Jusheng

One engineer faces a hard Inconel blank, and he must shape it in the least time at the highest rate of metal removal. Another has a medical precision titanium component in mind that needs a mirror-finish surface and micron-sized tolerance.

They work on the same lathe, but victory lies with the tooling of the lathe.

Choosing the right tool can make a world of difference in efficiency, accuracy, and cost. This guide will take you to the depths of the turning tool universe, enabling you to pick the right lathe tooling easily for improved machining efficiency and quality of CNC machining parts.

Core Answer Summary

Tool Type	Application	Recommended Materials/Coatings	Key Parameters/Notes
External Turning Tool	External cylindrical surfaces, external conical surfaces, and workpiece end faces.	Carbide + TiAlN Coating	Can have right/left offsets, complex curved surfaces require more than one pass.
Internal Turning Tool	Internal hole structures such as circular and stepped holes.	Carbide / Ceramic + TiAlN Coating	Internal holes less than 10mm require a thickened/hollow shank, 30% less heat dissipation and 20%-30% less tool life.
Cut-off Tool (Cutter)	Parting tool, external/internal grooves.	Carbide + TiN Coating	Width ranges typically from 2-5mm, aspect ratio > 4:1, the parameters must be controlled to prevent breakage of the tool.
Thread Turning Tool	Internal/external triangular, trapezoidal, and rectangular threads.	Carbide + TiAlN Coating	The cutting edge is equivalent to the thread profile (variable), multiple passes need to be taken.
Forming Turning Tool	Complex rotary surfaces such as spherical and arc surfaces.	Carbide / PCD (High-Precision Scenario)	The cutting edge matches with the workpiece, re-customization is required for a switch of product types.

Why Refer To This Guide? JS's CNC Expertise

JS has been serving custom CNC machining manufacturing needs for decades to demanding markets such as aerospace, automotive, and medical and has delivered over 100,000 precision CNC machining parts projects.

JS also possesses a comprehensive tool test system. Each recommended lathe tool is tested under live machining to ensure consistent performance.

This manual is based on JS's rich practical experience. From material compatibility to cost control, all recommendations are made for actual machining conditions, so you don't make selection errors and can make more accurate decisions.

JS utilizes its extensive CNC experience and rigorous tool testing to provide a reliable tool selection guide. We will quote and proceed with production straight away once you give us your requirements. Choose JS for smooth machining!

Beyond a Piece of Iron: Familiarity with Pieces of Lathe Tools

Having understood this guide to be reliable, we can now start by disassembling a lathe tool—it consists of three primary components that collectively define the upper limit of lathe tooling performance.

Tool Holder: The 'Arm' Of The Machine Tool

The tool holder mounts the machine tool to the insert and sustains cutting force. Common materials include high-strength steel and carbide. Inexpensive ($50-150 USD) high-strength steel tool holders suit low-to-medium cutting loads.

Carbide tool holders are rigid and strong, can withstand high cutting forces, and suitable for hard-to-machine material (such as Inconel 718), but more expensive ($200-500 USD).

Accuracy of the tool holder is also critical. Taper tolerances must be closely held during machining of precision parts. If not, the insert would be in a misaligned position, affecting the precision of CNC machining parts.

Insert: The 'Teeth' of the Tool

The insert is the cutting edge that directly cuts the workpiece. Its shape and material parameters will determine the machining result. Common materials include high-speed steel,arbide,ceramic,and PCD/CBN.

Coating: The Blade's 'Coating'

Coatings add blade wear and heat resistance. Common types and characteristics are listed in the following table:

Coating Type	Applicable Materials	Wear Resistance	Heat Resistance	Applications
TiN	Mild Steel, Aluminum Alloys.	Medium	≤500°C	General Cutting, Low-Speed ​​Machining.
TiAlN	Stainless Steel, High-Strength Steel.	Higher	≤800°C	Medium-High-Speed ​​Cutting, Dry Machining.
AlCrN	High-Temperature Alloys, Titanium Alloys.	High	≤1100°C	High-Speed ​​Cutting, Difficult-to-Machining Materials.

JS can provide compatible toolholder, insert, and coating combinations. We are engaged in customized CNC machining manufacturing actively, which allows precise control of lathe tooling performance and smooth CNC machining of parts. We're eager to cooperate with you!

Detailed Explanation Of Mainstream Lathe Tool Types

After clarifying the composition of the tools, let's first sort out the core features of mainstream lathe tooling.

External Turning Tools

These are the most general basic tools, divided into right-handed tools (right to left cutting) and left-handed tools (left to right cutting). Their inserts are typically carbide.

Notice that machining complex curved surfaces (such as spheres) requires several tool passes and reorientations.

Internal Turning Tools

These are used for turning internal workpiece holes. Because the tool shank is thin and prone to vibration, a hollow or thicknessed shank is recommended for internal holes <10mm. Heat dissipation is also poor, and insert life is 20%-30% shorter than that of turning tools for external use.

Parting Tools

The cutting edge is narrow, and cutting forces are concentrated, where tool stiffness is required. Turning slender workpieces with aspect ratios greater than 4:1 has a probability greater than 30% to shatter the tool, requiring controlled cutting parameters.

Thread Turning Tools

The cutting edge must ideally be a replica of the thread profile. The tools are often special orders (considered custom CNC machining manufacturing). Multiple passes of the tool are required, resulting in comparitively low efficiency.

Forming Turning Tools

The cutting edge is the final shape of the workpiece, and therefore they can be utilized for mass production to ensure dimensional consistency. These tools are not as versatile since they require to be adjusted at a changeover in machining types.

Comparison of Core Parameters of Mainstream Lathe Tools:

Tool Type	Main Application	Applicable Materials	Insert Cost (USD/Tool)	Advantages	Disadvantages
External Turning Tool	External cylindrical, conical, and end surfaces.	Mild steel, stainless steel, and aluminum alloys.	15-30	High flexibility and ease of handling.	Poor efficiency for hard curved surfaces.
Internal Turning Tool	Internal holes (round and stepped holes).	Stainless steel and structural alloy steels.	20-45	Suitable for internal structure machining.	Poor cooling and limited insert life.
Parting Tool	Parting and grooving.	Various metal materials.	8-20	High speed of cutting.	Prone to vibration and high tool breakage.
Threading Tool	Internal and external threads.	Structural steel and stainless steel.	25-50	Accurate threading with high precision.	Low efficiency and cuts multiple passes.
Forming Tool	Rotary surfaces of intricate shape (spherical and arc surfaces).	Mild steel and aluminum alloys.	30-60	High efficiency and stable precision.	Low flexibility and requires customization.

JS is able to recommend suitable tools based on your processing needs. Our internet CNC machining services provide machining of a wide range of parts, with simple ordering procedure. Choose JS and worry-free machining!

How To Make a Wise Choice? The Four Golden Decision Rules

After the understanding of mainstream tool types, follow these four rules to select the optimum suitable tool.

The Workpiece: The Beginning

The material's hardness, toughness, and thermal conductivity are the best reasons for tool selection.

For hardened steel HRC50+, use CBN inserts, for stainless steel, use TiAlN-coated carbide inserts, for titanium alloys with low thermal conductivity, use AlCrN-coated inserts. Incorrect tool use will cause the inserts to wear out too quickly and add to CNC machining price.

Tool Selection Table for Various Materials:

Working Material	Material Hardness (HB)	Recommended Tool Grade	Recommended Coating	Cutting Speed ​​Range (m/min)
Mild Carbon Steel	150-200	High-Speed ​​Steel, Carbide	TiN	80-150
Stainless Steel	200-300	Carbide	TiAlN	50-100
Aluminum Alloy	80-120	Carbide, PCD	(Uncoated)	200-500
High-Temperature Alloy (Inconel 718)	300-400	Ceramics, CBN	AlCrN	30-80
Titanium Alloy	250-350	Carbide, CBN	TiAlN	20-60

Machining Operation Type (The Operation): The Task Determines the Tool

Other operations demand other tools: For turning outside, choose an outside turning tool, for threading, choose a thread turning tool, for parting off, choose a cut-off tool.

Precision requirements also influence tool selection. For example, turning a high-precision outside diameter to Ra0.8μm would need a high-precision toolholder (grade H6) and ceramic/PCD inserts, while turning a normal outside diameter to Ra6.3μm can be achieved with a normal carbide insert.

Using an incorrect tool can impair both tool and workpiece, driving costs up.

Machine Capabilities: Avoid Having Your Tool Mismatched

Machine speed, power, and rigidity set the limit of tool performance. For instance, a 3000 rpm maximum speed machine is inappropriate for a 5000 rpm PCD insert (inefficient, subject to built-up edge). A 5kW machine is not suitable for an 8kW deep-cut tool (at the risk of overloading the spindle).

If JS recommends lathe tooling before it provides online CNC machining services, it takes into consideration machine tool specifications.

Cutting Fluid Strategy (The Coolant): Dry Cutting, Wet Cutting, or MQL?

Cutting fluid affects heat dissipation and lubrication, which in their turn affect insert life and part quality.

Comparison of Three Strategies:

Cutting Fluid Strategy	Working Principle	Advantages	Disadvantages	Suitable Tool Materials	Suitable Applications
Dry Cutting	No cutting fluid, heat-resistant tool.	No waste fluid cost, environmentally friendly.	Poor heat dissipation, low life of insert.	Ceramics, CBN, PCD	High-speed cutting, cutting aluminum alloy.
Wet Cutting	Jetting of cutting fluid (emulsion, cutting oil).	Efficient dissipation of heat, insert life long.	High cost of cutting fluid, waste fluid disposal required.	Carbide, high-speed steel	Medium and low speed machining, machining of stainless steel.
MQL	Jetting of a micro-mist (oil + compressed air).	Low cost, environmentally friendly, good lubrication.	Heavy initial equipment investment ($500-1000).	Carbide, ceramics	Machining of difficult-to-machine materials, precision machining to high levels.

JS understands how to match cutting tools with machining requirements. We can customize a solution based on your machine and material requirements, negotiate CNC machining prices, and deliver your order expeditiously. Choose JS!

Unusual Special Tooling Solutions You May Not Be Aware Of

In precision machining, the standard tools may not be sufficient. The below specialist solutions allow you to address these problems and gain a competitive edge in custom CNC machining manufacturing.

Custom Modular Boring Bars

Usable for boring deep holes (depth-to-diameter ratio > 5:1) or irregularly shaped holes, these are modules such as a cutter head, a tool bar, and an extension bar. These can be built in whatever combination is needed, eliminating the need for a single one-off monolithic boring bar.

Strengths are high flexibility and low cost of inventory, weaknesses are high initial cost (standard modules are between $1,000 and $3,000).

JS uses these bars to machine deep-hole parts, for example, hydraulic parts, to IT7 accuracy and 40% higher productivity than traditional boring bars.

PCD/CBN Welded Inserts

PCD welded inserts are made of PCD and can be used in aluminum alloys, copper alloys, and composite materials. They have a hardness of HV8,000-10,000 and 10-50 times carbide wear resistance. They cost $50-150 per insert and allow for high-precision and high-surface-quality machining (Ra ≤ 0.1μm). They are brittle and not suitable for ferrous metals.

CBN welded inserts contain CBN and are applied to hardened steel and high-temperature alloys. They have a hardness of HV4,000-6,000 and a wear resistance 5-20 times greater than carbide. They are $80-200 per insert and have good heat resistance (≤1300°C) and durability. However, they are expensive and subject to machining vibration.

Case Study: Transcending The Challenges Of Machining High-Temperature Alloy Impellers

Customer Pain Points

An aerospace firm was machining Inconel 718 high-pressure turbine impellers (Ra ≤ 0.8μm, IT6 grade) on standard TiAlN-coated carbide inserts. Insert life was as low as 15 minutes, and cutting speed was reduced to 30m/min. The surface roughness was also greater than required, resulting in an 8% scrap rate. CNC machining price per piece was as much as $1,200, and the firm was facing delay in delivery and potential claims.

JS's Solution

After reviewing the customer's current machining situation, JS designed a targeted solution:

• Improve tool material: SiAlON ceramic inserts with a temperature resistance of 1400°C and hardness of HV1500 (higher than cemented carbide's HV1200), suitable for machining Inconel 718.
• Optimization of geometric parameters: The rake angle was also changed between -5° and -3° (reduction of cutting resistance), the clearance angle between 8° and 10° (friction reduction), and the chamfer of the cutting edge was 0.2 x 15°.
• Improvement of cutting strategy: The 'high speed and small depth of cut' approach was used, increasing the cutting speed to 75 m/min from 30 m/min (increasing by 150%) and decreasing the depth of cut to 0.8 mm from 1.5 mm. MQL was used in order to facilitate heat dissipation and lubrication.

Results

After implementation, the solution posted outstanding results: insert life was extended to 75 minutes (+400%), with 6-8 tool changes per day (cost savings $300-400).

Part machining time was reduced to 1.2 hours (-52%), with production capability of 23 pieces a day, surface finish was reduced to 0.6-0.8μm, with <1% scrap rate (daily losses reduced by $500).

The price per piece of CNC machining was reduced from $1,200 to $780 (-35%), despite customer grievances and attracting new orders.

Invisible Costs: How To Increase Profit Margins With Lathe Tools?

The majority of businesses overlook the 'hidden cost' of tool change time, rework scrap, and machine downtime, typically more than the cost of the tool. The use of proper lathe tooling can in fact negate these expenses and increase profitability for CNC machining parts.

Tool Life Maximization and Tool Change Time Cost Saving

Choosing tool material and coatings with wear resistance (such as replacing TiN coating with AlCrN coating) can double insert life from 30 minutes to 60 minutes, cutting tool changes per day in half.

Tool change time can be reduced from 80 minutes to 40 minutes, saving $1,760 per month. It saves tool inventory and financial pressure.

Improving Machining Accuracy and Reducing Scrap and Rework Costs

By implementing high-precision tools and parameters (for example, the use of H6-grade toolholders in lieu of standard toolholders and PCD inserts), the scrap rate of IT7-grade parts is reduced to 1% from 5%, reducing rework expenses from $5,000 monthly to $1,000 monthly, a reduction of $4,000.

JS helped customers save significant dollars in scrap expense by recommending suitable tools when providing online CNC machining services.

Optimize Tool and Machine Matching to Minimize Downtime Costs

With mismatched tools, vibration and downtime are easy (e.g., using an 8kW, heavy-cut tool on a 10kW machine). An hour of downtime can cost around $80. Choosing the right tool (e.g., medium-force carbide tools for a 10kW machine) will reduce downtime.

Compare the monthly costs of various solutions in the table below:

Cost Type	Standard Tool Solution	Optimized Tool Solution	Monthly Cost Savings (USD)
Tool Change Time Cost	3,520	1,760	1,760
Scrap Rework Cost	5,000	1,000	4,000
Machine Downtime Cost	3,520	880	2,640
Total	12,040	3,640	8,400

FAQs

Q1: Is the most expensive blade the best?

Absolutely not.The core of 'the best blade' is to adapt to the current specific processing task,rather than simply looking at the price.For example, using expensive PCD blades to process steel parts not only fails to achieve performance,but also immediately leads to catastrophic failure due to material mismatch,resulting in cost waste and processing accidents.

Q2: How to determine if the blade needs to be replaced?

Four key signals can be used to determine:

• Whether the wear of the rear blade surface exceeds the standard.
• The surface roughness of the processed material has significantly deteriorated, with scratches or burrs appearing.
• Abnormal noise during cutting, such as piercing noise.
• The increase in cutting force is manifested as a significant increase in machine load.

Q3: Why did my new blade break quickly?

Apart from incorrect cutting parameter settings, the most common reasons are two-fold:

• The installation problem of the blade, such as residual impurities on the bottom surface causing loose fitting.
• The wear of the blade holder, and deformation of the blade holder can cause unstable clamping of the blade, leading to blade breakage.

Q4: Should I regrind the blade myself?

It is strongly not recommended to regrind them on their own. The precision coating and geometric parameters of this type of blade are professionally processed by the factory. Re grinding will damage the integrity of the coating and lead to edge accuracy deviation. After re grinding, the cutting efficiency and wear resistance of the blade are far different from new blades.

Summary

There is no such thing as a 'best' lathe tool, but merely the 'most suitable.' As when choosing utensils for foods, CNC machining parts require to be tailored to your individual needs. Proper lathe tooling can lead to increased quality and productivity of CNC machining parts as well as avoid unnoticed expense and boost profitability.

Still searching for the optimal tooling solution for your specific material and use? JS is your choice. Decades of on-site machining experience have given our technical experts the capability to provide free tool selection consultation and trial machining support to help you find the 'best fit' tooling for a silky-smooth and efficient machining operation every time.