A Set of Animations to Help You Understand Common Machining Methods
We use short animations to explain how each cutting method removes material, because motion is easier to grasp than a paragraph. This page is for design engineers and buyers who specify parts and want to judge which method fits a given feature. Read it and you can tell turning from milling, drilling from boring, and know when a part needs five axes.
Motion First, Vocabulary Second
Each section pairs one animation with the features that method can and cannot produce.
Turning: The Part Spins, the Tool Stays Still
In a turning animation the workpiece rotates and a single-point tool feeds along the axis. That is the whole idea. Because the part spins, the result is always a surface of revolution: shafts, bushings, pins, stepped diameters, threads, grooves and tapers. When a drawing shows a round cross-section on a centerline, turning is usually the cheapest way to make it.
Watch the tool path in the animation and you see two motions at once. The tool moves lengthwise to set the diameter, then radially to face a shoulder. On our lathes we hold ±0.005 mm on diameters and Ra 0.8–1.6 μm on a steady finish. Long slender shafts may need a steady rest or a second pass to control deflection.
Turning suits parts that are mostly round. A housing with one bore and six milled pads does not belong on a lathe alone. For that shape we either add a mill-turn center, which machines the round body and the flats in one setup, or split the job between a lathe and a mill.
Milling: The Tool Spins, the Part Moves
In a milling animation the cutter rotates and the worktable feeds the part past it. Flat faces, pockets, slots, steps and complex contours come from this motion. A three-axis mill moves X, Y and Z, so it reaches one face of the part per setup. That covers a large share of prismatic parts, and it is the fastest option when the geometry stays on accessible sides.
A four-axis mill adds a rotary table, usually Ø400 mm on our machines. The part can now be indexed to four sides without a second fixture. Holes on two faces, a slot crossing a corner, or a pattern that repeats every 90° become one setup instead of three. Fewer setups means fewer datum shifts and a smaller stack of tolerances.
Five-axis machining adds two rotary axes that move at the same time as the linear ones. The cutter can stay tilted to the surface, so it reaches undercuts, deep pockets and sculpted surfaces in one pass. We run 16 simultaneous 5-axis centers. For a part with compound angles or a contoured blade, five axes often remove the need for custom fixtures.
Not every part gains from more axes. A simple plate with holes and a chamfer is cheaper on a three-axis machine. Extra axes add programming time and setup checks that a flat part does not repay. Match the machine to the feature, not to the brochure.
Drilling, Reaming and Boring: Three Different Jobs
Drilling creates a hole with a rotating fluted tool. The animation shows the drill feeding straight down, and that straight line is also the limit. A standard drill leaves a slightly oversize hole with a helix mark inside. For a bolt clearance hole that is fine. For a bearing seat or a dowel pin, it is not.
Reaming follows drilling with a multi-edge tool that shaves a small amount of material. The hole becomes round, straight and to size, typically within a few thousandths of a millimeter. Reaming does not correct position. If the drilled hole is off center, the reamer follows it.
Boring uses a single-point tool on an adjustable head. The bar enters the existing hole and enlarges it while correcting position, size and straightness. Boring is slower than reaming, and it needs a rigid setup, but it is the method that fixes a hole that has drifted. Deep bores may need a boring bar long enough to reach, which limits the diameter you can cut.
A practical order for a precise hole is center drill, drill, then bore or ream. If you only need clearance, stop after drilling and save the cost.
Matching the Method to the Feature
Use this as a first filter before you send a drawing.
| Feature | Method | Typical tolerance | Watch out for |
|---|---|---|---|
| Round shaft, thread, groove | Turning | ±0.005 mm | Slender parts deflect |
| Flat face, pocket, slot | 3-axis milling | ±0.005 mm | One face per setup |
| Holes on four sides | 4-axis milling | ±0.005 mm | Rotary table size limit |
| Undercut, compound angle | 5-axis milling | ±0.005 mm | Programming time |
| Clearance hole | Drilling | ±0.1 mm | Oversize, helix marks |
| Precise pin hole | Reaming | ±0.01 mm | Follows drill position |
| Bore needing true position | Boring | ±0.005 mm | Needs rigid setup |
Common Questions
Why do animations help more than a written description of machining?
Machining is a motion, not a shape. A paragraph can say the tool orbits the bore, but a two-second clip shows the direction, the engagement and the clearance in one look.
For an engineer reviewing a drawing, that matters because the motion tells you which surfaces are cut in the same setup, and setup count drives both tolerance stack-up and cost.
How do I know if my part needs five axes?
Look for features the cutter cannot reach from a straight approach: undercuts, deep cavities with non-vertical walls, compound angles, or a sculpted surface.
If the same part can be reached by indexing it on a four-axis table, four axes is usually the lower-cost route. Send the model and we will tell you which one it is.
Can you machine a part from one piece instead of assembling several?
Often yes. A mill-turn center lets us cut the round body and the milled features in one setup, so a part that was three pieces welded together can become one solid.
That removes joints and the tolerance stack between them. It also changes the drawing, so we review the model before quoting rather than after.
What tolerance and finish can you hold across these methods?
We work to ±0.005 mm (±0.0002 in) on critical dimensions. Surface finish depends on the method and the tool path, from Ra 0.2–0.8 μm on a fine finish to Ra 1.6–3.2 μm as machined.
Inspection runs on 100% of parts before shipment, with reports available on request.
Which materials fit these methods?
Aluminium 6061, 7075, 2024 and 6082, stainless 303, 304, 316L and 17-4PH, steels such as 1045 and 4140, plus titanium TC4, Inconel and engineering plastics like POM and PEEK.
Harder and gummier materials change the cutting data and sometimes the method. Tell us the alloy with the model and we will flag any feature that needs a different approach.
What do you need to quote a part?
A 3D model and a 2D drawing with tolerances, plus the material, quantity and finish.
Quotation and free DFM analysis come back within 12 hours. Production can start within 24 hours, and parts ship in 3–5 days. Uploads stay secure and confidential, and we sign an NDA on request.
Send Us the Part, We Will Tell You Which Method Fits
Share your model and drawing. An engineer reviews the features and returns a quotation with DFM notes within 12 hours.
12-hour quote±0.005 mm100% inspection
