CNC Lathe Tools you Need for Turning: Guide

Lathe machines use various tools. You can use most of them interchangeably on manual and CNC lathes, but some are reserved for CNC lathes.

CNC lathes offer a greater advantage over manual lathes, allowing for the automated production of accurate and repeatable parts while reducing the work cycle.

These machines and the tools used on them have a high initial cost, but their ability for large production volumes and complex geometries easily compensates for the high cost.

CNC lathe tools are cutting tools used on a CNC lathe machine to perform machining operations like turning, facing, boring, knurling, threading, etc. These cutting tools are available in multiple shapes and forms. They are selected based on the planned part geometry, workpiece material, surface finish, machining conditions, etc.

This article discusses the various tools used to machine different parts on a CNC lathe and clarifies how to select the right tool for your job.

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6 CNC Lathe Tools That are Essential

There are a variety of lathe tools, each used for various jobs. They can be classified based on the tool material, structure, feed mode, and type of operation they're employed.

Lathe-cutting tools can be entirely made from High-speed tool steel or have carbide and diamond inserts for cutting hard materials.

Inserts can also be made with cubic boron nitride and ceramics for machining hard alloys.

Tool structure refers to the connection between the cutter head and the rod.

Integral lathe tools are made from solid HSS. Other tools have a welded or clamp-on connection between the cutter head and the shank.

Mechanical clamping allows easy blade replacement and is very common among CNC lathe tools.

Based on the feed, the tool can be either a left-hand or right-hand tool.

Left-hand tools have a cutting edge on the right side and are fed in the left-to-right direction. It is exactly the opposite for right-hand tools.

The lathe tools are also classified based on the operations performed. They are the following.

CNC Lathe Tools	Function
Turning Tool	Used to produce symmetrical parts
Boring Tool	Used to shape and enlarge machined holes
Facing Tool	Used to machine a flat face
Chamfering Tool	Used to create a beveled transition between two faces on a stock
Knurling Tool	Used to produce straight or diagonal patterns
Parting Tool	Used to completely cut out a part from the stock

Turning Tool

The turning tool is a single-point cutting tool used on a CNC lathe. It is laid on a rotating workpiece to produce precise symmetrical parts.

Rough turning tools remove large amounts of material as they have a small clearance angle. These tools are strong and can handle considerable cutting pressure.

Fine-turning tools are used for finishing operations. They have a large clearance angle and remove small amounts of surface material resulting in a smooth surface finish.

Boring Tool

Boring tools are internal diameter (ID) cutting tools used to enlarge existing holes.

They have a single cutting point, allowing you to remove material quickly and accurately.

The tool consists of a cylindrical bar and one insert that reaches inside the cavity to remove material.

They produce holes larger than standard drills, resulting in a precise and straight hole. It can also be used for non-standard sizes and create holes with a good surface finish.

Facing Tool

A facing tool has cutting edges at the sides and is used to machine a flat surface perpendicular to the axis of rotation of the workpiece.

It is fed axially across the axis workpiece to remove material from the workpiece's end or face, resulting in a flat surface.

Chamfering Tool

Chamfering tools have an angled cutting edge used to create a beveled transition edge between the two faces of the workpiece.

The chamfering process removes shard edges on a workpiece, thereby eliminating stress concentration points resulting in a stronger part, making it safe to handle.

Knurling Tool

Knurling tools produce straight or diagonal patterns on the workpiece surface.

The tool consists of a holder and steel wheels having a specific pattern. The wheels are pressed into the rotating workpiece surface to create knurled parts.

It improves the part's grip and makes it easy to handle. These designs are also used to give an aesthetic appeal to cylindrical parts.

Parting Tool

Parting tools have a narrow cutting edge that works its way into the workpiece to cut it at the desired length. You can also use it for turning and facing operations.

They are one of the most used CNC lathe tools. Once a part is machined, a parting tool separates the finished part from the main body clamped in the chuck.

CNC Lathe-specific Tools

You can perform certain operations only on a CNC lathe machine as it involves synchronizing the cutting tool's movement and the workpiece's rotation.

Such a level of synchronization cannot be achieved using manual machines.

Because of their high material removal rate, these CNC lathe-specific tools can machine complex geometries faster than most milling machines.

CNC lathes can also be used for rotary broaching operations to produce cavities of desired shapes.

In addition, CNC lathes use live tooling to perform various complex jobs, which otherwise require the part to be moved from a lathe to a mill. This results in a reduced work cycle.

CNC Lathe-specific Tools	Function
Polygon Turning Tool	Used to machine polygonal shapes at the end face or the circumference of the workpiece
Threading Tool	Used to make uniform helical ridges on the workpiece
Face Drill Tools	Radially driven live tools used for drilling, tapping, and reaming jobs
Cross Drill Tools	Axially driven live tools
Adjustable Angle Tools	The tool angle can be adjusted

Polygon Turning Tool

The polygon turning tool is used on a CNC lathe machine to cut complex polygonal shapes at the end face or the circumference of the workpiece.

These tools have multiple cutting inserts equally placed at their ends or along the circumference.

Here the tool and workpiece rotation is synchronized so that the cutting inserts cut the workpiece at the same position in each rotation.

Using a polygonal tool, you can machine hexagonal or square ends for parts like nuts on a CNC lathe faster than any other machine.

Threading Tool

Thread cutting makes uniform spiral ridges on the workpiece surface. Threading is done on a CNC lathe using an indexable threading insert.

For a threading operation, you must choose an insert with the same size and shape as the required thread.

The cutting tool advances the stock uniformly per spindle revolution, resulting in consistent thread pitch. This is achieved by programming a constant feed and RPM rate.

Threading is a multipass operation and requires a CNC system to provide synchronized motion for each threading pass.

Face Drill Tools

Face drill tools are radially driven live tools. You can use them to perform various operations such as drilling, rigid tapping, reaming, etc.

They come in various forms having offset centers, multiple output shafts, and extended handles for reaching large parts. Expensive ones can also have a provision for coolant.

You can mount them in different configurations for radial and axial machining.

Cross Drill Tools

Cross-drill tools are similar to face drill tools, but they are axially driven. They can also perform all operations as a face drill.

You can even mount them on the face of the tool plate for axial machining.

Adjustable Angle Tools

Adjustable angle tools are a great alternative to face and cross drills. They sit on a unique holder that can be adjusted axially, radially, or at any other angle in between.

Selecting a CNC Lathe Tool - Things to Consider

The tools used on a CNC lathe greatly influence the machining process. Understanding the machine and tools can help you make the right choice.

A lot depends on the type of material to be machined. Material hardness plays a significant role in selecting the right cutting tool.

Harder metals, like tungsten, steel, etc., require tools with carbide or diamond cutting inserts, while softer metals can be turned using high-speed steel (HSS) cutters.

The location of the cutting edge determines the cutting direction.

Left-hand tools are better suited for turning rigid materials at close tolerance as the cutting forces are directed into the machine, providing stable machining operation.

Right-hand tools are the most used and readily available. They direct the cutting forces outward from the turret and are less stable in comparison.

You can use right-hand tools for most turning jobs unless enormous cutting forces are involved.

Finally, you also must consider the cutter shape as it greatly influences the turned part. Some part designs need to be worked with multiple tools to achieve the desired shape.

Live tools offer a great degree of flexibility and can perform various operations apart from standard turning. They can also save a lot of time when machining complex parts.

Final Thoughts

You can perform turning operations on a manual or a CNC lathe machine.

CNC lathes have a higher upfront cost and require skilled labor, but they can make repeatable parts in less time.

With a live tool, you can further boost production by making tricky parts that need to be worked with a different machine, like a CNC mill or router.

Selecting the right tool can significantly improve productivity, the machining process, and the quality of the finished product.

Frequently Asked Questions

What is the difference between a lathe and a milling machine?

The main difference between a lathe and a milling machine is the tool's and the workpiece's rotation. In a lathe machine, the workpiece rotates while the tool is static in most operations, while the milling machine uses a rotating tool to remove material.

What are the types of turning?

There are mainly three types of turning operations: straight turning, taper turning, and profiling. You can perform these operations on a manual or a CNC lathe.

What is an automatic tool changer?

An automatic tool changer is a robotic tool bank used in CNC machining centers enabling it to rapidly change tools without requiring manual assistance from a CNC operator. It allows the machine to handle many tools while improving productivity by reducing downtime.