TABLE OF CONTENTS Many of the countersinks are designed to use replaceable inserts or blades. Surprisingly the variety of designs is as varied as for solid cutters. Like the solid version tools, there is a scarcity of data describing tool angles.
The G-spot drill by Competitive Carbide (Fig. 3-112) uses straight flute drill inserts and a separate set of small inserts to form chamfers or spotfaces. Like other tools this allows the user to drill holes and produce the chamfer in the same operation. This tool uses two non-industry standard carbide inserts to provide up to a 0.060 in. chamfer. The tool is also used to provide complete porthole machining.
Fig. 3-113a illustrates a typical single-flute carbide insert countersink. One uses a triangular insert and the other uses a standard square insert. Fig. 3-113b shows the design of the triangular insert tool. The tool with square inserts allows inserts to be positioned up or down to provide differing diameters of countersink. Both configurations are designed to be used in rigid spindles and power feed. One manufacturer uses triangular insert number TPGH321 in C5 and C6 carbide or a TiN coated insert. The square insert used in these tools is SPGH433 in the same C5 and C6 or TiN coated configuration. These are positive rake tools and are standard in 60 , 82 and...
