will it polish the edge?
No — positions 0–3 are metal bond. They cut the profile; the resin positions 4–6 polish it. Expect a ground surface off this wheel.

Will it hold up on quartzite and porcelain?
That is what the softer bond is for: it releases spent diamond rather than glazing, so the wheel keeps cutting on hard material. Vincent lists the range for granite, engineered stone and natural quartzite.

What bore does it need?
1.38 in. (35 mm). That is the standard Vincent profile-wheel spindle fitting for this range.

Is "engineered stone" the same as quartz?
Yes — engineered stone is Vincent's catalogue wording for quartz surfaces such as Caesarstone, Silestone and Cambria. The wheel is listed for them.