Finished-blade inspection takes place after heat treatment and final grinding, when the part has the geometry and hardness it will have in service. Depending on the order, the scope can cover critical dimensions against the approved drawing, hardness on a representative finished part and visual condition. Any buyer-facing record must be requested in the RFQ; its availability and exact scope are confirmed in the quotation.
Why finished-part inspection matters
Incoming-material and in-process checks address different risks from finished-part inspection. Heat treatment and grinding can change hardness, flatness and final dimensions, so measurements taken before those operations do not establish whether the finished part meets its acceptance criteria. The final inspection must therefore be made against the final geometry and the requirements agreed for the order.
For procurement, this is the check that maps directly to the part being delivered. The drawing and order confirmation must define what is accepted; the inspection scope should not be invented after manufacture.
What gets measured: dimensional check
The dimensional scope should focus on features that control fit and cutting function. It does not necessarily mean recording every dimension on every blade. Depending on the drawing and agreed sampling plan, relevant features may include:
Length, width, thickness (against drawing, to the specified tolerance).
Bevel angle (primary, and secondary where applicable).
Hole positions, slot positions, fixing geometry — anything that determines how the blade seats in the machine.
Flatness (on long blades, where heat-treat distortion is a real risk).
Edge straightness and parallelism (on slitting and shear blades).
Tolerances come from the approved drawing or another acceptance criterion expressly agreed in the order. If a necessary tolerance is missing, it must be clarified during quotation rather than assumed during inspection.
What gets measured: hardness
Where hardness verification is included in the order, HRC (Rockwell C) is measured on a representative finished part at a position that does not affect the cutting edge or functional seating area. The target, acceptance range, sampling and reporting scope are confirmed in the quotation.
Hardness is one measurable property of the finished blade. It shows whether the part falls within the hardness window selected for the required balance of wear resistance and toughness. It does not, by itself, prove service life or fitness for a particular application; those depend on the complete specification and operating conditions.
The target and acceptance range depend on steel grade, blade type and application. They are set during quotation and recorded in the order confirmation, not taken from a universal catalogue value.
What gets checked: visual condition and surface finish
Where visual and surface checks form part of the agreed inspection scope, they may cover:
Edge condition — visible chips, burrs or other departures from the agreed finish.
Surface finish — consistency with the specification and, where an Ra value is specified, the agreed value.
Coatings, if applied — visible coverage and edge condition against the coating specification.
What ends up in the inspection record
If an inspection record is requested and confirmed in the quotation, its fields are defined for that order. A record may include:
Batch number, drawing number, drawing revision.
Steel grade and, where material traceability forms part of the agreed scope, the heat number or material-certificate reference.
Dimensional measurements taken, with results against tolerance.
Hardness measurement on a representative finished part, with the agreed target and acceptance range.
Visual inspection notes.
Inspection date and the agreed approval field.
Documentation is not supplied automatically with every delivery. State the requirement in the RFQ. The quotation then confirms whether a pass-through EN 10204 3.1 mill certificate, dimensional record or hardness record is available and defines its scope.
What happens when a part does not meet spec
A result outside an agreed acceptance criterion is held for review. The disposition depends on the feature, tolerance and approved manufacturing route:
Rework may be possible where the deviation can be corrected without moving another feature outside tolerance or changing the intended function. The part must then be checked again against the applicable acceptance criteria.
Rework may be unsuitable where correction would affect geometry, material condition or function. Such a part cannot be released as conforming to the approved specification.
Three points to agree with the supplier
For procurement, three points should be agreed before the order:
Which dimensions or characteristics are subject to inspection, and what sampling applies.
Whether a material certificate, dimensional record or hardness record is required, and what identifiers or results it must contain.
What constitutes acceptance under the approved drawing and order confirmation. If a delivered part is suspected of nonconformity, preserve the part and operating evidence and follow the product-claim procedure.
Define inspection requirements before ordering
Finished-part inspection is useful only when the acceptance criteria are clear. A generic promise to “inspect every blade” tells a buyer less than a quotation that states the drawing revision, characteristics to be checked, sampling, acceptance limits and required documentation.
For a quotation, send the drawing, part number with revision and, where available, a worn sample of the part currently running in the machine. Include any documentation or inspection requirement in the RFQ.
Other posts in this series: inside our production floor, steel grades and where we use them, and what happens when you raise a complaint.