Essential terms
| Term | Plain-English meaning | Why it matters |
|---|---|---|
| BOM | Bill of materials or parts list | Controls IDs, materials and quantities |
| CNC | Computer numerical control | The machine follows prepared instructions; it does not infer design intent |
| Datum | Chosen reference edge, face or point | Important positions are measured from it |
| DXF | Common CAD exchange format | Units, version and geometry still need checking |
| Engraving | Shallow line or recessed detail | Cutter, depth and material affect legibility |
| Dogbone | Intentional corner relief | Helps a square-ended part clear a routed internal radius |
| Nesting | Arranging parts on stock | Affects material use, spacing and hold-down |
| Recessed area that does not cut through | Needs a boundary, depth and reference face | |
| Profile | Intended outer boundary of a part | Defines the main cut outline |
| Prototype | Physical version used to answer design questions | Reduces risk before repetition |
| Rebate/rabbet | Step or recess, often at an edge | Can locate another panel or component |
| Revision | Controlled version of a part | Prevents production from an obsolete file |
| Tab | Small uncut bridge holding a part temporarily | Affects separation and edge cleanup |
| Tolerance | Permitted variation | Must be separated from functional fit |
| Toolpath | Programmed path for a cutter | Influences operations, time and result |
| Vector | Geometry represented as paths | Can describe scalable cut geometry |
Use terms with dimensions
Vocabulary does not replace a marked drawing. A “pocket” still needs depth; a “slot” needs width, length and end shape; a “press fit” needs material and behaviour defined.
Geometry and file terms
Vector: geometry described by coordinates, lines and curves rather than pixels. Vectors can define scalable paths, but still need correct units, closure and operation meaning.
Raster image: a grid of pixels, such as a JPG or PNG. Useful for photographs and visual references; normally not an exact cut path.
DXF: an exchange format commonly used for CAD lines, arcs and polylines. A DXF is not automatically clean, scaled or production-ready.
SVG: a web-oriented vector format. It can contain paths, text and visual effects. Decorative effects may not translate directly into machining geometry.
Polyline: connected straight or curved segments treated as one object. Closed polylines are often useful for profiles and pockets.
Spline: a mathematically smooth curve controlled by points. Some exports approximate splines with many segments, so check the result.
Closed path: a boundary whose last point connects to its first. Usually needed to describe an enclosed profile or pocket region.
Open path: a line that has distinct start and end points. Often suitable for engraving, but ambiguous if a closed cut was intended.
Node: a control point or vertex in vector geometry. Excessive nodes can make traced paths noisy and difficult to edit.
Scale 1:1: file geometry is stored at intended real size in stated units. Print scale and screen zoom are separate.
Datum: a reference edge, face, centre or point from which important dimensions are located.
Revision: a controlled version of a part or release package. It should identify what changed and which version is approved.
Machining operation terms
Profile: a toolpath following the outside or inside boundary of a shape, often to separate a part or opening.
Pocket: an area cleared to a stated depth without cutting through the sheet.
Through-cut: an operation intended to pass through the material.
Blind feature: a pocket, hole or recess that stops at a depth.
Engraving: shallow line or area machining used for marks, text or decoration.
Toolpath: the programmed route and motion used by the cutter. It is manufacturing data derived from reviewed geometry and operations.
Cutter compensation: placing a cutter centre inside or outside nominal geometry to account for cutter radius. It should not be hidden in the design file without agreement.
Step-down: dividing a deep operation into several depth passes. It is a machining choice, not permission to draw arbitrarily deep narrow features.
Finishing pass: an additional pass intended to improve final dimension or surface. Suitability depends on the job.
Tool change: switching to another cutter and completing the associated setup/verification. It adds more than the physical swap time.
Spindle: the powered unit that rotates the cutter.
CAM: software/process used to turn geometry and operation decisions into toolpaths. CAM is not a substitute for approved design intent.
Cutter and feature terms
Cutter diameter: width of the cutting tool. It limits minimum internal radii and access to narrow features.
Cutter radius: half the cutter diameter geometrically. Real results also depend on setup, wear, deflection and material.
Internal radius: rounded material remaining in a concave corner because the cutter is round.
Dogbone: intentional corner relief extending beyond a nominal internal corner to clear a square mating part.
T-bone: corner relief positioned along one adjacent edge rather than diagonally.
Island: material intentionally left inside a pocket or between removed areas. Small islands may be fragile.
Minimum feature: the smallest width, gap, radius or detail under review. There is no single universal minimum independent of depth/material/tooling.
Aspect ratio: relationship between feature depth and width/tool diameter. Deep narrow features are often more difficult than shallow ones of the same width.
Material and holding terms
Nominal thickness: product label such as 12 mm or 18 mm. It is not an exact measurement of every sheet.
Actual thickness: measured thickness of the specific material at recorded points and conditions.
MDF: medium-density fibreboard. Its faces and routed edges behave differently during finishing.
MR MDF: moisture-resistant MDF. “Moisture resistant” is not the same as waterproof or suitability for every damp application.
Structural plywood: plywood sold to a structural specification. Machining it does not validate a finished product’s structural design.
Workholding: the method used to keep sheet and parts controlled during cutting.
Nest: arrangement of parts within stock material for machining.
Tab: small bridge left to connect a part to surrounding material until separation. It usually needs cleanup.
Onion skin: thin uncut layer left temporarily to help hold parts before a final/release step.
Waste area: material not forming the final part. It is not automatically available for screws/clamps unless agreed.
Fit and assembly terms
Tolerance: permitted variation around a stated requirement, with a defined measurement basis.
Clearance fit: intentional space between mating parts so they assemble without interference.
Interference or press fit: mating parts overlap dimensionally under specified conditions and assemble through deformation/force. Wood-material behaviour requires testing.
Transition fit: variation can produce either slight clearance or interference.
Tolerance stack: combined effect of material, machining, finish and mating-component variation on an outcome.
Coupon: small labelled test containing one or more candidate features, such as slot widths.
Prototype: representative part or assembly made to answer defined design/production questions before a batch.
Tab-and-slot: projecting feature entering an opening for location or assembly.
Dado: groove receiving another panel or component, often used for shelves/dividers.
Rabbet or rebate: edge recess allowing another part to overlap or sit flush.
First-off: initial production part checked before continuing a batch.
Go/no-go gauge: physical check showing whether a feature is within an approved functional range.
Quality and commercial terms
Feasibility review: check of whether the proposed material, geometry, operations and scope appear suitable for quotation/development. It is not product certification.
Critical characteristic: feature or requirement whose failure has an important functional consequence.
Acceptance criteria: agreed observable conditions used to decide whether supplied parts meet scope.
Concession: written acceptance of a defined non-conforming condition for stated parts/quantity. It should not silently change future requirements.
Bill of materials: list of part IDs, revisions and quantities needed for a product or batch.
Part ID: stable code identifying one distinct component.
Setup: preparation needed to hold material, establish references, prepare tools/programmes and verify a machining operation.
One-off: one part or one job, usually carrying setup effort that is not spread across many units.
Small batch: repeated quantity under one controlled release. The exact commercial range is job-dependent, not a universal number.
Blank: CNC-cut part supplied for another party to finish, personalise, assemble or package.
Handoff state: agreed condition in which responsibility transfers, such as machined raw part, sanded blank or finished assembly. Never infer it from “CNC cut.”
Use terms in a complete instruction
Terminology helps only when connected to dimensions and intent. “Add a pocket” is incomplete. “Pocket on Face B, 6 mm deep from that face, to locate the supplied hardware without protrusion” is reviewable. “Press fit” is incomplete. “Painted divider should assemble by hand and remain removable; prove with a finished coupon” describes behaviour.
When unsure of a term, describe the physical result in ordinary language and mark the uncertainty. That is safer than selecting a technical word that suggests a decision you did not intend.
Use the terms in a project brief
- Units accompany dimensions.
- Face and depth accompany blind operations.
- Fit term includes desired behaviour and condition.
- Material term includes actual product/basis where important.
- Part ID and revision accompany production files.
- Safety/compliance language remains separate from machining terms.
- Unknowns are labelled rather than disguised with jargon.
Safe boundary
These definitions explain how terms are used in this guide library. They are not universal engineering specifications, machine instructions or legal definitions. Where a standard, hardware manufacturer or regulated use defines a term more strictly, that authoritative context takes priority.
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