Plan pneumatic rock-drill spares from failure criticality, verified model compatibility, actual consumption and replenishment lead time—not from a generic “one kit per drill” rule. For a YT28, Y19A or mixed pneumatic-drill fleet, identify the exact drill and revision first, separate field-replaceable items from workshop-only parts, calculate a reorder point for proven consumption items, and keep a controlled standby strategy for failures that cannot be repaired safely at the worksite.
This guide is for mines, quarries, contractors and distributors preparing spare stock for remote or import-dependent operations. It does not declare that a part fits every drill in a model family, prescribe universal replacement intervals or authorize field repair. Final part numbers, dimensions, materials, repair competence and acceptance limits must follow the supplied parts list, drawing and service instructions for the exact drill.
Why a “spare-parts kit” is not enough
Two kits sold under the same model name can contain different revisions, quantities or quality levels. A low-cost kit may overstock seals while omitting the part that stops a remote crew. A large kit can also create false confidence if the part numbers, handed components or mating interfaces are not controlled.
The procurement job is therefore not “buy more parts.” It is to decide which failure must be recoverable at site, which repair belongs in a workshop, what evidence proves compatibility, and when stock must be reordered before lead time creates downtime.
Freeze the fleet identity before counting stock
| Input to record | Why it changes the spare plan | Evidence to keep |
|---|---|---|
| Model and nameplate identity | Similar model names do not prove internal interchangeability | Nameplate photo and serial or batch record |
| Parts-list or drawing revision | Part numbers and assemblies can change across production revisions | Controlled manual, exploded view or supplier drawing |
| Shank and steel interface | Chuck, bushing, retainer and striking interfaces must match the drill steel | Interface designation and measured/approved reference |
| Air-leg configuration | Air-leg seals, valves and connectors belong to the leg configuration, not only the drill body | Leg model, suffix and connection photos |
| Fleet quantity and utilization | Ten standby drills and ten continuously operating drills create different demand | Active units, standby units and operating hours |
| Site repair capability | A stocked internal part has no downtime value if it cannot be fitted and tested safely | Approved job scope, tooling and competent-person list |
| Replenishment lead time | International freight, customs and remote transport expand exposure | Recent order-to-site history, not only supplier dispatch time |
| Failure and issue history | Actual repeat consumption should replace assumptions | Work orders, stores issues and removed-part evidence |
Keep YT28, Y19A and other model stock physically and digitally separated until equivalence is proven. For model-specific maintenance boundaries, use the Y19A maintenance checklist and the YT28 troubleshooting guide.
Use three inventory tiers
Tier 1: site-service parts
These are items that the approved site procedure allows a competent technician to inspect, replace and verify with available tools. Depending on the exact drill, examples may include specified seals, springs, fasteners, strainers, connectors or external controls. Inclusion in a parts diagram does not automatically make an item field-serviceable.
Tier 2: workshop repair parts
These require controlled disassembly, inspection, fitting, measurement or a press. Rotation components, chuck-related parts, valve-group components and internal wear parts often fall here, but the exact boundary is model-specific. Stock them only where the workshop can complete the repair and the required post-repair test.
Tier 3: recovery assemblies or standby units
For a remote crew, a complete verified assembly or standby drill can restore production faster than opening a damaged drill at the face. This tier is justified by production consequence, repair duration and transport lead time—not by the purchase price alone.
Criticality matrix for the initial stock decision
| Question | Low priority | Medium priority | High priority |
|---|---|---|---|
| Does failure stop drilling? | Cosmetic or non-operating item | Output reduces but controlled work can continue | Drill or air leg cannot be released |
| Can the failure damage other parts? | No credible propagation | Extended use increases wear | Continued use can damage the piston, shank, housing or connection |
| How predictable is consumption? | No recorded use | Occasional use with incomplete evidence | Repeated issues across work orders or stores records |
| How long is replenishment? | Local and verified | Regional or variable | Imported, remote or customs-dependent |
| Can the site fit and test it? | No; external overhaul only | Workshop capability exists with limits | Approved field procedure, tooling and release test exist |
| Is compatibility controlled? | Part identity uncertain | Model match only | Part number, revision and mating interface verified |
A part becomes a priority spare when its failure consequence, observed demand and lead-time exposure are high and the site can use it correctly. An unidentified “common part” should be quarantined rather than counted as available stock.
Build the first bill of spares by failure function
Start with the functions that can stop or degrade the drill, then map each function to the exact illustrated parts list. Do not copy another fleet’s part numbers.
- Air admission and control: inlet, throttle and valve-related items specified for the model.
- Percussion: internal striking and valve components only where workshop replacement is authorized.
- Rotation: verified pawls, springs, ratchet or spline components where applicable. The no-rotation guide helps separate external binding from internal rotation faults before parts are issued.
- Drill-steel guidance and retention: the correct bushing, chuck, retainer and associated parts. Use the chuck-bushing wear guide before assuming that play requires one specific component.
- Fastening and housing alignment: exact side rods, nuts, washers and related hardware where the model procedure permits replacement.
- Flushing: model-controlled water or air-flushing components, seals and connectors.
- Air-leg support: seals, valves, connectors and mechanical items matched to the leg model and suffix.
- External air system: approved hose-end, coupling, restraint, line-oiler and strainer service items kept separate from internal drill parts.
When one symptom can have several causes, stock planning must follow diagnosis. Issuing a rotation kit for a bound bit or an internal valve for a restricted hose consumes inventory without resolving the failure.
Calculate a reorder point from real consumption
For a repeat-use item, use a simple site-controlled formula:
Reorder point = average daily issue × replenishment lead time + safety stock.
Use the same time basis for both demand and lead time. Count only verified issues to the relevant fleet, and separate planned rebuild consumption from unplanned failures.
Worked example
A site issued 12 verified rotation service sets over the last 120 calendar days to the same controlled fleet. Average demand is 12 ÷ 120 = 0.10 set per day. The measured order-to-site lead time is 45 days, so expected lead-time demand is 0.10 × 45 = 4.5 sets. The site rounds this to 5 and approves safety stock of 3 sets for demand and freight variability. The reorder point is therefore 8 sets.
This example demonstrates the method, not a recommended quantity for every mine. If demand is intermittent, failure consequence is high or history is short, review the result with maintenance and procurement rather than creating false precision. A standby drill can be a better control than deep stock of workshop-only internals.
Set four stock decisions
| Decision | Use when | Required action |
|---|---|---|
| STOCK | Compatibility is proven, demand or consequence is credible, and the site can fit/test the part | Set minimum, maximum, reorder point and storage controls |
| ORDER ON FAILURE | Lead time is acceptable and downtime consequence is low | Keep the verified supplier and part record current |
| STANDBY ASSEMBLY / DRILL | Repair is slow, workshop-only or production-critical | Preserve, inspect and periodically function-check the standby asset |
| DO NOT STOCK / QUARANTINE | Identity, revision, quality evidence or repair authority is missing | Resolve evidence before treating the item as available inventory |
Compatibility gate before purchase
- Match the drill and air-leg model exactly, including suffix or revision where used.
- Confirm the supplier part number against the current illustrated list or drawing.
- Check the mating component, orientation, thread, fit and material/heat-treatment requirement where specified.
- Request photos and dimensions only as supporting evidence; visual similarity is not interchangeability proof.
- Define whether the quoted item is an individual part, matched pair, service set or complete assembly.
- Record approved alternates separately, with the technical basis and approving person.
- For safety- or fatigue-critical items, require the specified traceability and inspection evidence.
Do not transfer a family-level wear limit from another brand or model to a PerfoMax drill. The quotation and supplied technical file must control the final compatibility decision.
Receiving and storage checks
- Reconcile part number, revision, description, quantity and purchase order.
- Separate model-specific bins; do not combine visually similar springs, seals or fasteners.
- Protect precision surfaces, threads and elastomers from contamination, sunlight, heat and incompatible preservatives.
- Keep labels with the part and retain supplier/batch evidence where required.
- Inspect packaging damage, corrosion, deformation and contamination before placing stock into service.
- Use first-expire or first-in controls where shelf life applies, based on supplier data.
- Quarantine returned or opened parts until their identity and condition are re-established.
Close the loop after every issue
A useful stock plan changes with field evidence. For each issue, record the drill identity, operating hours if available, symptom, diagnosed cause, part fitted, removed-part condition, repair location and release result. Review repeat failures by drill, shift, site, supplier lot and technician. High consumption may signal incorrect setup, contamination, misalignment or a wrong part—not a need to raise the reorder point automatically.
spare-parts planning record
Site / fleet: Drill model and revision: Air-leg model / suffix: Active units / standby units: Operating pattern: Parts-list or drawing revision: Approved field-service scope: Approved workshop scope: Part description / part number: Mating component: Failure consequence: Issues in review period: Average demand: Measured order-to-site lead time: Safety stock basis: Reorder point: Minimum / maximum: Storage or shelf-life control: Approved supplier / alternate: Receiving evidence required: Last review / next review: Approver:
RFQ block for pneumatic rock-drill spares
Send the supplier the drill and air-leg nameplate photos, serial or batch reference, current parts-list revision, required part numbers, quantities, mating-component details and photos of the removed parts. State whether parts are for routine field service, workshop repair or a standby assembly. Request confirmation of compatibility, scope of supply, revision, material or treatment evidence where specified, packaging, shelf life, lead time and post-repair test requirements.
For fleet matching, review the PerfoMax rock-drill range, including the active YT28 air-leg drill and Y19A hand-held drill. For a model-controlled spare quotation, send the identification package to PerfoMax.
Frequently asked questions
What pneumatic rock-drill parts should every site stock?
There is no universal list. Start with exact model identity, approved repair scope, repeat consumption, failure consequence and lead time. A remote site may justify a standby drill even when an urban workshop does not.
Can YT28 parts from different suppliers be mixed?
Only when the current part number, revision, mating interface and technical requirements are verified. A shared model label or similar appearance is not sufficient.
Should we stock complete repair kits or individual parts?
Use matched service sets where the approved procedure requires parts to be replaced together. Stock individual parts only when the procedure, compatibility evidence and failure history support that approach.
How often should reorder points be reviewed?
Review after a lead-time change, fleet-size change, repeat failure, supplier revision or enough new consumption history to alter the demand estimate. Remote operations should also review before seasonal access constraints.
Does a spare part solve repeated failures?
No. Repeated consumption is a diagnostic signal. Preserve removed-part evidence and check supply quality, lubrication, alignment, operation, repair method and compatibility before increasing stock.
Safety boundary
Isolate and depressurize the drill and air leg before inspection or parts work. Internal service, pressing, grinding, heat treatment and fatigue-critical repair require the approved procedure, tooling and competent personnel. Apply local work-equipment rules and recognized guidance such as HSE PUWER. After repair, complete the model-specific inspection and controlled function test before release.