SDS-Max Solid Carbide Head Is the Heavy-Duty Premium Tier
Our ZHMAX-8 programme brings a one-piece full-carbide cutting head and an RFW head-to-steel joint to heavy reinforced-concrete drilling. Match substrate, reinforcement, hole diameter and working length to the rotary hammer’s rated capacity and operating modes.
We currently supply ZHMAX-8 in SDS-Max Ø4–25 mm, alongside our SDS-Plus full-carbide programme in Ø4–25 mm. These are our programme ranges. Other brands offer larger full-carbide heads, including 32 mm Bosch EXPERT SDS max-8X variants. ZHMAX-7 multi-insert four-cutter and ZHMAX-168 six-edge heads remain separate professional constructions, selected by diameter, machine and application.
SDS-Plus vs SDS-Max — What Changes
| Element | SDS-Plus | SDS-Max |
|---|---|---|
| Hammer class | 2-5 kg, 1-3 J impact | 5-13 kg, 10-20 J impact |
| Shank | 10 mm h9, 40 mm insertion, 4 grooves (2+2) | 18 mm nominal, 90 mm insertion, 5 grooves (3+2) |
| Diameter range | 6-32 mm typical | 16–50 mm typical for the shank system, with specialty sizes by model; our current ZHMAX-8 full-carbide-head programme is Ø4–25 mm |
| Working length | 100-460 mm typical | 200-1200 mm typical |
| Body steel | 40Cr alloy | 42CrMo high-tensile alloy |
| Carbide grade default | YG8C standard | YG8C (ZHMAX-8 full head); YG11C (ZHMAX-7 / ZHMAX-168 inserts) |
Recommended OEM Range — the Heavy SDS-Max Program (Brazed 4-Cutter)
| Diameter | Working Length | Application |
|---|---|---|
| 16, 18, 20 mm | 320, 540 mm | Light anchor, MEP penetration, retrofit |
| 22, 25, 28 mm | 320, 540, 920 mm | Standard structural anchor, post-installed rebar |
| 30, 32, 35, 38 mm | 540, 920 mm | Heavy structural anchor, bridge bearing, deep penetration |
| 40, 45, 50 mm | 540, 920, 1200 mm | Tunnel rock bolt prep, large MEP, bridge anchor |
Most OEM programs lock the 16-32 mm core (eight sizes) and add 35-50 mm sizes by confirmed demand. 1200 mm working length is specialty — quoted on application confirmation.
Carbide Grade Selection for SDS-Max
ZHMAX-8 full-carbide heads use YG8C. For brazed SDS-Max insert heads, carbide grade is matched to the selected model and duty; ZHMAX-7 and ZHMAX-168 retain their specified YG11C insert programs.
Why Body Steel Matters More on SDS-Max
SDS-Plus body deflection over 460 mm is small. SDS-Max body deflection over 920-1200 mm is significant — and any flexure during impact transfers stress into the carbide head joint. This is why SDS-Max body steel typically moves from 40Cr to 42CrMo:
- 40Cr — chromium-alloy steel, standard for SDS-Plus and lighter SDS-Max. Hardens well, machinable, good fatigue life at moderate diameters and lengths.
- 42CrMo — chromium-molybdenum-alloy, higher toughness and fatigue life, better resistance to bending stress under rebar deflection. Standard for SDS-Max above 25 mm and most working lengths above 540 mm.
Optional shot peening on flute walls adds compressive surface stress, increasing fatigue life by 30-50 percent on long bits subjected to repeated bending.
Inspection Package Per Batch
- YG8C full-head grade and batch documentation follow the approved SKU specification.
- Head hardness is checked against the approved YG8C specification and lot record.
- SDS-Max shank verification — check nominal 18 mm lands, three drive grooves, two closed locking grooves, insertion and release against the approved drawing and gauges; record the specified hardness.
- Body steel certification — 42CrMo mill certificate traceable to melt batch.
- Runout at the carbide tip — typical acceptance under 0.3 mm TIR for 540 mm working length, under 0.4 mm for 920 mm, under 0.5 mm for 1200 mm.
- Internal life test on C30 / C35 reinforced concrete with rebar exposure, hole diameter measured at start, midpoint, end of life, drilling depth recorded per pass.
- Optional shot peening verification — Almen strip residual stress measurement on flute walls if specified.
Sample Order Path
- Send target market, channel, benchmark brand (Diablo Rebar Demon SDS-Max / DeWalt SDS-Max Elite / Bosch SpeedXtreme SDS-Max), diameter range, length range, application notes (rebar exposure expected, hammer machine class).
- We confirm the YG8C full head, RFW joint, body steel and packaging for the order.
- Sample run produces 3-4 representative diameters (typical 18, 25, 32 mm) with full inspection package; physical samples shipped.
- Buyer verifies dimensional, runout, life test data, and tactile feel under representative drilling conditions.
- Spec lock + 50-100 piece pre-production sign-off on lower volumes (SDS-Max sample batches are smaller than SDS-Plus because individual unit value is higher), then bulk schedule.
RFQ Checklist
- Diameter and length matrix.
- Send the SDS interface, diameter, length and quantity per size to start the quotation.
- Body steel: 42CrMo standard or 40Cr for lighter SDS-Max.
- Surface treatment: standard, shot-peened flutes, optional black oxide.
- Marking: laser shank marking with size, brand, approved SDS-Max interface drawing reference, batch code.
- Packaging: bulk, individual PVC tube, plastic case, master carton spec.
- Inspection records required.
- Quantity per SKU and reorder cycle.
Quote a Heavy-Duty SDS-Max Program
Send target benchmark brand, diameter and length matrix, carbide grade preference, and application notes. We will reply with sample plan, inspection records, and OEM quotation path.
Request SDS-Max Program Quote