LATHE OPERATIONS - OD1645 - LESSON 1/TASK 1
threads. Engine lathes are made in various sizes; the size is determined by
the manufacturer.
Generally, the size is determined by the following
measurements: either (a) the diameter of the workpiece will swing over the
bed, or (b) it will swing over the cross-slide, and (c) the length of the
bed, or (d) the maximum distance between centers. For example, using method
(a) and (c), a 14 inch x 6-foot lathe has a bed that is 6 feet long and will
swing work (over the bed) up to 14 inches in diameter. The maximum distance
between centers indicates the dimension, in inches, of the longest length of
material that can be placed in the lathe.
(2) Bench-Type Engine Lathe.
(a) The bench-type engine lathe (figure 1 on the following page), is the
most common general purpose screw cutting lathe normally found in a small
shop. It commonly has an 8 to 12 inch swing and a 3 to 5 foot bed length,
the size being limited by the practicality of bench mounting.
The bench
upon which the lathe is mounted may be a standard wood-topped shop bench or
a special metal lathe bench with drawers for storing the lathe accessories.
(b) The bench-type engine lathe is generally powered by an electric
motor, mounted to the bench behind the lathe headstock, and is driven by
means of a flat leather belt.
Some bench lathes use an underneath motor
drive where the drive belt passes through a hole in the bench.
This
arrangement is convenient where space in the shop is limited.
The bench-
type engine lathe is generally equipped with the necessary tools, chucks,
lathe dogs, and centers for normal operation. The lathe may have a quick-
installed singly or in combination to achieve the proper threading feeds.
The bench lathe may or may not have a power-operated crossfeed drive.
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