Direct answer: the H22 drill-steel shank is the machine-side end of the rod. Its striking face receives piston impact, the hexagonal section engages the rock drill's chuck or chuck bushing for guidance and rotation, the forged collar controls the rod's axial position in the front end, and the hollow bore carries flushing medium toward the bit. These features work as one interface; none should be specified from the word “H22” alone.
This guide explains the terminology and load path for buyers, quarry teams, distributors and technical procurement staff. It does not define a universal inspection tolerance. Final dimensions, datums, clearances and service limits must come from the exact rock-drill manual, the applicable standard and the approved supplier drawing.
H22 shank anatomy at a glance
In purchasing language, “H22” normally identifies the nominal 22 mm hexagonal drill-steel family. It is a starting point for interface control, not a complete rod specification. A finished tapered rod also has a rod body, a central flushing passage and a separate bit-end taper. Integral steel replaces the detachable tapered bit with a forged cutting end, but the machine-side shank still needs to match the drill.
| Feature | Where it is | Primary job | What a buyer should control |
|---|---|---|---|
| Striking end | Flat machine-side end contacted by the piston | Receives repeated axial impact | End form, condition and specified shank family |
| Hex shank surfaces | Between the striking end/collar region and the rod body | Engage the chuck arrangement for rotational drive and lateral guidance | Nominal size, length, form and drawing tolerances |
| Forged collar or shoulder | Raised feature near the machine-side end | Locates the rod axially and establishes the intended striking position | Collar diameter, thickness, position and transition geometry |
| Transition radii | Where the collar blends into the shank/body | Carry changing stress through the change in section | No drawing ambiguity, sharp damage or uncontrolled rework |
| Central bore | Through the hollow drill steel | Conducts air or water toward the bit for cuttings removal | Bore continuity and the drill-specific flushing entry arrangement |
| Bit-end connection | Opposite end of a tapered rod | Seats the detachable bit | Taper angle and bit socket as a separate interface |
The terminology matters because the same complaint can point to different interfaces. A mushroomed striking end is not the same problem as a loose tapered bit. A worn chuck bushing is not a rod-length issue. A blocked bore is not proof that the shank size is wrong.
How impact, rotation, guidance and flushing enter the drill steel
Impact enters through the striking face
The rock-drill piston hits the striking end and sends a compressive stress wave along the steel toward the bit. The striking face therefore belongs to the machine-side impact interface. Its position relative to the collar and chuck is controlled geometry, not a cosmetic detail. If the rod sits too far in or too far out, the intended contact relationship can change.
Do not infer an acceptable end-face condition from appearance alone. The equipment maker's service instructions and the supplier's controlled drawing should govern. For field-failure diagnosis, use the separate H22 shank mushrooming guide.
Rotation is transmitted through the engaged hex surfaces
The non-circular shank gives the chuck arrangement surfaces that can transmit rotation without relying on friction alone. Those same surfaces help guide the steel in the front end. The exact contact pattern, running clearance and allowable wear are model-specific. “It slides into the chuck” is therefore not enough to prove correct fit.
This is why the drill steel and chuck bushing are best treated as a pair. ISO 723 covers forged collared shanks and their corresponding chuck bushings for hollow hexagonal rock-drill steel. That scope is a useful reminder: a nominal steel size is only meaningful when the matching machine-side geometry is also controlled.
The collar establishes axial position
The collar is the raised forged feature that provides a locating shoulder. In practical terms, it helps place the striking end where the drill design expects it and prevents uncontrolled travel through the front end. Collar position and thickness can affect insertion depth even when two rods share the same nominal hex size.
A collar should not be treated as a convenient handle, a wear mark or an optional swelling in the steel. It is an interface feature. Photos are helpful for identification, but purchase release should use a drawing or an exact approved part reference.
Flushing follows a separate internal path
Hollow drill steel carries air or water through its central bore toward the bit, where the medium helps move cuttings away from the hole bottom. The route by which flushing enters the rod depends on the rock drill and front-head design. Some systems introduce flushing around or through machine-side passages before it reaches the bore; the exact ports, seals and clearances are not universal.
For that reason, a clear bore does not prove that the complete flushing system is compatible. Confirm the drill's flushing method, the rod bore and the bit outlet arrangement as one continuous path. ISO 1718 addresses basic dimensions for drill rods and tapered connections, while the equipment manual remains the controlling source for the machine-side flushing arrangement.
What “H22 × 108” does—and does not—tell you
“H22 × 108” is commonly used as a machine-side shank family: H22 for the nominal hexagonal steel size and 108 mm for the associated shank-length designation. However, buyers should not assume the precise measurement datums, tolerances or collar position from the label. Ask where the 108 mm is measured on the approved drawing.
Atlas Copco, for example, lists an H22 chuck and an available Hex 22 × 108 mm shank for its BBC 34-DSI pneumatic rock drill. That confirms that the designation is used for a real machine interface; it does not make every H22 × 108 rod interchangeable across all drills, rebuilds or front-head variants.
| The description can identify | It does not automatically specify |
|---|---|
| A nominal machine-side hex/shank family | Exact fit to every drill that accepts H22 steel |
| A nominal shank-length designation | The drawing datum used to measure that length |
| The starting point for chuck and bushing verification | Bit-end taper angle, rod length or bit diameter |
| A term for RFQ screening | Approved substitution without model and drawing review |
For a complete replacement workflow, see the published H22 × 108 drill-steel compatibility guide. It treats the drill, shank, rod, taper and bit as separate checkpoints.
Machine-side shank versus bit-side taper
The two ends of a tapered drill rod solve different connection problems. The shank fits the rock drill. The taper fits the detachable bit. Mixing the terms can create a rod that fits the machine but rejects the existing bit, or a bit that fits the rod while the rod is wrong for the drill.
| Question | Machine-side shank | Bit-side taper |
|---|---|---|
| What does it connect? | Rock drill, chuck and chuck bushing | Rod and detachable tapered bit |
| Typical terms | H22, H22 × 108, collar, striking end | 7°, 11°, 12°, socket, taper seat |
| Primary loads | Piston impact, rotational drive and guidance | Impact/rotation transfer into the bit and seating retention |
| Controlling evidence | Rock-drill manual and shank drawing | Rod/bit drawing and confirmed taper system |
Sandvik's current tapered-bit range, for example, lists 7°, 11° and 12° options. That illustrates why the taper must be stated independently from H22 × 108.
Terminology mistakes that cause wrong orders
- Calling the whole rod “the shank.” The shank is the machine-side interface, not the complete working length.
- Using H22 as a complete part number. It does not define the collar, shank-length datum, taper, rod length, bore or bit.
- Assuming 108 mm is self-explanatory. A drawing should show the measurement start and end points.
- Calling the collar a retainer. Retention hardware belongs to the drill; the forged collar is a feature on the steel. Use the machine manual's exact names.
- Using a worn rod as the master sample. End upset, collar wear, scoring and hex wear can corrupt measurements.
- Assuming the bore fixes the shank fit. Flushing compatibility and mechanical engagement are related system checks, but they are not the same dimension.
Drawing and RFQ checklist for an H22 shank
When the installed tooling record is incomplete, send enough evidence for the supplier to identify both interfaces without guessing:
- Rock-drill manufacturer, exact model, suffix/variant and serial range if relevant.
- Machine nameplate photo and the applicable tooling or operating-manual page.
- Required shank designation, such as H22 × 108, marked as “to be confirmed” if uncertain.
- Dimensioned shank drawing showing the striking face, hex length, collar position, collar size, transition radii and bore.
- Clear photographs of an unused approved rod, or the least-worn confirmed sample, with a scale reference.
- Rod type: tapered detachable-bit rod, integral steel or another configuration.
- Overall/effective rod length and the datum used to define it.
- Bit-end taper angle, bit type and target hole diameter stated separately.
- Air or water flushing method and any drill-specific entry details.
- Quantity, marking, packing, inspection records and acceptance criteria required with the order.
If a drawing and an old field sample disagree, do not average the dimensions. Stop the release and reconcile the drawing revision, machine configuration and sample history.
FAQ
What does H22 mean on rock-drill steel?
It identifies the nominal 22 mm hexagonal drill-steel family used at the machine-side interface. Exact tolerances and finished shank geometry still require a standard, machine manual or approved drawing.
Is the 108 mm in H22 × 108 measured from the striking face to the collar?
Do not assume a universal datum. The 108 mm is a nominal shank-length designation, but the controlling drawing should show exactly where the measurement starts and ends and how the collar is referenced.
What does the collar on a tapered drill rod do?
The forged collar acts as a locating shoulder that helps establish the rod's intended axial position in the rock-drill front end. Its dimensions and position are therefore part of the machine interface.
Does the hex section carry impact or only rotation?
Impact enters axially through the striking face and travels along the steel. The engaged hex surfaces primarily provide rotational drive and guidance, while the full shank geometry supports the intended load path. Exact contact and clearance conditions are drill-specific.
Can I copy an H22 shank from a used rod?
A used rod can support identification, but it should not be the only dimensional authority. Wear, mushrooming, scoring or collar damage can change measurable features. Prefer an approved drawing or an unused, traceable sample.
Technical sources
- ISO 723:1991 — Rock drilling equipment — Forged collared shanks and corresponding chuck bushings for hollow hexagonal drill steels.
- ISO 1718:1991 — Rock drilling equipment — Drill rods with tapered connection for percussive drilling.
- Atlas Copco — BBC 34-DSI pneumatic rock drill.
- Sandvik — Tapered bits.
Specify the shank before releasing the rod order
PerfoMax supports H22 tapered drilling-tool inquiries for mines, quarries, contractors and distributors. Start with the exact rock-drill model and a controlled shank drawing, then confirm the rod length, bit-end taper, flushing arrangement and hole requirement as separate fields.
Browse drill rods or send the machine and tooling details for an RFQ review. The written quotation and approved drawing should control the final configuration.