High precision chamfering of small bores

For rapid, , a new range of purpose-designed cutters has been introduced by BIG Daishowa, Japan. Called C-Cutter Mini, the tools have square, indexable, carbide inserts secured firmly by a screw. The bespoke design ensures good surface finish and long insert life, despite high feed rates up to 0.4 mm/rev. This is in contrast to some tools on the market that use standard inserts, which tend to chatter when chamfering due to compromised rake and clearance angles. Overlapping chamfering ranges allow seven variations of cutter to machine bores from 2 to 42 mm diameter, with back chamfering also available in some styles. The number of tool changes is consequently reduced, thereby increasing productivity. Standard chamfer angle is 45° although BIG Daishowa also offers a 30° and a 60° cutter in the Mini programme. Cylindrical shank diameters are from 10 to 32 mm and there are various insert styles and sizes to suit. Machining is achieved by interpolating the Mini cutters, whereas with larger BIG C-Cutters for bores up to 100 mm diameter, contouring can be replaced by very accurate plunge-chamfering.