SDS-Max is the heavy-duty rotary hammer standard. If you are importing, distributing, or specifying SDS-Max drill bits, this page gives you every standard diameter from 14 mm to 80 mm in a single table — with overall length, working length, carbide grade recommendation, and minimum hammer energy. No other source has all of this data consolidated in one place.
What the SDS-Max Shank Means for Bit Selection
The SDS-Max shank is 18 mm in diameter with an insertion length of 90 mm. Compare this to SDS-Plus: 10 mm diameter, 40 mm insertion length. The longer 90 mm insertion zone transfers impact energy across a much larger contact area, which does two things:
- Reduces shank fatigue: The longer engagement distributes stress along more of the shank, preventing the fatigue cracking that SDS-Plus shanks experience at high joule ratings.
- Enables higher energy classes: SDS-Max hammers typically operate at 5–20 J (examples: Hilti TE 60 at 10 J, Bosch GBH 7-46 DE at 8.5 J, Makita HR4003C at 9.5 J). SDS-Plus hammers top out at around 4 J in most professional models.
This energy class difference is the reason SDS-Max bits require a different carbide grade than SDS-Plus bits of the same diameter. SDS-Max is not simply a larger SDS-Plus — it is a fundamentally different energy class, and the carbide must match.
Key shank dimensions at a glance
- Shank diameter: 18 mm (SDS-Plus: 10 mm)
- Insertion length: 90 mm (SDS-Plus: 40 mm)
- Slot type: two open slots (SDS-Plus: two closed grooves)
- Hammer energy range: 5–20 J (SDS-Plus: 0.5–4 J)
Complete SDS-Max Size Chart (14–80 mm)
The table below covers every standard SDS-Max diameter in production. Dimensions follow DIN and major manufacturer standards. Use the OAL column to verify machine clearance and the WL column to confirm your maximum drilling depth per pass.
| Diameter (mm) | Overall Length (mm) | Working Length (mm) | Recommended Carbide Grade | Min. Hammer Energy |
|---|---|---|---|---|
| 14 | 200 | 100 | YG8C | 3 J |
| 16 | 200 | 100 | YG8C | 3 J |
| 18 | 250 | 150 | YG8C | 3 J |
| 20 | 250 | 150 | YG8C | 4 J |
| 22 | 250 | 150 | YG8C | 4 J |
| 24 | 320 | 200 | YG11C | 5 J |
| 26 | 320 | 200 | YG11C | 5 J |
| 28 | 370 | 250 | YG11C | 5 J |
| 30 | 370 | 250 | YG11C | 6 J |
| 32 | 370 | 250 | YG11C | 6 J |
| 35 | 450 | 330 | YG11C | 6 J |
| 38 | 450 | 330 | YG11C | 7 J |
| 40 | 450 | 330 | YG11C | 7 J |
| 45 | 550 | 420 | YG11C | 8 J |
| 50 | 550 | 420 | YG11C | 8 J |
| 55 | 600 | 460 | YG11C | 9 J |
| 60 | 600 | 460 | YG11C | 9 J |
| 65 | 600 | 460 | YG11C | 10 J |
| 68 | 600 | 460 | YG11C | 10 J |
| 76 | 600 | 460 | YG11C | 12 J |
| 80 | 600 | 460 | YG11C | 12 J |
Lengths shown are standard series. Extended/deep-hole variants available on request. OAL and WL tolerances: ±5 mm. Hammer energy recommendations are minimums for productive drilling in C25/30 concrete.
Carbide Grade by Diameter: Why It Changes
The carbide grade used in an SDS-Max drill tip is not a marketing decision — it is a materials science requirement driven by the impact energy the tip must survive. The three grades used across the SDS-Max range are YG8C and YG11C. The number refers to the cobalt (Co) content by weight percentage; the “C” suffix denotes a coarse grain structure optimised for impact resistance.
| Grade | Co% | HRA | TRS (MPa) | Suited Diameter | Hammer Class |
|---|---|---|---|---|---|
| YG8C | 8% | ~89.5 | ~2400 | 14–22 mm | 3–5 J |
| YG11C | 11% | ~87.5 | ~2800 | 24–80 mm | 5–8 J+ |
Higher cobalt content raises the transverse rupture strength (TRS) — the material’s resistance to fracture under a bending or impact load — while modestly reducing hardness (HRA). This is the correct trade-off for percussive drilling:
- At 14–22 mm / 3–5 J: YG8C provides sufficient impact resistance. Its higher hardness gives better abrasion resistance against concrete aggregate, which is the dominant wear mechanism at smaller diameters where impact stress per unit area is lower.
- At 24–40 mm / 5–8 J: The carbide tip area grows and so does the absolute impact force per strike. YG11C’s higher TRS (~2800 MPa) prevents the subsurface microcracks that would accumulate in YG8C and eventually cause tip spalling.
- At 45–80 mm / 8 J+: At this energy level, YG8C will microcrack and fracture at the carbide-tip interface within a relatively small number of holes. YG11C absorbs the impact without fracturing because its TRS (~2800 MPa) is high enough to withstand the peak stress. The modest hardness reduction does not matter because hole diameter, not hardness, now dominates drilling speed.
Practical implication for buyers
When sourcing SDS-Max bits, always verify the carbide grade specification in the product data sheet. A supplier quoting YG8C for a 50 mm SDS-Max bit is either making a specification error or substituting a lower-cost grade that will fail prematurely in the field. Insist on YG11C for all diameters 45 mm and above.
SDS-Max vs SDS-Plus: The Overlap Zone (20–26 mm)
Both SDS-Plus and SDS-Max drill bits are available in the 20–26 mm diameter range. The standard industry rule is to switch from SDS-Plus to SDS-Max above 26 mm. However, application conditions can push that crossover point down significantly.
In hard concrete (C40+ grade, heavily reinforced), the practical crossover is closer to 20 mm:
- At 20 mm in C40+ concrete, SDS-Plus bits (10 mm shank) begin showing shank fatigue within approximately 50 holes. The smaller shank cross-section cannot transfer the repeated high-energy impacts without accumulating micro-deformation at the shank slots.
- SDS-Max 20 mm bits last 3–5 times longer in the same application because the 18 mm shank distributes the impact stress over a much larger area.
- The specification sheet says the crossover is 26 mm. The jobsite — in hard, reinforced concrete — says the real crossover is 20 mm.
Decision rule for the 20–26 mm overlap zone
- C25/C30 concrete, standard reinforcement, fewer than 200 holes: SDS-Plus is adequate and costs less.
- C40+ concrete, heavy reinforcement, or high hole count: Specify SDS-Max, even at 20–22 mm. The longer shank life will more than offset the higher bit cost.
- Above 26 mm in any concrete class: SDS-Max only. SDS-Plus shanks cannot handle the torque at this diameter.
What to Specify When Ordering
To avoid specification errors and ensure you receive the correct product, provide all of the following when placing an order for SDS-Max drill bits:
- Diameter — in millimeters, taken from the size chart above.
- Overall length (OAL) — confirm against the standard series in the chart, or specify your required custom length.
- Working length (WL) — the usable drilling depth. This must match your application depth requirement.
- Carbide grade — specify YG8C (14–22 mm), YG11C (24–40 mm), or YG11C (45–80 mm). Do not leave this unspecified; some suppliers will substitute a lower grade without disclosure.
- Tip geometry — specify 2-cutter or 4-cutter:
- 2-cutter: Standard for general-purpose concrete. Lower cost, good penetration rate in non-reinforced concrete.
- 4-cutter (cross-head): Better performance in reinforced concrete and harder aggregates. Recommended for diameters 28 mm and above.
- Shank finish — specify raw steel or black-oxidised. Black oxide provides mild corrosion protection and is the standard for branded products. Raw finish is lower cost for OEM/unbranded stock.
Zhonghuan manufactures SDS-Max drill bits across the full 14–80 mm range in both 2-cutter and 4-cutter configurations, with YG8C and YG11C carbide grades. Extended-length and deep-hole variants are available on request. Contact us with your specifications for pricing and lead times.
Related Procurement Programs
If you are sourcing this product line for a distributor, importer, or private-label channel, these OEM and wholesale programs cover the procurement questions buyers usually ask next.
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