Quick Answer: Compare the Geometry, Not Just the Brand
Heller TriJET Ultimate SDS-max and Diager Ultimax 168 both belong in the premium reinforced-concrete conversation, but they do not make the same engineering argument.
Heller TriJET Ultimate is positioned as a premium SDS-Max multi-cutter built around robustness, rebar behaviour, and drilling speed. Heller highlights a brazed multi-cutter carbide head, a double-centre tip, backward-curved cutting edges that avoid snagging on reinforcement, and improved dust removal through the head and helix design.
Diager Ultimax 168, in the available Diager reference sheet, is a SDS-max concrete hammer drill bit with three carbide tips, six cutting edges, a self-centering point, and a progressive flute. The catalogue language is very practical: round and calibrated holes, longer life, and lower blocking risk in hard aggregate or rebar.
So the procurement answer is not Heller good, Diager bad, or the reverse. The better question is: do you need a robust multi-cutter premium story, or a visible 3-plate / 6-edge anti-blocking story?
What Each Bit Actually Is
Heller Trijet Ultimate (SDS-Max). Per Heller's 2025 catalogue, the Trijet Ultimate is a Y-geometry multi-cutter: three carbide plates set at roughly 120° around Heller's patented Trijet tip, with a recessed carbide tip, a double centring tip and a low-vibration triple helix. Heller calls it its best SDS-Max multi-cutter for reinforced concrete; the SDS-Max version was previously sold as the Enduro Y-Cutter and is now consolidated under the Trijet Ultimate name.
Diager Ultimax 168 (ref 168). Diager's 2026 catalogue describes the Ultimax 168 as a 6-cutting-edge SDS-Max head built on 3 self-centering carbide tips ('6-blade technology, 3 self-centering carbide tips') — a brazed multi-cutter: the 3-tip / 6-edge head, with progressive flute and anti-blocking geometry for round, calibrated holes.
So it is two distinct heads: a 3-plate Y multi-cutter with 3 cutting edges (Heller Trijet Ultimate) and a 3-tip / 6-edge multi-cutter (Diager Ultimax 168). They are not the same geometry, and an RFQ that only says '3-cutter' or 'premium SDS-Max' will not capture which one you mean.
Head Geometry Comparison
Two heads, two constructions. Read the last column for the factory-direct equivalent:
| Head | Construction | Edges | Catalogue claim | Our factory-direct equivalent |
|---|---|---|---|---|
| Heller Trijet Ultimate | Brazed Y-cutter, 3 carbide plates at ~120°, patented Trijet tip, recessed carbide, triple helix | 3 (Y) | Best multi-cutter, longest life in reinforced concrete | ZHMAX-7 multi-segment (we don't copy the 3-plate Y) |
| Diager Ultimax 168 (ref 168) | Brazed, 3 self-centering carbide tips | 6 | 6-blade, anti-blocking, round holes | Our ZHMAX 168 (3-block, 6-edge) |
When Each Design Wins
Choose a Heller TriJET Ultimate style benchmark when the target buyer wants a premium SDS-Max line for reinforced concrete, rebar contact, fast drilling, and a simple specialist-brand story. This is the safer benchmark when your channel wants a high-end line that can be compared with other premium European SDS-Max products.
Choose a Diager Ultimax 168 style benchmark when the customer specifically asks for 3-plate / 6-edge geometry, deep-hole stability, calibrated hole quality, or an anti-blocking claim. The geometry is more visually distinctive, but it also needs tighter sample inspection because the performance depends on each cutting edge being placed and supported correctly.
For many distributors, the practical catalogue structure is not one or the other. A clear range can use a standard SDS-Max 4-cutter line for volume, a full carbide head premium line for rebar-rich work, and a 3-plate / 6-edge line (our ZHMAX-168) for round-hole, anti-blocking, deep-hole and hard-aggregate work.
Sample Checks Before You Approve an OEM Version
- Count the head geometry from photos. Ask for top-view, side-view, and 45-degree close-ups. Confirm whether the sample really has three carbide plates and six active cutting edges.
- Ask how the carbide is fixed. Brazed segments, inserted segments, embedded heads, and full carbide heads are different products with different failure modes.
- Measure runout and edge height. A 6-edge head only works if the cutting edges are concentric and share impact load properly.
- Check the carbide grade. For SDS-Max reinforced-concrete work, ask for YG11C, or the agreed equivalent, plus batch traceability.
- Test hard aggregate and rebar contact separately. Blocking in hard stone, dust choking in deep holes, and edge fracture on rebar are different failures.
- Inspect the flute and core. Diager's logic depends partly on progressive flute/core strength; Heller's logic depends partly on dust transport through the head and helix.
Common Failures When OEM Factories Copy Premium SDS-Max Geometry
Almost every premium SDS-Max benchmark we have seen copied in OEM form has at least one of these problems. They are not random quality issues. They are structural mistakes that happen when a factory copies the visual shape without understanding the load path.
- Edge height mismatch on 6-edge designs. The three main plates look correct from above, but the six cutting edges are not at the same height. Only two or three edges actually contact the material. The load concentrates, and the bit wears unevenly or chips early.
- Carbide placement drift. On a 3-plate / 6-edge head, the three carbide inserts must be positioned symmetrically around the centre axis. If one insert is offset by even 0.3 mm, the hole is not round, the bit vibrates under load, and the SDS-Max shank wears faster.
- Brazing quality invisible from outside. An embedded or brazed carbide head can look perfect in a photo. The real test is whether the carbide stays attached after 50 holes in hard aggregate with rebar contact. A bad braze fails suddenly, not gradually.
- Flute strength sacrificed for appearance. Progressive flute designs require careful control of core diameter along the body. If the factory reduces core thickness to make the flute look deeper, the bit is weaker in bending and more likely to break in deep holes.
- Wrong carbide grade for the application. SDS-Max reinforced concrete work generates high impact and heat. A factory using a cheaper, harder grade like YG6 or YG8 instead of the specified YG11C will see more edge fractures on rebar contact.
These are the reasons the sample inspection process matters more than the catalogue claim. A well-made 4-cutter SDS-Max with correct carbide grade and runout is a better product than a badly-made 6-edge SDS-Max with the right shape but wrong internals.
RFQ Wording for a Factory-Direct Benchmark
Do not write: make Heller or make Diager. Write the engineering target.
SDS-Max rotary hammer drill bit for reinforced concrete, benchmark allowed: Heller TriJET Ultimate SDS-max and Diager Ultimax 168 3-plate / 6-edge. Required: carbide head geometry drawing, top-view and side-view sample photos, carbide grade YG11C or agreed equivalent, 42CrMo body, SDS-Max shank, progressive or optimized flute design, runout report, brazing/joint process description, drilling test in concrete with hard aggregate and rebar contact.
If the six-edge geometry is mandatory, add this line:
Head must show three main carbide plates and six active cutting edges, with self-centering point and measurable edge-height consistency before mass production approval.
Zhonghuan View
The 3-plate / 6-edge head — Diager's Ultimax 168 geometry — is squarely within what Zhonghuan builds. Our ZHMAX 168 is that head: three self-centering carbide tips brazed into a forged 42CrMo body, ground into six active cutting edges. This is not a 4-cutter relabelled as '6-edge' — it is the genuine three-plate construction, made to documented geometry and private-labelled to your brand.
The reason we can carry this tier is that we control the four things that decide whether a 6-edge SDS-Max actually drills round and lasts:
- Carbide grade. YG11C (impact-tough) for SDS-Max rebar work, or an agreed grade, with mill-cert traceability on every batch.
- Edge-height consistency. All six edges ground to share the impact load — the difference between a head that drills round and one that only contacts on two or three edges and chips early.
- Tip placement and concentricity. The three carbide plates set symmetrically about the axis with runout measured, so the hole stays round and calibrated and the shank does not wear prematurely.
- Braze integrity. Controlled-atmosphere brazed joints, verified in-house on a metallographic cross-section and a witness cut, so the carbide stays put after repeated rebar contact instead of shearing loose.
For the Heller Trijet's 3-plate Y we don't copy the exact Y geometry; our multi-cutter answer there is the ZHMAX-7 multi-segment head (the Bosch SDS max-7 class). Either way, we still recommend sample approval — round holes, anti-blocking, rebar pass-through, service life — not because the geometry is exotic, but because a sample test is exactly how a buyer separates a correctly-built 6-edge head from a copy that only looks the part. Send the head photos, target diameters and lengths, target market and the failure modes you want to avoid, and we'll build and quote the right head for the job.
