Quick answer: for the current PerfoMax reference configurations, the YT28 is the more conservative starting point when your drilling pattern stays within 34–42 mm and plant air is a constraint, while the YT29A extends the reference hole range to 34–45 mm and carries a higher reference air demand. Both current product pages use an H22 × 108 mm shank reference, but that does not make every rod, bit, taper, air leg, hose, oiler, or supplier revision automatically interchangeable.
The selection problem is therefore not “Which model is stronger?” It is: Which quoted configuration matches the hole diameter, available pressure and airflow at the drill, drill-string interface, and approved air-leg setup? This guide is written for mines, tunneling contractors, quarry operators, distributors, and industrial buyers comparing YT28 and YT29A before an RFQ or replacement order.
Important: the figures below are reference values currently published on PerfoMax product pages. Final procurement should be controlled by the supplier datasheet, test pressure, approved air-leg combination, and exact quotation.
1. YT28 vs YT29A: Quick Comparison
| Selection point | YT28 current reference | YT29A current reference | Buyer implication |
|---|---|---|---|
| Reference hole diameter | 34–42 mm | 34–45 mm | YT29A covers a wider upper end; do not size the machine only from the maximum diameter. |
| Weight | 26 kg | 26.5 kg | Handling difference is small; system match matters more than 0.5 kg. |
| Overall length | 661 mm | 659 mm | Very similar envelope; verify the quoted drawing for replacement work. |
| Cylinder × stroke | 80 × 60 mm | 82 × 60 mm | YT29A uses a larger reference cylinder diameter, but field output still depends on pressure, bit, feed, and rock. |
| Impact frequency | ≥37 Hz | ≥39 Hz | Only compare frequency values when test conditions and configuration are equivalent. |
| Air consumption | ≤81 L/s | ≤88 L/s | YT29A asks more from the compressed-air system in the current reference data. |
| Reference shank | H22 × 108 mm | H22 × 108 mm | Same shank class does not prove complete rod/bit/taper compatibility. |
For current PerfoMax product details, see the YT28 air-leg rock drill and YT29A air-leg rock drill pages.
2. First Rule: Never Compare Catalog Numbers Without the Test Condition
One of the easiest procurement mistakes is putting two specification sheets side by side and assuming every airflow, impact-frequency or energy figure was measured under the same pressure. Published values can differ because the pressure point, test setup, tool revision and reporting basis differ. The useful rule is that model name alone is not a complete test condition.
Use the current PerfoMax product pages only as reference configurations for preliminary comparison. Before purchase, require the quotation to attach the controlled data sheet for the exact offered drill and state the pressure and test conditions behind each performance value.
Before deciding that one machine consumes less air or drills faster, confirm:
- test or working pressure used for the published figure;
- where pressure is measured—compressor outlet, manifold, or at the drill;
- hose length and internal diameter;
- oiler, valves, fittings, and pressure losses;
- bit diameter, rock condition, and drill-string configuration;
- air-leg feed condition and water injection setup.
Do not convert a catalog L/s value directly into a compressor purchase specification unless the supplier has confirmed the operating pressure, simultaneous loads, distribution losses, and required reserve margin.
3. Hole Diameter: 42 mm vs 45 mm Is a Boundary, Not the Whole Decision
The current PerfoMax reference range is 34–42 mm for YT28 and 34–45 mm for YT29A. That makes the first screening decision straightforward:
- If all planned holes are 34–42 mm: both models may be candidates, so air supply, rock, drilling rate, existing spares, and air-leg configuration become the next filters.
- If the pattern requires 43–45 mm holes: the current YT29A reference range covers that diameter, while the current YT28 reference range does not.
- If the requested diameter sits outside both published ranges: do not stretch the model by assumption; confirm another drill, bit, or drilling method.
Diameter also changes the load on the whole system. A larger bit changes rock contact, cuttings volume, flushing demand, feed behavior, and the energy required to maintain penetration. Therefore, “YT29A reaches 45 mm” should be treated as a compatibility boundary to verify—not a promise that it will always drill a 45 mm hole efficiently under any compressor or rock condition.
4. Air Supply: Why the YT29A Can Be the Wrong Upgrade on an Air-Limited Site
In the current PerfoMax reference data, YT28 air consumption is ≤81 L/s and YT29A is ≤88 L/s. The difference looks modest on paper, but a field system can be sensitive to pressure loss, especially when several pneumatic tools share the same header.
If pressure at the drill falls under load, the buyer may experience reduced impact performance, slower penetration, unstable drilling, or a machine that appears weaker than its catalog. In that situation, buying the nominally higher-output model does not automatically solve the problem. It can simply place more demand on the same restricted air network.
Before changing from YT28 to YT29A, record:
- compressor rated output and rated pressure;
- measured pressure at the tool while drilling, not only static pressure;
- main-line and branch-line sizes;
- hose length and inside diameter to each drill;
- number of tools operating simultaneously;
- condition of couplings, valves, filters, and lubricators;
- whether water injection creates any additional operating constraint.
The right compressor decision should be made from the complete pneumatic system, not from multiplying one catalog number by the number of drills.
5. Does the YT29A Automatically Drill Faster Than the YT28?
No. The YT29A current reference configuration has a slightly higher impact-frequency figure and a larger reference cylinder diameter, but that does not guarantee a higher field penetration rate in every hole.
Actual drilling rate is affected by rock strength and fracturing, bit type and sharpness, bit diameter, pressure at the drill, air-leg feed, flushing/water condition, rod condition, collaring quality, and operator technique. A correctly supplied YT28 on a 36–40 mm pattern can outperform a poorly supplied YT29A that is starved for air or matched to the wrong bit and feed condition.
For procurement, compare cost per acceptable drilled meter under the same site condition, not only nominal frequency or a supplier’s “more powerful” description.
6. H22 × 108 mm: Same Shank Class Does Not Mean Full Interchangeability
Both current PerfoMax YT28 and YT29A pages identify H22 × 108 mm as the reference shank. That is useful because it narrows the drill-string family, but it is not enough to approve a replacement order.
H22 describes the hexagonal steel size, while the complete drilling connection still depends on the shank end, taper angle, rod length, bit socket, and supplier tolerances. PerfoMax currently lists an H22 × 108 mm rod with an 11° connection option; that product is an example of why the taper must be specified rather than inferred from “H22” alone.
When reusing an existing rod and bit inventory, send the supplier:
- rock-drill model and nameplate photo;
- rod shank size and shank-end dimensions;
- taper angle or verified bit/rod part number;
- bit diameter and bit style;
- rod length;
- photos of the current drill, rod end, and bit socket if drawings are unavailable.
7. Air-Leg Matching Is Part of the Drill Configuration
An air-leg rock drill should not be purchased as an isolated body. The feed leg affects support, feed force, working angle, hose routing, and operator control.
The current PerfoMax YT28 page identifies FT160BC/FT160BD as common pairings. For YT29A, the exact approved air-leg suffix should be confirmed in the quotation instead of being inferred from another supplier’s compatibility table. PerfoMax also lists the FT160-series pneumatic air legs as model-specific equipment where the suffix matters.
For a replacement purchase, do not write only “FT160.” Confirm the exact suffix, mounting interface, working length, hose and control arrangement, and whether the quotation includes the leg, oiler, water accessories, and required connectors.
8. Practical Selection Matrix
| Site condition | Best starting point | What still needs confirmation |
|---|---|---|
| 34–42 mm holes, existing air system has limited spare capacity | YT28 | Pressure at drill, bit/rod match, air-leg suffix, actual duty cycle. |
| 43–45 mm holes are required | YT29A | Air capacity, bit diameter, rock condition, drill-string and leg configuration. |
| 34–42 mm holes, buyer wants higher nominal reference frequency | Compare both | Do not decide from Hz alone; compare equal test conditions and field air supply. |
| Replacing an existing YT28 with YT29A but keeping H22 tooling | Engineering confirmation | H22 × 108 is only one interface dimension; verify taper, rod, bit, shank and leg. |
| Mixed-brand fleet with unknown datasheet revisions | Engineering confirmation | Use nameplates, drawings, measured interfaces and supplier-controlled data. |
| Compressor pressure drops when multiple drills run | Fix/validate air system first | Loaded pressure, hose loss, branch capacity, simultaneous tool demand. |
8A. Controlled Fleet Trial Before Replacing YT28 with YT29A
A catalog comparison can narrow the choice, but it cannot approve a fleet change. Before replacing a working YT28 population with YT29A—or adding YT29A to a mixed fleet—run a controlled site trial that preserves the identity of each complete configuration. The decision should be based on required holes and repeatable field evidence, not an assumed percentage improvement.
| Approval gate | Evidence required | Hold condition |
|---|---|---|
| 1. Model identity | Nameplate, supplier, revision, controlled product sheet and parts information for both the baseline YT28 and candidate YT29A. | The drill is identified only by a painted model name, or figures from different supplier revisions are being combined. |
| 2. Application boundary | Required hole-diameter range, typical depth, drilling direction, rock variability, shift pattern and reason for considering the change. | The site has not defined whether it needs the YT29A reference range, or the problem is actually a worn bit, blocked flushing path or unstable hole. |
| 3. Air-system capacity | Compressor output under the site condition, simultaneous drill count, branch layout and dynamic pressure measured near each drill while working. | The candidate can be tested only by raising pressure beyond a component rating, or other tools lose pressure when it starts. |
| 4. Hose, coupling and oiler path | Hose ID and length, smallest coupling bore, connection profile, retention, lubricator model and verified oil delivery for each approved configuration. | An undersized or unidentified component would make the comparison a hose-system test rather than a drill comparison. |
| 5. Air-leg and control match | Exact leg model and suffix, mounting interface, working geometry, controls and supplier-approved pairing. | “FT160” is the only information available, the suffix is unknown, or the candidate must be forced onto an unverified leg. |
| 6. Drill-steel and bit system | Verified H22 × 108 shank, rod length and straightness, taper, bit socket, diameter, wear condition and flushing passage. | The same-looking steel has not been dimensionally or documentarily matched, or the baseline and candidate use materially different consumable condition. |
| 7. Water and safety controls | Approved water setup, isolation method, retained steel, secure connections and the site controls required for the trial. | Leakage, water backflow, insecure retention, unpredictable movement or any unresolved stop-work condition is present. |
| 8. Repeatable trial result | Comparable holes in similar ground with cycle time, loaded pressure, interruptions, bit/rod condition and operator observations recorded. | Only one unrepeatable hole was drilled, the ground changed materially, or several system variables changed together. |
Run the comparison without hiding a configuration mismatch
- Define the success criterion before drilling: required hole diameter and depth, acceptable cycle outcome, air-system stability, consumable condition and any site-specific limit.
- Prepare the current YT28 as the baseline using its verified hose, leg, oiler, water path and drill string. Record the as-found condition before replacing anything.
- Prepare the YT29A as its own approved configuration. Do not force the candidate to share an air leg, hose or accessory merely to make the trial look like a one-part swap.
- Hold rock condition, drilling direction, operator method, bit/rod condition and measurement points as constant as the site can reasonably achieve. Record unavoidable differences.
- Measure dynamic pressure near the operating drill and note the effect on other simultaneous users. If airflow measurement is available, record its reference basis and operating condition.
- Repeat enough comparable holes to distinguish a stable result from collaring variation, a seam or one unusually difficult hole. The site procedure—not this guide—sets the required sample.
- After the trial, isolate and depressurize the equipment, then inspect the shank, retainer, chuck area, rod, bit, hose connections and leg for new abnormal marks, heat, leakage or loosening.
Fleet decision gate
| Status | Use when | Action |
|---|---|---|
| APPROVE YT29A | The wider reference range or measured site result is required, all interfaces pass and the air system remains stable. | Release the documented configuration and attach the approved parts, leg, hose, oiler and consumable list to purchasing. |
| RETAIN YT28 | The existing hole pattern is met and the candidate adds no verified operational or commercial advantage. | Keep YT28 as the fleet standard and correct any separate air, tooling or maintenance issue. |
| CONDITIONAL EXTENDED TRIAL | The complete configuration is safe and compatible, but ground variability or limited observations prevent a fleet decision. | Extend the controlled trial with predefined evidence requirements; do not treat the candidate as generally approved. |
| HOLD OR REJECT CONFIGURATION | Identity, air capacity, leg pairing, drill-steel compatibility, safety control or repeatability is unresolved. | Segregate the candidate configuration and resolve the failed gate before another production test. |
Copy-ready YT28–YT29A trial record
- Site, heading or bench; date; operator; approver; trial purpose.
- Baseline YT28 and candidate YT29A supplier, serial or batch reference, nameplate and document revision.
- Hole diameter, target depth, direction and comparable ground description.
- Compressor and simultaneous users; hose ID/length; coupling bore/profile; loaded pressure measurement point and gauge ID.
- Air-leg model and suffix; oiler; water setup; H22 shank, rod, taper, bit diameter and wear condition.
- Per-hole cycle observations, interruptions and any airflow result with its reference condition.
- Post-trial marks, heat, leakage, loosening and consumable inspection.
- Decision: APPROVE YT29A, RETAIN YT28, CONDITIONAL EXTENDED TRIAL, or HOLD/REJECT; open actions and owner.
9. Six Procurement Mistakes That Create Avoidable Downtime
- Comparing airflow figures from different pressures. A lower L/s number is meaningless if the test condition is different.
- Assuming YT29A is always the better drill. A higher-capacity model can be a worse system match when air is constrained or the hole pattern does not need the wider diameter range.
- Ordering by model name only. Manufacturer, revision, pressure basis, and interfaces must be controlled.
- Treating H22 × 108 as complete drill-string compatibility. Confirm taper angle, bit socket, rod geometry, and actual part numbers.
- Ignoring the air-leg suffix. FT160 is a family name; approved pairings and geometry must be verified.
- Leaving hoses, oiler, and water setup out of the RFQ. The drill body can be correct while the installed system is still wrong.
10. RFQ Checklist: What to Send Before Ordering YT28 or YT29A
A useful RFQ should contain enough information for the supplier to reject a bad match before shipment. Send:
- required hole diameter range and typical hole depth;
- rock type, hardness description, and whether the formation is massive, fractured, or variable;
- number of drills that operate at the same time;
- compressor model, rated output, rated pressure, and measured loaded pressure at the drill if available;
- existing hose ID and approximate hose length;
- required drill model: YT28, YT29A, or supplier to recommend;
- existing air-leg model and exact suffix;
- rod shank, taper angle, rod length, and bit diameter;
- photos of nameplates and interfaces for replacement orders;
- whether the quote must include air leg, oiler, hoses, water accessories, spare parts, and tools;
- required inspection, packing, documentation, and destination details.
If your application is still open, start with the current PerfoMax Rock Drills collection and provide the operating data above so the quoted configuration can be checked as a complete system.
11. FAQs
What is the main difference between YT28 and YT29A?
In the current PerfoMax reference configurations, YT28 covers 34–42 mm holes with ≤81 L/s reference air consumption, while YT29A covers 34–45 mm with ≤88 L/s and a slightly higher reference impact frequency. The practical difference is therefore a combination of hole range and pneumatic-system demand, not simply smaller versus stronger.
Can YT28 and YT29A use the same H22 × 108 drill rods?
Both current product pages specify an H22 × 108 reference shank, so they belong to the same general shank class. However, rod and bit interchangeability still requires confirmation of taper angle, shank-end geometry, bit socket, dimensions, tolerances, and supplier revision.
Why do different YT28 or YT29A catalogs show different air-consumption figures?
Published specifications can use different test pressures and configurations. A public 0.5 MPa comparison, for example, reports different airflow and frequency figures from other tables that state a broader 0.4–0.63 MPa range. Always compare values at equivalent test conditions.
Should I choose YT29A if I want faster drilling?
Not automatically. Field penetration depends on delivered pressure, bit condition and diameter, rock, feed, flushing, rod condition, and operator setup. A well-matched YT28 can be the better production choice on a 34–42 mm pattern with limited air capacity.
What should I measure if the drill loses power when several machines run?
Measure dynamic pressure at the drill while the tools are operating, then check compressor capacity, distribution line size, branch restrictions, hose ID and length, fittings, filters, and lubricators. Static compressor pressure by itself does not show what the drill receives under load.
Technical and Safety Boundaries
- ISO 11148-5 defines general safety requirements for handheld non-electric rotary percussive drills.
- UK HSE HSG39 supports compressed-air isolation, inspection and safe-use boundaries.
- OSHA 29 CFR 1926.302 provides jurisdiction-specific requirements for pneumatic tools, hoses and connections.
These sources define safety boundaries, not YT28 or YT29A performance. Hole ranges, air demand and interface claims in this guide are tied to the current PerfoMax reference pages; the final quotation and supplier-controlled data for the exact drill remain authoritative.
Get the Configuration Right Before You Order
If your holes are 34–42 mm and your site is air-limited, the YT28 is the logical reference point. If your pattern extends to 43–45 mm, the YT29A is the model to evaluate—but only after confirming that the air system, drill string, taper, air leg, and accessories match the quoted configuration.