DRAWING DETAILS / CNC MACHINING INSIGHTS
A chamfer and a radius can both remove a sharp edge, but they do not communicate the same geometry or assembly intent. When an edge affects clearance, sealing, insertion or appearance, the drawing should identify the actual requirement rather than relying on a general edge-break note.
Use the edge geometry that matches the function
| Edge condition | Typical purpose | What to state |
|---|---|---|
| Chamfer | Creates a defined angled entry or clearance edge. | Location, size and angle when the edge geometry is functional. |
| Radius | Creates a rounded transition for a mating, contact or external profile. | Location and radius value, with the related interface if relevant. |
| General edge break | Removes an unwanted sharp edge without prescribing a functional profile. | Apply the general note only where no individual edge geometry is required. |
Do not use a general deburring instruction to stand in for a specific chamfer or radius that changes part fit. A functional edge should be shown and called out directly.
Show how the edge meets the mating part
An entry chamfer may guide a pin, screw or inserted component. A radius may create clearance at a mating corner or protect a contact surface. If the purpose is not visible in the individual part, share the relevant mating geometry in the RFQ package.
Our assembly-fit guide explains how to provide mating-part context so a reviewer understands an interface without guessing its function.
Separate functional geometry from deburring
Deburring removes undesirable sharpness; it does not automatically establish an angle, a radius or a controlled feature size. For a general edge condition, a clear drawing note can be appropriate. For a particular opening, sealing face, alignment feature or visible exterior edge, specify the needed geometry at that location.
See our guide to deburring and edge breaks for a useful distinction between a general finishing requirement and an individually defined edge feature.
Connect the edge to inspection only where needed
If the chamfer or radius controls assembly, show which dimensions matter and which reference surface defines the requirement. If it is cosmetic or a general safety edge, avoid creating a vague inspection expectation that is disconnected from function.
Our CNC inspection requirements guide can help buyers identify critical drawing-defined features before production is released.
Questions to answer before the RFQ
- Does this edge guide, clear, seal, locate or merely remove sharpness?
- Does the drawing need a chamfer, a radius or only a general edge-break note?
- Which face or mating part makes the edge functional?
- Is the edge on one side or both sides of the part?
- Does the feature need any inspection attention because it affects fit?
Make the edge intent clear
ExactMach coordinates drawing-defined CNC milling, CNC turning, prototypes and custom parts around Shenzhen and Dongguan for international orders. Clear chamfer and radius callouts help the manufacturing review understand the released edge requirement before production begins.