An OEM drill bit inspection should establish whether the delivered product matches the approved specification. Diameter and packaging checks alone do not demonstrate material grade or drilling performance. Split acceptance into identification, dimensional inspection, supporting material evidence and a controlled application trial. This checklist is intended primarily for twist drills; SDS and step drills require additional product-specific criteria.
Start with the drawing and intended hole
Confirm the tool family, material designation, nominal diameter, diameter tolerance, overall length, flute length, shank, point geometry and coating requirements. Define the workpiece and hole requirement separately. A drill’s nominal diameter is not a promise that every machine will produce a hole of exactly that size.
Use this inspection record
| Check | Evidence to retain |
|---|---|
| Lot and specification | Order, drawing revision, carton IDs and sampled tool IDs |
| Dimensions | Actual readings, measuring locations, instrument and acceptance limits |
| Cutting geometry | Point and lip inspection against the agreed drawing |
| Runout | Holding method, measurement location and result |
| Material and coating | Agreed certificates or test reports linked to the lot |
| Application trial | Workpiece, machine, settings, hole measurements and tool condition |
| Packing | Count, size labels, edge protection and approved branding |
Measure geometry with a defined method
Inspect the point, cutting lips and visible edge condition using suitable magnification or measuring equipment. Compare symmetry and angles with the approved design rather than assuming every twist drill should look identical. Split points and other point modifications require their own reference. State where diameter is measured; tool geometry and back taper can make readings at different locations non-equivalent.
For runout, specify the fixture, shank engagement and measurement point. A reading affected by a damaged chuck or dirty seating is not reliable evidence about the drill alone. Record the measurement method alongside the number and assess it against an agreed limit.
Do not identify material by color
A gold or dark surface is not sufficient evidence of substrate grade, cobalt content or coating identity. Agree the documentation and any verification testing needed for the order. If hardness or composition must be tested, define the applicable method and acceptance basis with a competent test provider. Do not substitute a visual inspection for that evidence.
Keep the trial drilling reproducible
Use a recorded material grade, thickness, machine, holder and permitted operating conditions. Record coolant or lubrication, entry and exit conditions, total holes and accepted holes. Measure the hole features relevant to the drawing, which may include size, position or exit burr. Do not prescribe a universal tolerance for every drill family or application.
If the sample trial ends before wear reaches the agreed limit, report the completed hole count as an observation, not demonstrated full life. A tool that passes one trial should still be tied to a batch inspection plan.
Check the shipment as the customer will receive it
Verify assortment counts, metric or imperial labels, tool markings and packaging artwork. Check that handling and transport protection prevent cutting edges from contacting hard neighboring parts. Identify sampling scope clearly and separate confirmed defects from untested characteristics. Define who can approve rework or a deviation before dispatch.
Use the OEM sourcing guide, runout guide and coating color guide alongside this checklist. Send the drawing, material requirement, packaging plan and intended application to Wryno when discussing inspection requirements.