DTH Drill Bit RFQ Checklist: Shank, Diameter, Face, Buttons, and Foot Valve

Direct answer: a reliable DTH drill bit RFQ must identify the exact hammer and shank system first, then state the target hole diameter, bit diameter or tolerance basis, foot-valve/tubeless configuration, rock and drilling conditions, required face/button/flushing configuration if already approved, quantity, and the inspection or documentation expected before shipment. “4-inch DTH bit” or a nominal diameter alone is not enough to control compatibility.

This guide is not a bit-selection article and not a pre-shipment inspection procedure. It is a buyer-to-supplier specification handoff: the minimum information that should be written into an RFQ so the quotation refers to the right interface and the supplier knows which variables are fixed, which may be proposed, and what evidence the buyer expects before bulk production.

1. Why DTH drill bit RFQs are easy to misquote

DTH bits are system components, not isolated cutting heads. Two bits can have a similar nominal diameter but use different shanks, spline geometry, retaining features, shoulders, foot-valve arrangements, face designs, button layouts or flushing passages. That is why an RFQ should start with the hammer interface, not with the visual appearance of the bit.

Current OEM catalogs make this separation clear. Mincon lists shank type, spline/drive details, foot-valve information and bit-size range as separate variables. Epiroc tables likewise map specific shanks to hammer families and then list diameter, product code, button layout, gauge angle, flushing holes and weight. Caterpillar’s DTH selection coding separately identifies bit diameter, shank, face shape, button type, gauge/face buttons, wear protection and flushing holes.

For a buyer, the implication is practical: every RFQ should distinguish between interface data that must match and performance geometry that can be selected or optimized.

2. The information hierarchy: identify first, optimize second

3. Lock the hammer and shank interface before discussing face design

The first technical line of a DTH bit RFQ should identify the hammer and the required shank. If the buyer only knows the old bit, provide all visible markings and clear photographs of the complete shank, splines, retaining area and shoulder. If a controlled drawing exists, attach it.

Do not rely on “3-inch”, “4-inch”, “5-inch” or “6-inch hammer” as the sole interface description. Those size classes are useful for broad discussion, but OEM catalogs show multiple shank systems and bit ranges within the wider DTH market. The exact hammer and shank designation should control the quotation.

A controlled RFQ can use wording such as:

“Bit must match [hammer manufacturer/model] with [exact shank designation]. Supplier to confirm spline, shoulder, retaining feature and valve configuration against attached drawing/photo before quotation.”

This shifts the conversation from “looks compatible” to “interface confirmed.”

4. Separate hole diameter, bit diameter, and tolerance

Buyers often write only the target hole size. That is not always enough. The RFQ should state whether the number refers to:

• the nominal bit diameter ordered;
• the target drilled-hole diameter;
• an existing fleet standard;
• or an allowable dimensional range controlled by a drawing or PO.

Use one unit system consistently and include the converted value only as a reference. Avoid assuming that a rounded inch description uniquely defines a metric bit size.

If dimensional tolerance matters to the project, do not invent a “standard” tolerance in the RFQ. Specify the approved drawing/tolerance or require the supplier to propose the production drawing for buyer approval before manufacturing.

5. Give the rock and drilling conditions before forcing face and button geometry

If the buyer already has a proven configuration, state it. If not, provide the operating conditions and let the supplier propose a configuration for review. Face shape, carbide profile, gauge protection and flushing are performance variables, and OEM product ranges deliberately offer alternatives for different ground and drilling priorities.

A useful RFQ sentence is: “Face, button and flushing configuration may be proposed by supplier for the stated rock/application, but final configuration must be shown on the quotation drawing and approved before production.”

6. Foot valve or tubeless: treat it as a compatibility dependency

Do not write “foot valve: optional” unless the exact hammer system actually supports both configurations. OEM ranges show that foot-valve and tubeless/valveless arrangements vary by hammer and bit family. Boart Longyear, for example, describes tubeless bits for specific QL/QLX systems while noting that some traditional configurations use a foot valve.

Therefore the RFQ should use one of three controlled states:

• Known foot-valve configuration: state it and identify the hammer model.
• Known tubeless/valveless configuration: state it and identify the hammer model.
• Unknown: do not guess; require the supplier to confirm from the exact hammer model, old bit or drawing.

The same principle applies to splines, drive features, retaining components and shoulder geometry. The quotation should reference the compatible shank/configuration, not merely say “fits 4-inch hammer.”

7. Put quality and commercial controls into the RFQ, not after the order

An RFQ is also the right place to define what the buyer expects to receive with the quotation and later with the shipment. If those requirements appear only after price agreement, they can become cost, schedule or acceptance disputes.

Depending on the project, specify:

• quotation drawing or configuration sheet showing the controlled interface and key geometry;
• product marking or batch/lot identification required on each bit or package;
• pilot/sample quantity before bulk production, when applicable;
• inspection scope to be agreed before production;
• documents or material/quality records required by the purchase order;
• packing method, corrosion protection and export marking;
• quantity by configuration when multiple diameters or shanks are ordered;
• delivery destination and commercial terms.

PerfoMax’s current DTH Drill Bit Selection page follows the same principle: final SKU and configuration should be created only after the interface and application are confirmed.

8. Copy-paste DTH drill bit RFQ checklist

Use the following as a practical RFQ template. Delete fields that genuinely do not apply, but do not replace unknown technical fields with guesses.

• Hammer manufacturer / brand: ____________________
• Exact hammer model: ____________________
• Hammer size class (reference only): ____________________
• Required shank designation: ____________________
• Shank drawing / old-bit marking / photos attached: Yes / No
• Foot-valve / tubeless / supplier to confirm: ____________________
• Target hole diameter: ____________________
• Required nominal bit diameter: ____________________
• Diameter tolerance or controlled drawing reference: ____________________
• Hole depth / inclination: ____________________
• Application: quarry / mining / construction / water well / other: ____________________
• Rock type: ____________________
• Rock hardness or UCS if known: ____________________
• Abrasivity: low / medium / high / unknown
• Fracture condition: competent / moderately fractured / highly fractured / unknown
• Wet / dry / groundwater condition: ____________________
• Existing face profile, if fixed: ____________________
• Button shape / size / count, if fixed: ____________________
• Flushing-hole layout, if fixed: ____________________
• Current wear or performance problem, if any: ____________________
• Pilot/sample quantity: ____________________
• Bulk quantity: ____________________
• Required marking / traceability: ____________________
• Required inspection / documentation: ____________________
• Packing / export marking requirement: ____________________
• Destination / Incoterm or commercial requirement: ____________________

9. Bad RFQ vs controlled RFQ

10. Common procurement mistakes to avoid

• Ordering by nominal inch class alone. Hammer size class is not the complete shank specification.
• Using diameter as the only compatibility field. Diameter does not define spline, shoulder, retaining or valve geometry.
• Guessing the foot-valve configuration. Confirm it from the actual hammer system.
• Copying face/button geometry from another site. If the design is not fleet-standardized, provide conditions and require a documented proposal.
• Mixing “hole diameter” and “bit diameter.” State which number is which and what controls acceptance.
• Leaving unknowns blank without saying they are unknown. Mark them “supplier to confirm” and attach the best evidence available.
• Adding inspection requirements only after the PO. Put drawing, marking, evidence and packing expectations into the RFQ.
• Approving a quotation without configuration evidence. For unfamiliar replacement bits, require enough written configuration detail to verify what will be produced.

11. What should be approved before bulk production?

For a new supplier, new shank, new face design or other non-routine replacement, a practical approval package should identify:

1. the exact hammer / shank compatibility basis;
2. nominal diameter and the dimensional drawing or agreed tolerance basis;
3. foot-valve/tubeless configuration;
4. face, carbide button and flushing configuration;
5. marking / traceability method;
6. inspection evidence and packing scope required by the PO;
7. pilot/sample or first-article approval when the buyer’s quality plan requires it.

The goal is not paperwork for its own sake. It is to make the quoted configuration reproducible and reviewable before a bulk lot is manufactured.

Frequently asked questions

Can I request a DTH bit quote by diameter only?

No. Diameter is only one variable. At minimum, identify the hammer and shank system, because interface geometry is independent of nominal bit diameter. Add the application and rock condition when you want the supplier to recommend the cutting geometry.

Is the shank name alone enough?

It is better than a nominal hammer size, but for an unfamiliar supplier or replacement program, also provide the exact hammer model plus a controlled drawing, old-bit marking or clear photos when available. The quotation should confirm the intended interface.

Do all DTH drill bits need a foot valve?

No. Foot-valve and tubeless/valveless arrangements depend on the hammer and bit system. Do not generalize from another hammer family. Confirm the exact configuration against the hammer model or OEM-compatible drawing.

What if I do not know the correct face or button design?

Provide the rock type, relative hardness, abrasivity, fractures, water condition, target hole size/depth and your priority between penetration, straightness and service life. Ask the supplier to propose a configuration and show it on the quotation drawing for approval.

What information matters most before a bulk order?

First lock the compatible hammer/shank and valve arrangement, then the diameter and approved cutting/flushing configuration. After that, define marking, inspection evidence, quantity by configuration and packing. For a project-specific review, request a quote and attach the hammer and current-bit information.

Technical references

1. Mincon — DTH Drill Bits.
2. Epiroc — DTH Product Catalog.
3. Caterpillar — DTH Hammer and Bit Product Brochure.
4. Boart Longyear — DTH Bits.