Updated 6 September 2026
24 checks before your CNC machining quote
Review geometry, threads, tolerances, finishes and drawing control before sending a machining RFQ. Use this checklist to identify questions for your designer and manufacturing partner.
This is a review aid, not a universal machining limit or acceptance specification. Feasibility, inspection, price and lead time are confirmed against the approved drawings, material and quantity. Sheet metal and casting need additional process-specific checks.
Geometry and access
Thin walls
Identify thin walls and unsupported spans. Review stiffness, workholding and distortion for the selected material. Mark areas where ribs or thickness changes are acceptable.
Internal corners
Show the smallest acceptable internal radius and the mating part clearance. Ask for a process review where a sharp internal corner is functionally necessary.
Deep holes
Specify diameter, full-diameter depth, through or blind condition, and entry direction. Review tool reach and chip removal before fixing the process.
Small features and reach
Check whether the tool and holder can reach each small feature. Include pocket depth and adjacent geometry; feature size alone does not establish feasibility.
Undercuts and side features
Identify side holes, undercuts and inaccessible faces. Discuss extra setups, suitable tooling or alternative processes for the actual geometry.
Threads and fasteners
Thread engagement
Specify required full thread depth separately from drilled depth. Confirm engagement against the mating fastener, material and load; agree tool clearance for blind holes.
Thread callouts
State thread standard, size, pitch, tolerance class and handedness where relevant. Resolve missing or conflicting callouts before manufacture.
Small threads
Identify small or difficult threads and required gauges. Tapping or thread milling is selected for the material, size and access; do not assume one method fits every thread.
Counterbores and countersinks
Specify the fastener or head standard, seat diameter, depth and included angle as applicable. Include flushness requirements on cosmetic or mating surfaces.
Threaded inserts
Identify the insert manufacturer, part number, installed length and installation requirements. Use that insert supplier’s preparation dimensions rather than a generic tap-hole size.
Tolerances and inspection
General tolerances
State the applicable drawing standard and general tolerance requirements. Clarify their scope; missing dimensions and unspecified geometry still need review.
Critical dimensions
Identify fit, sealing and assembly dimensions and explain their function. Agree acceptance criteria and inspection coverage; unmarked features are not automatically non-critical.
Datums
Define functional datums and the drawing convention used. Resolve an incomplete datum reference frame with the designer instead of guessing the assembly intent.
Geometric tolerances
Specify the required control, tolerance zone and datum references. Position, profile and dimensional tolerances are not interchangeable; confirm what the inspection must establish.
Form and orientation
Specify flatness, perpendicularity or parallelism only where function requires them. Review size, material, heat treatment, setups and measurement conditions for feasibility.
Finish and appearance
Surface texture
Identify the faces requiring a defined surface texture and the applicable parameter and value. Separate sealing or sliding requirements from cosmetic appearance.
Edges and burrs
State chamfer or edge-break limits and identify edges that must remain sharp. Include internal intersections, cleanliness and assembly requirements where relevant.
Appearance and anodizing
Identify cosmetic faces, colour references, masking and coating requirements. Agree the sample and acceptance method when matching appearance across parts or batches matters.
Plating and heat treatment
Specify material condition, treatment standard and coating requirements. Where embrittlement prevention is required, agree the applicable qualified process; no universal bake cycle is assumed.
Drawing package and revision
Drawing and CAD package
Supply a readable dimensioned drawing and available 3D data. Identify which document governs each requirement and resolve any mismatch before production.
Views and sections
Add sections or detail views wherever internal geometry or small features would otherwise be ambiguous. Ensure dimensions and notes remain readable at normal viewing scale.
Units and projection
State units and projection method explicitly. Check imported CAD scale and any mixed-unit dimensions; do not infer projection solely from the destination country.
Assembly and BOM
For assemblies, provide part numbers, quantities, materials, finishes and relevant mating requirements. Identify purchased items and who supplies them.
Revision and approval
Put revision identifiers on drawings, models and the BOM. Identify the approved production revision, retain superseded records as required, and keep obsolete files out of the active job package.
Three things to prepare before requesting a quote
Material and quantity
State the exact grade, condition, initial quantity and expected repeat demand. Mark undecided items as open.
Drawing and acceptance
Keep CAD and PDF at the same revision. Identify critical dimensions, datums, finish and inspection records.
Confidentiality and delivery
Agree NDA and transfer requirements before sharing protected files. Give the delivery destination and requested date; shipping and tax responsibilities are confirmed separately.
Frequently asked questions
Does passing the checklist guarantee manufacturability?
No. The checklist identifies review topics. The actual part still needs assessment against geometry, material, quantity, inspection and delivery requirements.
Can I share the PDF with my team?
Yes. Download it directly without registration. Keep the version date and source link when sharing so colleagues can find the current guide.
What should I send with an RFQ?
Include the drawing revision, available CAD data, material, quantity, critical requirements and delivery destination. Discuss an NDA before sending confidential drawings if needed.
Continue your review
Further technical reading
Equipment limits and figures in third-party references are not specifications for our factory.
Discuss your drawing and request a quoteShipping method, freight, duties, taxes and customs arrangements are confirmed by email for each order.