An H22 tapered button bit should not pass pre-shipment inspection merely because its outside diameter and quantity look correct. The buyer must confirm the approved variant, taper interface, gauge diameter, carbide-button condition, flushing passages, body finish, markings and packaging against a controlled specification. The inspection record should also identify the lot and show which characteristics were checked on every unit versus by sampling.
The central procurement risk is interface ambiguity. “H22” identifies the hexagonal drill-steel family; it does not, by itself, prove the taper angle or complete bit-to-rod fit. Buyers should therefore treat taper confirmation and a physical fit check as separate acceptance items. This guide provides a practical H22 tapered button bit pre-shipment inspection sequence without inventing universal tolerances that belong on the buyer-approved drawing.
Quick answer: the minimum acceptance gate
Before release, verify five things in order:
- Identity: the lot matches the purchase order, approved drawing and variant list.
- Interface: the taper specification and socket fit match the approved H22 tapered rod system.
- Dimensions: head diameter, body features and other controlled dimensions meet drawing tolerances.
- Functional condition: carbide buttons are correctly seated, the steel body is sound and flushing passages are open.
- Lot protection: quantity, segregation, corrosion protection and export packaging preserve the accepted condition.
A pass/fail decision should cite the revision-controlled acceptance document. If a supplier cannot identify the drawing revision or approved comparison sample, the lot is not ready for final acceptance even when visual workmanship appears good.
Define the inspection basis before opening the cartons
| Control document | What it should define | Why it prevents disputes |
|---|---|---|
| Purchase order | Item code, quantity, agreed variant, packing and required records | Connects inspection evidence to the commercial order. |
| Approved drawing or specification sheet | Taper, nominal dimensions, tolerances, button layout, flushing arrangement and marking | Provides objective acceptance criteria instead of visual opinion. |
| Approved sample or reference unit | Physical geometry and fit reference where contractually agreed | Helps resolve features that photographs or short descriptions cannot control. |
| Inspection plan | Characteristics, instruments, sample sizes, defect classes and disposition rules | Prevents the supplier from choosing the easiest checks after production. |
| Packing specification | Unit separation, corrosion protection, carton or crate strength and labels | Keeps conforming bits from being damaged or mixed during transport. |
Do not accept catalog language such as “H22 compatible” as a replacement for the controlled interface definition. The inspection team needs the exact taper and the dimensions or reference gauges agreed for that order.
What H22 does—and does not—confirm
H22 commonly describes a 22 mm hexagonal drill-steel section used with pneumatic rock drills. OEM product information also shows H22 × 108 mm as an available shank format for certain pneumatic drills. However, the shank format at the rock drill and the tapered connection at the bit end are different interfaces.
Consequently, an H22 rod or bit description does not automatically establish a 7°, 11° or 12° taper. Nor does it prove that two suppliers use the same socket depth, contact location or dimensional tolerance. The buyer must name the required taper and approved mating system. If the order is being converted from an existing source, provide a controlled drawing or an unworn reference assembly rather than relying only on a used bit.
For a detailed compatibility check, see 7° vs 11° vs 12° Tapered Drill Rods and Bits.
Step 1: verify lot identity, quantity and variant segregation
Start with traceability before measuring individual bits. Record the supplier lot or batch reference, production date or shipment identifier where supplied, purchase-order line, carton numbers and inspected quantity. Photograph unopened packaging and the labels before products are mixed on the inspection table.
- Count total units and reconcile them with the packing list.
- Separate every ordered diameter and face or button configuration.
- Check that item codes and physical products agree.
- Look for mixed colors, body geometries, button counts or markings that may indicate unintended lot mixing.
- Select samples across cartons and positions rather than from one convenient top layer.
If several diameters are included, each variant is its own inspection population unless the agreed plan explicitly groups them. A pass on one size cannot demonstrate conformance of another size.
Step 2: measure the controlled dimensions
Use calibrated instruments appropriate to the tolerance and feature. A digital caliper may be suitable for general outside dimensions, but it is not automatically suitable for every taper or close-tolerance characteristic. The drawing and inspection plan should specify the instrument or gauge when measurement method can affect the result.
| Characteristic | Recommended evidence | Common mistake |
|---|---|---|
| Gauge or head diameter | Measurement at the defined gauge location, with instrument ID and result | Measuring across a random pair of buttons without a defined datum. |
| Overall length and skirt features | Measured values compared with drawing limits | Comparing only with a worn field bit. |
| Taper/socket interface | Approved taper gauge, reference mandrel or fit-check method | Trying to calculate taper from one mouth-diameter reading. |
| Flushing-hole position and size | Visual and dimensional check where specified | Confirming that a hole exists but not that the passage is open. |
| Button layout and protrusion | Count, position and height checks against the drawing | Assuming every bit of the same diameter uses the same layout. |
PerfoMax currently lists H22 taper button bits in 30, 32, 34, 36, 38 and 40 mm inquiry sizes. Those nominal sizes help identify the commercial option, but final inspection must use the approved order-specific tolerance rather than the nominal label alone.
Step 3: confirm taper fit without damaging the product
The taper is a functional contact surface. Inspect it for burrs, dents, corrosion, embedded debris, machining damage and inconsistent finish. Then use the contractually approved gauge or mating reference to check fit.
A useful fit-check record states:
- the gauge or reference-tool identification;
- the required taper designation;
- the cleaning condition of both surfaces;
- the specified seating or contact acceptance method;
- the result and inspector identity.
Do not hammer a production bit onto a rod simply to demonstrate “tightness” unless that destructive or potentially marking test is explicitly approved. A forceful trial can damage the socket, create misleading contact marks or make sample removal unsafe. Use the agreed inspection method and quarantine any unit with a damaged interface.
Step 4: inspect carbide buttons and the bit face
Carbide buttons are central to drilling performance, but a pre-shipment visual inspection cannot verify the entire carbide grade or manufacturing process. It can identify visible nonconformities and confirm that the assembled face matches the approved design.
- Count face and gauge buttons and compare their positions with the drawing.
- Confirm the specified button shape and consistent orientation.
- Look for chipped edges, cracks, impact marks or unusual surface damage.
- Check for visibly uneven seating or protrusion.
- Inspect the steel around each button pocket for cracking, deformation or gaps.
- Use only the agreed non-damaging method to assess looseness; do not pry carbide buttons with an improvised tool.
Button color or a polished appearance is not proof of grade. If carbide grade, chemistry, hardness or retention force is a contractual characteristic, require the corresponding controlled supplier record or agreed test evidence. Do not substitute marketing claims for traceable results.
Step 5: verify flushing passages
A face opening can look correct while the internal passage is restricted by debris, coating or machining residue. Confirm continuity using the approved clean-air, light, probe or flow method. The test must not introduce contaminants or damage the passage.
Record blocked, partially formed, misplaced or heavily burred passages as nonconformities. Their defect class should be agreed before inspection because the operational consequence depends on the bit design and application. Do not “repair” a blocked passage during inspection without authorization; rework can alter geometry and must be re-inspected.
Step 6: inspect the steel body, finish and marking
Rotate each sampled bit under directional light. Inspect the face, gauge, skirt and socket for:
- visible cracks, laps, open seams or abnormal deformation;
- deep dents, impact damage or sharp burrs;
- heavy rust, pitting or coating trapped on functional surfaces;
- machining residue inside the socket or flushing path;
- marking that is missing, unreadable or inconsistent with the ordered variant.
Cosmetic variation should not be confused with a functional defect, but the buyer must define that boundary. A paint shade difference may be minor; paint or scale on a controlled taper contact surface may be major. Use photographs with scale and location references when documenting a nonconformity.
Classify defects before the inspection starts
| Example condition | Possible risk class | Buyer decision required |
|---|---|---|
| Wrong taper or wrong nominal diameter | Critical or major | Define whether any occurrence rejects or contains the lot. |
| Cracked body, missing button or visibly loose button | Critical | Define stop, segregation and supplier investigation rules. |
| Blocked flushing passage | Critical or major | Set the class from application risk and approved design. |
| Dimension outside drawing tolerance | Major | State sampling, recheck and rework disposition. |
| Incorrect marking or mixed variant | Major | Require full segregation and corrected traceability. |
| Minor cosmetic inconsistency away from functional surfaces | Minor | Define an appearance limit or approved sample. |
These are risk examples, not universal classifications. The purchase contract or inspection plan must define the actual classes and acceptance numbers. ISO 2859-1:2026 provides AQL-indexed sampling schemes for lot-by-lot inspection by attributes, but it does not choose the buyer’s AQL, defect definitions or product risks.
For the sampling framework, see AQL Sampling for Rock Drilling Tools.
Sampling plan: what to check 100% and what to sample
Base inspection extent on risk, lot history and contract terms. Many buyers use 100% checks for quantity, variant segregation and obvious critical defects, while dimensional checks may follow an agreed sampling plan. That is a commercial-quality decision, not a universal rule.
The inspection plan should state:
- lot definition and lot size for each variant;
- inspection level and sampling standard, if used;
- AQL or zero-acceptance rule for each defect class;
- which characteristics require 100% inspection;
- random sample-selection method;
- how replacement samples, rework and re-inspection are handled;
- what happens when one critical defect is found.
Keep failed units physically segregated. Do not replace a failed sample with a good unit and continue calculating the original result. The report should preserve the actual inspection outcome and the authorized disposition.
Packaging and release checks
Inspection is incomplete until accepted bits are protected for transport. Verify that bits are clean and dry, functional surfaces have the agreed corrosion protection, and units cannot strike each other inside the package. Mixed sizes need clear physical segregation as well as external identification.
Confirm carton or crate quantity, gross and net weight where required, moisture protection, lifting or handling provisions, shipping marks and packing-list agreement. Photograph each packing layer before closure. If protective oil, caps or wrapping could affect the customer’s receiving process, define the material in advance.
Pre-shipment report checklist
- purchase order, item code and drawing revision;
- supplier lot, production or shipment reference and carton range;
- lot size, sample size and sampling method;
- instrument IDs and calibration status;
- actual dimensional results, not only “OK”;
- taper-fit method and result;
- button, flushing, body, marking and packaging findings;
- defect photographs with unit and location identification;
- accepted, rejected, reworked and held quantities;
- authorized final disposition and inspector sign-off.
Frequently asked questions
Does H22 automatically mean an 11° taper?
No. H22 identifies the hexagonal drill-steel family, not the complete taper specification. Confirm the bit-end taper and approved mating rod separately.
Can a caliper verify the taper angle?
Not reliably from a single mouth-diameter measurement. Use the approved taper gauge, reference mandrel or drawing-defined measurement method.
Should every button bit be dimensionally inspected?
That depends on risk, supplier history and the agreed inspection plan. Define 100% characteristics and sampled characteristics before production; do not decide after seeing the lot.
Is a visual check enough to approve carbide quality?
No. Visual inspection can find chips, cracks and seating problems, but it cannot prove carbide grade or internal integrity. Require traceable records or agreed tests when those properties are contractual.
What is the most important evidence for a claim after delivery?
A report that links the lot, unit, drawing revision, actual measurements, photographs and packing condition. Generic “inspection passed” statements provide weak evidence.
Technical references
- Atlas Copco BBC 16 W product information — OEM reference showing H22 × 108 mm as a pneumatic-rock-drill shank format and the use of tapered button bits.
- Epiroc surface drill bits — OEM discussion of bit-body steel, carbide-button geometry, rock conditions and service-life considerations.
- ISO 2859-1:2026 — official standard page for AQL-indexed lot-by-lot sampling procedures for inspection by attributes.
Send the controlled interface, not only the product name
For an H22 tapered button bit quotation, send the required diameter, taper designation, rod reference, button layout, flushing arrangement, application and acceptance document. PerfoMax can then align the proposed H22 bit route with the same details that will be used at pre-shipment inspection. That closes the gap between RFQ wording, production and final acceptance.