ATA International Product Catalogue

201500 1579 606- 609 BI-METALL COBALT 8% NOTES ON USE FOR BI-METAL HOLE SAWS HSS-E COBALT 8% 1  Use a good cutting oil when drilling metal. (see from page 1363) . If the tooth tips are blue, the saw has been used without cutting oil or at too high cutting speed. Calculation of the cutting speed (Vc) n = Speed (rev./min.) (see page 1578) d = Hole saw diameter in mm Vc = Cutting speed (m/min.) 2  Do not tilt the hole saw in the hole 3  If large hole diameters are used in hand-held drills, the hand-held drill must be held particularly firmly. A drill stand should be used where possible. We recommend for hole saw diameter 100 mm and more our heavy duty arbour 20 1528 (page 607) . 4  Lift the saw clear frequently when cutting timber, chipboard, and wood substitutes and remove the sawdust and chips. If this is not done, the tooth tips can burn and the hole saw will jam in the cut. 5  If cutting especially thick timber, chipboard and wooden substitutes we recommend our hole saws article 20 1121 pages 596- 599. 6  Enlarging existing holes Existing holes (starting with diameter 32 mm) or more in diameter may be enlarged with a simply trick. Take a small hole saw (smallest 32 mm) and screw this inside the hole saw on the projecting thread (see picture). Suitable holder are article 20 1528 and 20 1511. The inner hole saw then acts as a kind of guiding hole saw for extending existing holes. If necessary, remove the center drill. π × d × n Vc = 1000 11 Index 10 9 OIL 8 7 6 5 4 3 2 1