What is a Turret Lathe & How It Works - Turret Lathe vs Engine Lathe & Turret Lathe vs Capstan Lathe

What is a Turret Lathe & How It Works – Turret Lathe vs Engine Lathe & Turret Lathe vs Capstan Lathe

2021.5.15

A lathe machine can be used for CNC turning, drilling, reaming and more operations. The development of lathe design minimizes human labor and improves working efficiency. To fit various needs and simplify the procedure, such a metalworking lathe – turret lathe is created. In this article, we’ll learn about what is a turret lathe and its working principle, as well as the comparison between turret lathe and engine lathe, turret lathe and capstan lathe.

What is a Turret Lathe?

The turret lathe is a type of metalworking lathe machine that developed from earlier lathes, adding a turret, which is a kind of indexable tool holder, allowing to perform multiple cutting operations on one machine with different tools, without the need for the operator to do set-up works or control the toolpath. The general form of the early turret is a flattened cylindrical block mounted to the cross slide of the lathe, it can rotate around the vertical axis and with tool holders projecting out to all sides, resembled a swiveling gun turret, that’s how turret lathe gets its name. On traditional lathes, it may take several minutes to replace the cutting tool manually, but the turret lathe can switch to the proper cutter automatically, which brings faster and more efficient production.

How Does a Turret Lathe Work?

Before the cutting is performed, the workpiece to be machined is fixed in the chuck of the lathe, then all the cutting tools are placed in the corresponding holes of the hexagonal turret. The chucks are rotated by rotating the spindle. When the chuck rotates, the workpiece attached to the chuck will also rotate. By moving the saddle, the hexagonal turret head will move towards the rotating workpiece. The hexagonal head can be rotated, by which the required tool is oriented towards the workpiece. When the required tool faces the workpiece, the tool contacts the workpiece and performs the required operation. When one tool is used to complete an operation, the other tool moves forward and performs different operations by rotating the hexagonal turret head. In the manual turret lathe, the required tools are directly used by the operator through the turret, but in the automatic turret lathe, the required tools are not directly used by the operator, after each operation, the head of the turret will return to the initial position, and the tool will automatically index.

Types of Turret Lathe

Turret lathe can be divided into lots of different types based on their constructions, uses and other characteristics.

1. Ram-type Turret Lathe: the most common type of turret lathe, where the turret is mounted on a ram that moves back and forth along the bed of the lathe.

2. Saddle-type Turret Lathe: the turret is mounted on a saddle that moves along the bed of the lathe, allowing for more precise control and heavier cutting.

3. Vertical Turret Lathe: this type has a vertical spindle and is used for turning large, heavy parts, such as engine blocks and cylinder heads.

4. Horizontal Turret Lathe: this one is characterized by a horizontal spindle and is used for turning smaller parts, such as axles and shafts.

5. CNC Turret Lathe: equipped with computer numerical control (CNC) and is used for high-precision, high-volume production of complex parts.

6. Swiss-type Turret Lathe: designed for the precision turning of small, intricate parts, such as watch components and medical devices.

7. Multispindle Turret Lathe: multiple spindles allow for simultaneous turning of multiple parts, increasing productivity and efficiency.

8. Opposed Turret Lathe: there are two turrets, one on either side of the lathe, capable of simultaneous turning of two parts, increasing productivity and efficiency.

9. Twin-spindle Turret Lathe: two spindles are used to turn two parts at the same time, increasing productivity and efficiency.

10. Flat-bed Turret Lathe: a flat bed used for turning large, flat parts, such as engine blocks and cylinder heads.

Turret Lathe vs Engine Lathe - Difference Between Turret Lathe and Engine Lathe

1. Turret lathe is faster than engine lathe.

2. Turret lathes require more time for setting, engine lathes need less time for setting.

3. In the turret lathe, if a one-time tool set, no tool changing is required, in the engine lathe, you can change the tool if needed.

4. The turret lathe is semi-automatic and the engine lathe is manually operated.

5. The price of turret lathe is generally higher.

6. Tool wear problems are more common in engine lathes.

7. Tailstock of a turret lathe has a turret that can carry multiple tools, the tailstock of an engine lathe can hold only one tool of limited size.

8. Turret lathes need fewer skilled operators, and engine lathes need skilled workers to control.

Turret lathe and engine lathe, which one should you choose?

The engine lathe is more suitable for low-volume job shops, tool rooms, project work, and prototyping, use it if you want to complete smaller batch production and one-off custom parts. It is also used for general turning, grooving, threading, and other basic operations.

Turret Lathe vs Capstan Lathe - Difference Between Turret Lathe and Capstan Lathe

1. The turret lathe is a heavyweight machine and the capstan lathe is a lightweight machine.

2. In the turret lathe, the turret tool head is mounted over the saddle like a single unit, in the capstan lathe, the turret tool head is mounted over the ram and that is mounted over the saddle.

3. In turret lathe, the saddle is moved for providing feed to the tool, while in capstan lathe, the ram is moved for the same purpose.

4. In turret lathe, turret tool head moves along with the saddle over the entire bed in the longitudinal direction. In capstan lathe, there is no saddle displacement, the movement of the turret tool head over the longitudinal direction of the bed is small along with the ram.

5. The turret lathes mainly used for longer workpieces, which with up to 120 mm diameter and capstan lathes are suitable for shorter parts, which with up to 60mm diameter.

6. The operations of turret lathes are slower due to the heavier construction and the working of capstan lathes are fast as the lighter construction.

7. Heavy cuts on the stock can be performed on turret lathes, and that can’t be given on the capstan lathe.

8. In turret lathe, a power jaw chuck is used to grip the piece and in capstan lathe, the collet plays the same sole.

9. Turret lathes are available in horizontal and vertical types, capstan lathes are usually horizontal lathes.

10. In turret lathe, the turret head can be moved crosswise such as in the lateral direction of the bed, but the capstan lathe can’t do that.

11. In turret lathe, the turret is rotated manually after releasing the clamping lever, for indexing the tool head, in capstan lathe, the handwheel of the ram is reversed and the turret tool index automatically.

How to distinguish between a turret lathe and a capstone lathe?

Visually, a turret lathe has a rotating turret or hexagonal tool post that can be indexed to different positions. This turret is typically mounted on a slide or carriage that can move along the lathe bed, there are multiple tool stations or holes on the turret. A capstan lathe has a fixed tool post or capstan with only one single tool station or hole. This tool post does not rotate or index to different positions. It also has a ram or piston that moves back and forth along the lathe bed.

When it comes to operations, if we need to turn a shaft with a shoulder, groove, and threads, on a turret lathe, you need to load multiple tools – a turning tool, a grooving tool, and a threading tool. The program would turn the shoulder, index to the grooving tool, and cut the groove, then index to the threading tool and cut the threads, all automatically. While on a capstan lathe, you need to do each step manually, first turning the shoulder, then stopping the machine, changing to the grooving tool, and cutting the groove. Then again changing to the threading tool to cut the threads.

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