Understanding Capstan Lathe Turret Mounting

The question asks about the specific component on which the turret of a Capstan lathe is mounted. To answer this, we need to understand the construction and key features of a Capstan lathe.

What is a Capstan Lathe?

A Capstan lathe is a type of turret lathe designed for producing multiple identical parts efficiently. It differs from an engine lathe primarily in how the cutting tools are held and presented to the workpiece. Instead of a compound slide holding a single tool, a Capstan lathe uses a turret that can hold several tools, allowing for rapid sequencing of operations.

Components of a Capstan Lathe

Key components of a Capstan lathe include:

• Headstock: Holds the spindle, chuck, and gearing for different speeds.
• Bed: Provides the guide ways for the saddle and cross slide.
• Saddle: Moves along the bed and supports the turret assembly.
• Turret: A rotatable indexing head that holds multiple tools (usually hexagonal).
• Ram: A short slide on which the turret is mounted, allowing the turret to move back and forth for feeding tools.
• Cross Slide: Located between the headstock and the turret assembly, it holds tools for operations like facing, parting, or form turning.

Analyzing the Turret Mounting in a Capstan Lathe

In a Capstan lathe, the turret is mounted on a distinct component called the 'ram'. This ram is a short slide that itself moves longitudinally on the saddle. The saddle provides the main movement along the bed, while the ram allows for a shorter, quicker feeding movement of the turret tools towards the workpiece. This design facilitates rapid tool changes and feeding, which is crucial for high-volume production.

Let's look at the given options:

• Headstock: The headstock holds the spindle and drives the workpiece. The turret is not mounted on the headstock.
• Copy turning attachment: This is an optional accessory for duplicating profiles, not the standard mounting point for the main production turret.
• Compound slide: A compound slide is typically found on engine lathes to hold a single tool and allow angular feeding. Capstan lathes use a turret for multiple tools and have a different feeding mechanism for the turret assembly.
• A short slide of ram sliding on the saddle: This accurately describes the arrangement in a Capstan lathe. The turret is fixed to the ram, which slides for feeding, and the ram unit moves on the saddle for positioning along the bed.

Therefore, the turret in a Capstan lathe is mounted on a short slide, known as the ram, which moves relative to the saddle.

This specific mounting structure of the Capstan lathe's turret on the ram allows for quick, precise indexing and feeding of multiple tools without requiring the entire heavy saddle to move for every feed stroke, enhancing production speed.

Revision Table: Capstan Lathe Components

Additional Information: Capstan vs. Turret Lathes

While often grouped, Capstan lathes and Turret lathes (sometimes called Ram Type and Saddle Type respectively) have a key difference in turret mounting:

• Capstan Lathe: Turret mounted on a short ram sliding on the saddle. Offers fast, limited stroke movement from the turret face. Best for smaller work where the full saddle travel isn't needed for every tool.
• Turret Lathe (Saddle Type): Turret mounted directly on the saddle. The entire saddle and turret assembly moves along the bed for tool feeding. Offers a longer stroke suitable for larger or longer workpieces.

This distinction in turret mounting on either a ram or directly on the saddle is a defining characteristic between these two types of production lathes.