Choosing the wrong drill bit wastes time, destroys materials, and burns through bits at alarming speed. This guide covers every major drill bit type manufactured today — from SDS hammer bits for concrete to diamond-tipped bits for porcelain tile. For each type you will learn what it is, what specs matter, what materials it handles (and what it does not), and the most common mistakes that cause premature failure. Two decision tables at the end let you jump from your material or job scenario straight to the correct bit.
Zhonghuan Tools manufactures SDS-Plus, SDS-Max, hammer chisels, and HSS twist drill bits at our factory in Zhejiang, China. Where a topic goes deeper than this overview allows, we link to a dedicated article on our site.
SDS Hammer Drill Bits (SDS-Plus & SDS-Max)
SDS hammer drill bits are the professional standard for drilling concrete, reinforced concrete, masonry block, and natural stone. The key feature is the SDS shank — a slotted system that locks into a rotary hammer and transmits percussive energy directly to the carbide tip while allowing the bit to slide axially inside the chuck.
Two shank families exist:
- SDS-Plus — 10 mm shank with 4 grooves. Fits rotary hammers up to roughly 4 kg / 3.5 J. Covers drill diameters from 4 mm to 26 mm. The most common system for construction, electrical, and HVAC trades.
- SDS-Max — 18 mm shank with 5 grooves. Fits heavy-duty rotary hammers from 5 kg upward (5-27 J). Covers diameters from 12 mm to 52 mm and beyond. Required for deep anchoring, core drilling, and heavy demolition.
Key specs to look for: Carbide grade (YG8C for standard concrete, YG11C or cross-tip 4-cutter for reinforced concrete), head geometry (2-cutter for speed, 4-cutter for precision and rebar tolerance), flute design (single-flute for fast chip evacuation in deep holes, double-flute standard), and overall length (DIN 8039 standard vs. extra-long DIN 8040).
Works on: Concrete, reinforced concrete, masonry block, brick, natural stone, aerated concrete.
Does NOT work on: Metal (carbide tip is blunt, not a cutting edge), wood (tears fibres instead of cutting), tile or glass (impact shatters them).
Common mistake: Using pure rotation mode on concrete — carbide tips dull within seconds without hammering action. Conversely, using hammer mode on tile or glass destroys the workpiece instantly.
Deep Dive: SDS-Plus vs SDS-Max Comparison Guide →
Deep Dive: Complete Concrete Drilling Guide →
Round-Shank Masonry Bits
Round-shank (cylindrical shank) masonry bits fit standard 3-jaw keyless chucks on conventional drills. They have the same brazed carbide tip as SDS bits but rely on the drill's internal hammer mechanism for percussion — which delivers far less impact energy than a dedicated rotary hammer.
Key specs: Shank is smooth round (no SDS grooves), tip is usually a single carbide plate (2-cutter). Lengths follow DIN 8039. Available from 3 mm to 16 mm diameter.
Works on: Brick, aerated block, lightweight concrete, mortar joints. Adequate for hanging picture frames, curtain rails, and light anchors in masonry.
Does NOT work on: Dense reinforced concrete (insufficient impact energy), granite or hard natural stone, any material requiring pure rotation.
Common mistake: Attempting to drill hard concrete with a round-shank bit in an impact drill. The bit overheats, the carbide tip cracks or detaches, and the hole barely progresses. If you are drilling more than a few holes in concrete, switch to an SDS-Plus rotary hammer.
HSS Twist Drill Bits
High-Speed Steel (HSS) twist drill bits are the most widely used drill bit in the world. The helical flute design evacuates chips while the ground tip shears material with a rotating cutting edge. HSS bits handle a huge range of materials — from softwood and plastic to mild steel and aluminium — making them the default choice for general-purpose drilling.
Three main manufacturing grades:
- Rolled HSS — The bit is formed by rolling, then heat-treated. Adequate for softwoods, plastics, and mild steel. Lower cost, shorter service life, wider tolerances. Common in consumer-grade sets.
- HSS-G (Ground) — After hardening, flutes and point are precision-ground on a CNC grinder. This produces sharper cutting edges, tighter diameter tolerances (h8), and significantly longer tool life. HSS-G is the professional standard and is specified in DIN 338 (jobber length) and DIN 340 (long series).
- HSS-E (Cobalt-alloyed) — Contains 5-8% cobalt added to the steel matrix. Covered in the next section.
Key specs to look for: Point angle (118 degrees standard for general use, 135 degrees split point for harder metals and self-centering), material grade (entry-level HSS budget, entry-level HSS/M2 professional, M35/M42 cobalt), coating (black oxide, TiN, TiAlN), and DIN standard (DIN 338 jobber, DIN 340 long, DIN 1869 extra-long parabolic flute).
Works on: Mild steel, aluminium, copper, brass, cast iron, softwood, hardwood, plastic, fibreglass, plywood.
Does NOT work on: Concrete or masonry (dulls instantly — no carbide tip), stainless steel (use cobalt instead), hardened steel above 40 HRC (use cobalt M42), ceramic tile or glass (shatters them).
Common mistake: Running too-high RPM on steel. HSS overheats above approximately 600 degrees Celsius, losing its hardness permanently. Use the correct RPM chart and apply cutting fluid on ferrous metals.
Deep Dive: HSS Material Grades Guide (rolled HSS vs HSS-G vs Cobalt) →
Deep Dive: Fully Ground vs Rolled Drill Bits →
Deep Dive: Drill Bit Coatings Explained →
Cobalt Drill Bits (M35 / M42)
Cobalt drill bits are HSS bits with 5-8 percent cobalt alloyed into the steel itself (not a coating). The cobalt raises the red-hardness temperature, allowing the bit to maintain a sharp cutting edge at temperatures where standard HSS would soften and fail. This makes cobalt bits essential for stainless steel, titanium, Inconel, and other heat-resistant alloys.
Two common grades:
- M35 (5% cobalt) — Handles most austenitic stainless steels (304, 316), medium-carbon steel, and heat-treated alloys up to roughly 35 HRC. The workhorse grade for professional metal fabrication.
- M42 (8% cobalt) — For the toughest jobs: Inconel, Hastelloy, hardened steel up to 45 HRC, and heavily work-hardened stainless. Higher cost but dramatically longer life in extreme conditions.
Key specs: Always look for a 135-degree split point — it self-centers without a pilot hole and reduces the axial thrust that causes work-hardening. Parabolic flutes (DIN 1869) improve chip evacuation in deep holes. Avoid cobalt bits with 118-degree conventional points on stainless — they walk and work-harden the surface.
Works on: Stainless steel (all grades), hardened steel (up to 45 HRC with M42), titanium, Inconel, Hastelloy, cast stainless, and tool steel.
Does NOT work on: Concrete or masonry (wrong mechanism), wood (overkill and expensive), tile or glass.
Common mistake: Using too-high RPM. Cobalt bits need slow speed and steady feed pressure. Dwelling (spinning without advancing) on stainless steel work-hardens the surface, making the next pass even harder. Apply cutting oil generously.
Deep Dive: Cobalt M35 vs M42 — Which Grade for Which Alloy? →
Deep Dive: 135° Split Point vs 118° Conventional — When It Matters →
Wood Drill Bits (Selection by Hole Type)
Dedicated wood bits are engineered around timber grain, chip evacuation, and exit-edge quality. Zhonghuan no longer presents the old wood-bit subfamilies as standalone product pages; wood drilling requests should be confirmed by project specification instead of treated as catalogue stock.
Selection logic: define the hole diameter, depth, bottom shape, exit tear-out tolerance, shank requirement, and whether the operation needs a guide point or press setup.
Key specs: centre spur sharpness, flute geometry, shank type, steel grade, allowable RPM, and whether the bit is intended for handheld drilling or drill-press use.
Works on: softwood, hardwood, plywood, MDF, chipboard, and laminated timber when the tool geometry matches the hole.
Does NOT work on: metal, concrete, tile, or glass.
Common mistake: running a large wood-boring tool too fast without clamping the workpiece. Always secure the workpiece and reduce speed as diameter increases.
Tile & Glass Bits
Ceramic, porcelain, and glass are extremely hard but brittle. They demand bits with no percussive action, very low RPM, and specialised tip geometry that scores rather than impacts.
Three main types:
- Spear-Point Carbide Bits — A tungsten carbide arrowhead tip designed for ceramic wall tile. The spear geometry concentrates pressure on a tiny contact point, scoring through the glaze before enlarging the hole. Use at 400-600 RPM with light pressure. Suitable for standard ceramic tile up to about 8 mm thick.
- Diamond Core Bits — Hollow cylinders with diamond grit bonded to the cutting edge. Required for porcelain tile (which is much harder than ceramic), natural stone (marble, granite), and thick vitrified tile. Water cooling is essential to prevent overheating and extend diamond life. RPM 300-600 depending on diameter.
- Glass Drill Bits — Spear-point tungsten carbide tip specifically ground for the extreme brittleness of glass. Use with cutting fluid (water or light oil) and very light pressure. Start at an angle to create a nick, then straighten up.
Works on: Ceramic wall tile, porcelain floor tile, mosaic tile, glass pane, mirror, marble, granite (diamond only).
Does NOT work on: Metal (wrong tip geometry), wood (unnecessary), concrete (no impact mechanism).
Common mistake: Using hammer/impact mode — this shatters tile and glass instantly. Always set the drill to rotation-only mode. Another frequent error is pressing too hard on porcelain, which cracks the tile from the back.
Deep Dive: Glass & Tile Drill Bit Guide →
Step Drill Bits
Step drill bits (also called stepped cone bits or Unibit-style bits) are conical HSS tools with multiple stepped diameters ground into a single body. One step bit can replace an entire set of twist bits for sheet-metal work, making them extremely popular in electrical, HVAC, and automotive trades.
Key specs: Material (HSS M2 standard, M35 cobalt for stainless sheet), coating (TiN gold is most common for reduced friction), step count, step size increments (1 mm or 2 mm), and maximum diameter. Straight-flute designs are standard; spiral-flute designs cut more aggressively and handle thicker stock.
Works on: Sheet metal (mild steel, aluminium, copper) up to 3 mm thick, electrical knockout boxes, plastic panels, fibreglass, thin stainless steel (with cobalt variant).
Does NOT work on: Thick plate (anything above about 4 mm), concrete, wood (leaves rough holes), tile or glass.
Common mistake: Trying to step-drill thick steel plate. Step bits are designed for sheet metal — once the material thickness exceeds the step height, the bit cannot transition to the next diameter cleanly and the edge chips.
Deep Dive: How to Choose the Best Step Drill Bit →
Hole Cutters (TCT Wall Cutters & Annular Cutters)
Large-diameter holes now map to the current Zhonghuan lines by material: TCT wall-hole cutters for brick, block, AAC, and light masonry wall openings; diamond core drills for dense concrete or tile; annular cutters for magnetic drilling machines in steel; and HSS step drills for clean sheet-metal knockouts.
Current selection logic:
- TCT wall-hole cutters — carbide teeth brazed onto a steel body for wall penetrations in brick, block, AAC, and light masonry.
- Annular cutters — HSS, cobalt, or TCT cutting edges on Weldon shanks for steel and stainless applications on magnetic drills.
- HSS step drills — stepped cone tools for thin sheet metal, junction boxes, electrical panels, and small cable-gland openings.
Key specs: diameter, cutting depth, tooth or edge material, shank/arbor compatibility, pilot configuration, target substrate, and recommended machine type.
Works on: brick, block, AAC, concrete and tile with diamond core drills, sheet metal with step drills, and steel plate with annular cutters.
Does NOT work on: hardened steel without the correct annular grade, glass without diamond tooling, or structural concrete with a wall-hole cutter.
Common mistake: treating every large circular hole as the same tool category. Match the cutter to the substrate first, then confirm diameter, machine, cooling, and feed pressure.
Hammer Chisels (SDS-Plus & SDS-Max)
Hammer chisels are not drill bits — they are impact tools that fit SDS rotary hammers set to chisel-only mode (no rotation). They are used for demolition, chasing, scaling, and breaking rather than drilling holes.
Common chisel types:
- Flat Chisel (Cold Chisel) — Wide flat blade for breaking concrete, removing tile, and light demolition. Available in SDS-Plus (20-40 mm wide) and SDS-Max (25-80 mm wide).
- Pointed Chisel — Moil point for breaking up concrete slabs, rock, and hard aggregate. Concentrates impact energy on a small point.
- Channel / Groove Chisel — U-shaped profile for chasing cable channels and conduit runs in concrete and masonry walls. Produces a clean, consistent groove width.
- Scaling Chisel (Cranked) — Bent blade for scraping old tile adhesive, render, and coatings from floors and walls. The offset angle keeps your hand away from the work surface.
- Spade Chisel — Wide blade (50-115 mm) for fast material removal in demolition and clay digging. SDS-Max only.
Key specs: Shank type (SDS-Plus or SDS-Max), blade width, overall length, steel grade (chrome-vanadium or chrome-molybdenum for toughness), and hardness (HRC 48-55 typical — too hard and it chips, too soft and it mushrooms).
Works on: Concrete, masonry, tile adhesive, render, morite, rock, clay, asphalt.
Does NOT work on: Metal cutting (use an angle grinder), wood, glass.
Common mistake: Using chisels at too steep an angle. This causes the chisel to dig in and jam. Hold the hammer at a shallow angle (15-30 degrees) and let the impact energy do the work.
Deep Dive: Chisel Types for Hammer Drills — Complete Guide →
Material → Drill Bit Decision Table
Use this table to jump from your target material to the correct bit type, tip specification, and our detailed guide.
| Material | Recommended Bit | Tip / Grade | Guide |
|---|---|---|---|
| Concrete / Masonry | SDS Hammer Drill Bit | Carbide YG8C, 2-cutter | SDS Guide → |
| Reinforced Concrete | SDS 4-Cutter Hammer Bit | Carbide Cross-Tip YG11C | Concrete Guide → |
| Mild Steel | HSS-G Fully Ground Twist | M2 / entry-level HSS, 118° or 135° | HSS Guide → |
| Stainless Steel | Cobalt M35 / M42 | Split Point 135° | Cobalt Guide → |
| Hardened Steel (>40 HRC) | Cobalt M42 | Split Point 135°, TiAlN | Cobalt Guide → |
| Wood (Softwood / Hardwood) | Wood bit by hole type | Project-defined steel | Project spec |
| Ceramic / Porcelain Tile | Spear-Point Carbide / Diamond | Tungsten Carbide / Diamond Grit | Tile Guide → |
| Glass | Diamond / Spear-Point | Diamond Grit / TC Spear | Tile Guide → |
| Sheet Metal (1-3 mm) | Step Drill Bit | HSS M2 / M35 TiN-coated | Step Drill Guide → |
| Large Holes (>20 mm) | Hole Saw / Core Drill | TCT / annulaire | Hole Saw Info → |
Job Scenario → Drill Bit Decision Table
Not sure what you are drilling into? Start from your task and find the recommended bit.
| Scenario | Recommended Bit | Why |
|---|---|---|
| Hanging shelves on a brick wall | SDS-Plus 2-cutter, 6-10 mm | Light masonry; fast drilling with standard rotary hammer |
| Installing expansion anchors in concrete | SDS-Plus 4-cutter | Precise, round holes for tight anchor fit; rebar tolerant |
| Drilling stainless steel handrails | M35 Cobalt, 135° split point | Heat-resistant; self-centering on curved surfaces |
| Running electrical conduit through a panel | Step drill or TCT hole cutters | Large, clean, burr-free holes in sheet metal |
| Deep hole in structural I-beam | DIN 1869 parabolic flute HSS-G | Extra-long reach; parabolic flutes evacuate chips from deep holes |
| Demolition / removing old floor tiles | SDS-Plus or SDS-Max flat chisel | Chisel-only mode; wide blade lifts tiles quickly |
| Drilling through ceramic bathroom tile | Spear-point carbide, 6 mm | No impact; scores through glaze without cracking |
| Boring hinge pockets in cabinet doors | 35 mm flat-bottom wood bit | Flat-bottomed blind hole at exact depth for Euro hinges |
| Drilling cable runs through timber joists | wood-boring bit matched to depth | Self-feeding screw tip; fast in thick timber |
| Chasing cable channels in a concrete wall | SDS-Plus channel chisel | U-profile produces clean conduit grooves |
| Drilling aluminium sheet for rivets | HSS-G 118° or step drill | Aluminium is soft; standard HSS works perfectly at higher RPM |
Interactive Tools & Calculators
Put this knowledge into practice with our free online tools:
- RPM & Feed Speed Calculator — Enter your bit diameter and material to get the recommended RPM, feed rate, and expected drill time.
- SDS Drill Bit Selector — Define drilling condition, SDS shank, diameter and depth to compare current SDS bit architectures.
- Unit Converter & Reference Tables — Convert between mm/inch, look up DIN standard dimensions, and find hardness conversion tables (HRC/HB/HV).
- RPM Speed Chart (Reference Article) — Printable RPM chart for every bit type and material combination.
- DIN Standards Quick Reference — Decode DIN 338, 340, 345, 1869, 8039, and 8040 at a glance.
Need bulk pricing or OEM customization? Zhonghuan Tools supplies SDS-Plus, SDS-Max, hammer chisels, and HSS twist bits to distributors and OEM buyers in 60+ countries. Contact our sales team → for factory-direct quotes, custom packaging, and private-label options.
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.
- Metal & Concrete Drilling Tools Distributor Program — A practical OEM supply program for distributors who need both metal drilling and concrete drilling tools: SDS bits, HSS twist drills, M35 cobalt, step drills…
- Private Label Drilling Tool Set Matrix for Distributors — A private-label set matrix for distributors and tool brands: SDS sets, HSS drill sets, cobalt upgrades, step drill kits, hole saw kits, mixed installer kits…
