Solid Carbide Head SDS-Max Drill Bits Manufacturer (Heavy-Duty Reinforced Concrete) | Zhonghuan

SDS-Max Solid Carbide Head Is the Heavy-Duty Premium Tier

SDS-Max sits a regime above SDS-Plus: hammers in the 5 kg class and beyond, impact energy 10-20 J per stroke, diameters to 50 mm, working lengths to 1200 mm, and applications dominated by reinforced concrete with frequent rebar exposure. The same engineering logic that drives full carbide head adoption in SDS-Plus applies here, but more strongly — the cost of carbide tip detachment or hole-diameter drift is much higher when the bit is being run in a 13 kg demolition hammer drilling 40 mm anchor holes through a structural slab.

An honest engineering note before the program details. One-piece full carbide construction earns its cost where the carbide blank and the head-to-body weld are economical — up to about Ø25 mm. That is why our full carbide program concentrates at SDS-Plus Ø6-25 mm, and why at SDS-Max diameters the volume answer across the industry, ours included, is the heavy brazed 4-cutter on 42CrMo. The full solid carbide head — the one-piece construction class Bosch SpeedXtreme and Hilti TE-CX also use — is in production with us as ZHMAX-8: a resistance-friction-welded one-piece carbide head with no braze joint to crack, to Ø25. One-piece carbide is a sub-Ø25 construction by physics — even Bosch SpeedXtreme stops near Ø25 — so above it the heavy duty runs as the brazed 6-cutter ZHMAX-168 or segmented ZHMAX-7, not a one-piece head. The real overclaim to flag is any one-piece solid-carbide SDS-Max sold past ~Ø28. Everything below — grades, body steel, inspection, the sample path — is the heavy SDS-Max program we ship today, for OEM partners benchmarking Diablo Rebar Demon SDS-Max, DeWalt SDS-Max Elite, or Bosch SpeedXtreme SDS-Max.

SDS-Plus vs SDS-Max — What Changes

Recommended OEM Range — the Heavy SDS-Max Program (Brazed 4-Cutter)

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

SDS-Max sees rebar more often and harder than SDS-Plus, so grade selection skews toward toughness:

• YG11C / K30-K40 equivalent — 10–11% cobalt, the standard premium choice for SDS-Max and the ultra-tough specification for structural anchor and rebar-heavy demolition where chipping is the failure to avoid. Tougher than YG8C, with slightly faster wear in clean concrete, but the trade is worth it for rebar-rich applications.
• YG8C / K20 equivalent — 8% cobalt, available for buyers who prioritise hole life in non-rebar concrete (e.g., older structures, prestressed slabs without surface rebar).

For full background see carbide grade selection guide. Most OEM SDS-Max programs lock YG11C as the standard line; YG8C is a split-SKU option for specific low-rebar channels.

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

1. Carbide grade specification — YG8C / YG11C declared, traceable to carbide supplier batch.
2. Carbide head hardness — HRA 88-90 typical for YG11C; higher for YG8C.
3. 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.
4. Body steel certification — 42CrMo mill certificate traceable to melt batch.
5. 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.
6. 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.
7. Optional shot peening verification — Almen strip residual stress measurement on flute walls if specified.

Sample Order Path

1. 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).
2. We confirm carbide grade (YG11C standard or YG8C split), body steel (42CrMo standard), and shot peening option.
3. Sample run produces 3-4 representative diameters (typical 18, 25, 32 mm) with full inspection package; physical samples shipped.
4. Buyer verifies dimensional, runout, life test data, and tactile feel under representative drilling conditions.
5. 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.
• Carbide grade preference: YG11C standard, YG8C lower-rebar applications, or split SKU.
• 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.