INTRODUCTION TO METAL CUTTING:
Metal cutting is the process of producing a job by removing a layer of unwanted material from a given workpiece. Fig. shows the schematics of a typical metal cutting process in which a wedge shaped, sharp edged tool is set to a certain depth of cut and moves relative to the workpiece.
SLOTTING MACHINE
Introduction: The slotting machine is a reciprocating machine tool in which, the ram holding the tool reciprocates in a vertical axis and the cutting action of the tool is only during the downward stroke.
Counter sinking: Counter sinking is the operation of making a cone shaped enlargement at the end of a hole to provide recess for a flat head screw or a countersunk rivet. The counter-sunks (tools used for counter sinking) carry included angles of 60°, 82° or 90° and the cutting edges of the tool are formed at the conical surface.
Counter boring: Counter boring is the operation of enlarging one end of an existing hole concentric with the original hole with square bottom. It is done to accommodate the heads of bolts, studs and pins. The cutting edges of the counter-bore (tool used for counter boring) may have straight or spiral teeth.
Reaming: The holes that are produced by drilling are rarely straight and cylindrical in form. To produce accurate and smooth holes, the drilled holes are reamed by a tool called reamer. The reamer is a cutting tool having several cutting edges in straight or helix shape.
Boring: Boring is the operation of truing and enlarging a previously drilled hole by means of a single point cutting tool. Boring is done on drilling machine to perform the following tasks on a hole already drilled:
Tapping: Tapping is the operation for making internal threads in a hole by means of a tool called tap. The tap is essentially a bolt with threads cut on it.
Spot facing: Spot facing is the operation of smoothing and squaring the surface around and at the end of a hole so as to provide a smooth seat for a nut or for the head of a cap screw. Spot facing is generally done on castings and forgings.
Drilling: Drilling is the operation of producing a hole by removing metal from a solid mass by the rotating edge of a cutting tool known as drill.
DRILLING MACHINE
Introduction: The drilling machine or drill press is one of the most common and useful machine employed in industry for producing forming and finishing holes in a workpiece. The unit essentially consists of: