Lathe Operations: Facing

Facing Operations Facing is the process of removing metal from the end of a workpiece to produce a flat surface. Most often, the workpiece is cylindrical, but using a 4-jaw chuck you can face rectangular or odd-shaped work to form cubes and other non-cylindrical shapes.

When a lathe cutting tool removes metal it applies considerable tangential (i.e. lateral or sideways) force to the workpiece. To safely perform a facing operation the end of the workpiece must be positioned close to the jaws of the chuck. The workpiece should not extend more than 2-3 times its diameter from the chuck jaws unless a steady rest is used to support the free end. Cutting Speeds

If you read many books on machining you will find a lot of information about the correct cutting speed for the movement of the cutting tool in relation to the workpiece. You must consider the rotational speed of the workpiece and the movement of the tool relative to the workpiece. Basically, the softer the metal the faster the cutting. D…

Types of Drives in Slotting Machine

These machines utilize three types of drives. These are rack driven, screw driven, and crank driven. The crank driven being most common because of the variety of work, which they undertake, normally.

Main Parts of Slotting Machine  

The various main parts of slotting machine are as mentioned below:

  • Frame or Column. This is a massive casting of great strength designed to carry all the working part of the machine.

  • Table. Table of slotter holds the work piece and is adjustable in longitudinal and cross-wise directions. The table can be rotated about its centre. Hand wheels are provided for longitudinal, cross and rotary movements of the table.

Note: The transverse and longitudinal movements are at 90° to each other.

  • Carriage. This carries the table to which it is mounted and provides means for transverse movement of the table.

  • Saddle. This is mounted on the carriage, which carries the table and provides means for longitudinal movement of the table towards or away from the column.

  • Bed Ways.  These carry the saddle and provides guide for the longitudinal movements of the saddle.

Slotting Machine Diagram

  • Ram. This part carries the cutting tool. It is similar to the ram of shaper but more massive and moves vertically or at a right angle to the table instead of having the horizontal motion of the shaper.

  • Ram Guides. These restrict the ram to its path of motion

  • Counter Weight. The ram of the Slotting Machine is a hanging part. The counter weight acts as a balancing weight for the ram during the operation and prevents jerky action of the ram.

  • Cone Pulley. This is the driving pulley to which power is applied from an external source to drive the slotter. The steps provide a different speed of driving.

  • Drive Pinion. This is keyed to the cone pulley shaft and meshes with large bull gear.

  • Bull Gear. This gear is much larger than the drive pinion and gives the necessary relative speed reduction between the cone pulley and crank disc.

  • Crank Disc. The disc is keyed to the bull gear shaft and revolves with it.

  • Crank. The crank is movably mounted in a radial slot in the crank disc to which it can be rigidly clamped.

  • Stroke Adjustment Screw. By turning screw one way or the other, it may be moved towards or away from the crank disc, centre, thus shortening or lengthening the ram stroke.

  • Connecting Rod. This link connects the ram and crank and changes the rotary motion of the crank into the reciprocating motion.


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