milling

Threading a hole sounds simple, until you’re deciding between thread milling and tapping. Both methods are staples in CNC machining and manual operations, but they serve different purposes, machines, and tolerances. Whether you're threading aluminum, stainless steel, or titanium, choosing the wrong method can mean broken tools, scrapped parts, or wasted hours.   Let’s break down the real differences between thread milling vs tapping, when to use one over the other, and how to choose the right tool for your part. What is Tapping?   Tapping is the traditional method of creating internal threads by driving a tap, a hardened cutting tool, into a pre-drilled hole. It’s fast, easy to set up, and widely used in manual and CNC operations.   There are three common types of taps: ● Hand taps – used manually with a T-handle ● Spiral point taps – best for through holes ● Spiral flute taps – best for blind holes   Taps are typically specific to one thread size and pitch, which makes them convenient but rigid in flexibility.   What is Thread Milling?   Thread milling, on the other hand, uses a rotating tool called a thread mill to cut threads with a helical interpolation motion. The tool enters the hole and follows a spiral path to form the thread, using a CNC program to control pitch and depth.   There are three types of thread mills: ● Single-point thread mills – extremely flexible for custom threads ● Multi-form thread mills – cut the full profile in one pass ● Indexable thread mills – ideal for large threads or production runs   Thread milling may require more programming and setup time, but it shines in areas tapping simply can't reach.   Thread Milling vs Tapping: Head-to-Head Comparison   Let’s stack up thread milling vs tapping in the areas that matter most: Thread Milling and Tapping in Different Materials   When working with softer materials like aluminum or mild steel, tapping is fast and rarely problematic.   But when dealing with: ● Stainless steel ● Tool steel ● Superalloys   …thread milling provides better tool life and reduces the risk of tool breakage. This makes it a smart choice for aerospace, medical, and high-precision industries.   CNC Programming Differences   Tapping usually relies on a simple cycle (G84 for right-hand, G74 for left-hand tapping). Easy to program, minimal variables.   Thread milling, on the other hand, requires: ● Circular interpolation (G02/G03) ● Depth control ● Helix angle programming   While this adds complexity, modern CAM software and CNCs make it increasingly easier.   Tool Life and Cost Considerations   Taps wear out quickly in hard materials and can break, especially in blind holes with poor chip evacuation.   Thread mills, although more expensive upfront, last longer and are more forgiving, especially if you’re threading near the bottom of a hole. Plus, if a thread mill breaks, you typically don’t lose the entire part.   Is Thread Milling Better Than Tapping?   It depends on your application.   Tapping wins when: ● You're working in high-volume production ● Thread size and material are standard ● Speed and cost-per-hole are critical   Thread milling is better when: ● You're threading expensive or difficult materials like Inconel or titanium ● You need flexibility in thread sizes or depths ● You want to avoid breaking taps in blind holes ● You're using CNC machines capable of helical interpolation   So, is thread milling better than tapping? In terms of flexibility and safety, yes. But in terms of speed and simplicity, tapping still holds the crown for everyday work.   At KESO, we specialize in precise, reliable threaded parts, no matter the size, material, or threading method. Whether you need help programming a thread milling cycle or want bulk tapping production, we’re here to help.   Upload your design file and get a free quote here, we’ll recommend the best process for your job.   Final Word: Which One Should You Use?   Use tapping when: ● You need speed and low cost ● You’re working on large batches with consistent threads ● You have limited CNC capabilities   Use thread milling when: ● You're working with tough or expensive materials ● Flexibility, precision, and thread quality matter ● You're threading blind holes or varying thread diameters   Pro tip: If you’re threading critical parts, test both methods. A single broken tap can cost more than investing in a thread mill.                                  

  Surface quality is a key indicator for measuring the precision of CNC machined parts. It involves three aspects: roughness (microscopic unevenness), waviness (macroscopic periodic unevenness), and texture (machining tool path direction).   I. Surface Processing Types (How to Achieve)   Different processing operations and strategies can achieve different surface finishes. The following is arranged in order from coarse to fine. Typical achievable roughness (Ra) description of processing types and applicable scenarios Rough machining of 12.5 μm - 3.2 μm uses a large cutting depth and high feed rate to quickly remove the material, leaving obvious tool marks and a poor surface. When the parts are initially formed, machining allowances are reserved for non-critical surfaces. Semi-finishing is 3.2 μm - 1.6 μm to prepare for finishing, remove the marks of rough machining, and ensure an appropriate allowance for finishing. The final processing of most non-mating surfaces, installation surfaces, etc. Conventional finishing of 1.6 μm - 0.8 μm adopts small cutting depth, small feed rate and high rotational speed. The knife marks are visible to the naked eye but smooth to the touch. The most common precision requirements are used for static mating surfaces, sealing surfaces, bearing housings, etc. High-precision finishing of 0.8 μm - 0.4 μm requires optimized parameters, sharp cutting tools, high-rigidity machine tools and effective cooling. The surface is extremely smooth. Dynamic mating surfaces, hydraulic cylinder walls, and high-load bearing surfaces. Superfinishing of 0.4 μm - 0.1 μm requires the use of single crystal diamond tools, extremely high machine tool accuracy and a stable environment (constant temperature). Optical components, precision instrument surfaces, silicon wafer processing. Manual polishing/grinding < 0.1 μm: Remove the knife marks by hand or mechanical means such as sandpaper or oilstone to achieve a mirror-like effect. Appearance parts, mold cavities, surfaces of food and medical equipment. Ii. Symbols, Charts and Annotations (How to Specify)   Engineers clearly specify the requirements on the drawing through surface roughness symbols.   1. Basic symbols   Explanation of symbol meanings √ Basic symbols indicate that the surface can be obtained through any process and are meaningless to use alone. Youdaoplaceholder0 is the most commonly used to remove materials. It indicates that the surface is obtained by removing the material through processing methods such as milling, turning and drilling. "Non-removal of material refers to surfaces formed through casting, forging, rolling, etc., which do not require processing."   2. Complete annotation (taking the removal of material symbols as an example) :   ` ` ` [a] - Roughness parameters and values (such as Ra 0.8) [b] - Processing methods (such as "milling ") [c] - Texture direction symbols (such as "=") [d] - Machining allowance (e.g. 0.3mm) [e] - Sampling length (e.g. 0.8mm)     3. Common Annotation examples:   · ⌝ Ra 1.6: the most common form. It indicates that the maximum surface roughness Ra value is 1.6 μm by the method of removing the material. · ⌝ Ra max 3.2: the Ra value shall not exceed 3.2 μm. · ⌝ Ra 0.8 / Rz 3.2: both Ra and Rz values are specified. · ⌝ Rz 10 N8: marked with "N grade", N8 corresponds to Rz 10μm.   4. Surface texture direction symbol: The texture direction is crucial for sealing and motion coordination. The symbol is marked on the extension line.   Schematic diagram of symbol meaning The tool path direction of the projection plane parallel to the view is parallel to the boundary of the plane it is on Perpendicular to the projection plane of the view, the direction of the tool path is perpendicular to the boundary of the plane where it is located The X-cross texture tool path is in a cross shape (such as milling back and forth) M multi-directional without a dominant direction (such as point milling) The C approximate concentric circles are produced by turning R-approximate radiation is produced by end face turning or end face milling. Iii. Surface Roughness Testing (How to Verify)   After processing is completed, professional instruments should be used for objective measurement to verify whether it meets the requirements of the drawings.   1. Contact profilometer (needle tracing method)   · Principle: This is the most classic and authoritative method. An extremely sharp diamond probe (with a tip radius of approximately 2μm) gently slides across the surface of the workpiece. The vertical displacement is converted into an electrical signal, which is then amplified and calculated to obtain parameters such as Ra and Rz. · Equipment: Surface roughness measuring instrument. · Advantages: Precise measurement, compliance with national standards, and capable of measuring various complex shapes. · Disadvantages: It is a contact measurement, which may scratch extremely soft materials and has a relatively slow measurement speed.   2. Non-contact optical profiler   · Principle: By using techniques such as light interference, confocal microscopy or white light scattering, a 3D surface topography is constructed by analyzing the reflection of light on the surface, thereby calculating the roughness. · Advantages: Fast speed, no scratching of workpieces, and capable of measuring extremely soft materials. · Disadvantages: Sensitive to surface reflective characteristics (difficult to measure transparent and highly reflective materials), and the equipment is usually more expensive.   3. Compare Sample Blocks (Quick and Practical Method)   · Principle: A set of standard sample blocks with known Ra values are used. Through fingernail touch perception and visual comparison, the surface to be measured is compared with the sample blocks to estimate the approximate roughness range. · Advantages: Extremely low cost, fast and convenient, suitable for workshop sites. · Disadvantages: It is highly subjective and has poor accuracy. It can only be used for rough estimation and preliminary judgment and cannot be used as the basis for final acceptance.   Suggested measurement process   1. Drawing analysis: Clearly identify the parameters to be measured (such as Ra) and their theoretical values. 2. Clean the surface: Ensure that the tested area is free of oil stains, dust and burrs. 3. Selection method: · Quick online check → Use comparison blocks. · Final quality inspection → Use a contact profilometer. For soft or mirror-finished workpieces, consider non-contact optical measurement. 4. Conduct measurements: Take the average of multiple measurements at different positions on the surface to ensure the representativeness of the results. 5. Recording and Judgment: Record the measured values and compare them with the requirements of the drawings to make a judgment of qualified or unqualified.   Only by combining the correct processing technology, clear drawing marking and scientific measurement verification can the surface quality of CNC parts be fully controlled.  

Helps the tool shear copper instead of smearing it Cutting Edge Sharp, polished edge Prevents built-up edge and keeps surfaces smooth Lubrication Cutting oil or silica-based coolant (milk-like viscosity) Keeps chips from sticking and controls heat Chip Clearing Air blast or mist Prevents burrs and scratches from recut chips Feeds/Speeds High RPM, steady feed Keeps material cutting clean rather than rubbing   Getting these basics right often means fewer burrs, less heat, and cleaner parts straight off the machine. If you want a broader breakdown across different metals and plastics, check out our full guide on feeds and speeds in CNC machining. It'll give you a reference point when tuning copper-specific settings.     Fixtures, Workholding & Design Tips for Machining Copper Soft metals like copper don't forgive sloppy setups. Strong workholding and smart design choices are key in copper CNC machining. Use this as a checklist:   Area Best Practice Why It Matters Tool Stick-Out Keep it minimal; seat tool deep in collet Reduces vibration and chatter Collet Depth Maximize depth for small tools Improves stability and accuracy Wall Thickness Minimum ~0.5 mm Thinner walls flex or deform under load Deep Pockets Avoid unsupported features Copper tends to chatter and deflect Part Support Use soft jaws or custom fixtures Holds copper without marring the surface   These tweaks help maintain dimensional accuracy and surface quality while avoiding tool wear and wasted setups.     Common Pitfalls & Troubleshooting (Envato)   Machining copper isn't all smooth sailing. Even with the right setup, there are a few things that trip people up: Tool Wear: Copper loves to stick to the cutting edge, building up until your tool is dull. Expect to swap tools more often than with aluminum. Built-Up Edge: That gummy behavior creates adhesion on the tool, which kills surface finish. The fix? Keep tools razor-sharp and don't skimp on coolant. Work-Hardening: If chips aren't cleared, they get cut twice, hardening the surface and making the next pass harder. Air blast or flood coolant helps keep chips moving out of the cut.   The takeaway: good tooling, constant chip evacuation, and sharp cutters are your best friends in CNC copper work.     CNC Copper Machining vs Alternative Methods (Envato)   Copper parts can be made a lot of ways, EDM, laser cutting, even chemical etching. But for precision shapes and tight tolerances, CNC copper machining often wins. Here's the breakdown:   Method Strengths Limitations Best Use Case CNC Milling/Turning High precision, smooth finishes, fast turnaround Tool wear, burrs if chips aren't managed Prototypes, electrical connectors, precision blocks EDM (Electrical Discharge Machining) Great for very fine features, hard-to-cut shapes Slower, higher cost Intricate cavities, sharp internal corners Laser Cutting Fast for 2D profiles, no tool wear Struggles with thicker stock, heat-affected zones Flat parts, brackets, simple outlines Chemical Etching Good for ultra-thin sheets Limited thickness, slower process PCB foils, thin copper shims   For most parts, machining copper on CNC gives you speed, repeatability, and a finish that usually needs little to no extra work. EDM and other methods shine when geometry is extreme, but milling covers the majority of practical jobs.     Applications & Why You'd Choose CNC Copper Machining (Envato)   Copper's unmatched electrical and thermal conductivity makes it the go-to choice when performance matters. CNC machining allows you to shape this tricky but valuable metal into parts with tight tolerances and clean finishes.   Common applications include: Busbars & power distribution parts – where low resistance is non-negotiable. Heat sinks & thermal plates – copper's ability to pull heat away keeps electronics running cool. RF connectors & antennas – precision-machined copper components ensure signal clarity. Valve bodies & fluid components – corrosion resistance plus machinability makes copper ideal. Electrodes for EDM – copper's conductivity supports efficient spark erosion.   In short, if the job requires fine details, excellent conductivity, and high reliability, copper CNC machining beats casting or forming every time.   Copper's ability to deliver both fine detail and reliable conductivity also makes it a quiet hero in medical tech. We've covered more on that in our piece about CNC machining for medical devices.   At Keso, we've helped engineers and manufacturers turn raw copper stock into finished parts, from custom busbars to intricate RF connectors. You can get started with a free quote, and in some cases, parts cost as little as $1.