Widia’s Top Ream range of reamers has been added to the hole-making portfolio available from Tamworth-based Industrial Tooling Corporation Ltd (www.itc-ltd.co.uk).

Conventional carbide-tipped reamers produce good hole quality and are considerably faster than boring tools — plus they can reach much deeper, but there is a drawback: the steel shank that is brazed with the carbide flutes has a thermal co-efficient three-times that of carbide, making it subject to growth during machining operations.

Furthermore, sharpening tools such as these leads to less than desirable results, as the mixture of carbide and steel can ‘wreak havoc’ with grinding wheels.

Indeed, Widia says that achieving a re-ground edge as good as the original tool is almost impossible.

Instead of four to eight individually brazed carbide tips, Widia’s Top Ream uses a single carbide disc and brazed joint. According to the company, this provides a strong connection that is virtually immune to thermal effects during machining operations.

Widia manufacturing engineer Tom Bobos highlights another advantage of Top Ream’s all-carbide tip: “Steel-bodied reamers tend to get knocked on the end, distorting the centre and preventing an accurate regrind. With carbide, you always have a good centre on which to locate.

The result is a minimum of four ‘like new’ regrinds versus an average of three questionable ones. What’s more, a single piece of carbide is inherently more stable and resistant to vibration, while an 18deg left-hand spiral does a great job of pushing the chip forward.”

Top Ream features Widia’s WU05PR carbide grade, which was developed specifically to achieve the tool-wear and surface-finish requirements of most reaming operations.

For example, tests performed over a total cut depth of 30m showed an ability to consistently maintain surface finishes of 0.8Ra in the steel alloy 4140 and 1.6Ra in grey cast iron. Widia says this is three-times that of TiAlN-coated tools.

Top Ream covers diameters up to 42mm, while the TRF shanks start at 14mm and the TRM modular tools at 20mm.

One of the best features of the Top Ream line is the TRM series’ mounting mechanism, which makes simultaneous contact on the face and taperof the cutting head, to ensure a strong, vibration-free and precise reamer interface.