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HNCarbide offers a 55HRC center drill specially optimized for carbon steel and alloy steel machining. Made from wear-resistant material with a precise 60° center drill angle, this tool forms a rigid center drill hole that keeps the main drill from walking, improves hole concentricity and reduces chipping at the cutting edge.
This 55HRC center drill tool is ideal for medium-hard steels in turning centers and CNC machines, delivering stable performance in both roughing and finishing operations. Controlled center drill dimensions and consistent center drill sizes make it easy to match your programs, drawings and center drill size chart requirements.
Grade HN40 is made from submicron WC powder, some speclal additlves added to optimize theproperties with good combination of hardness and toughness.
Its suitable for making drills and miling tools for machining stainless steel, tool steel and heat-resistingalloys.
| Grade | Cobalt content % | Grain size | Density g/cm³ | Hardness HRA | Hardness HV30 | MPa Transverse rupture strength | MPa ·m1/2 Fracture toughness MPa ·m1/2 |
|---|---|---|---|---|---|---|---|
| HN40 | 10 | 0.8 | 14.45 | 91.8 | 1,580 | 3,600 | 11.8 |
| Scientific name | Composition | Physical properties | Features | Typical applications |
|---|---|---|---|---|
| TiSiN | Ti (titanium): main element, forms TiN nanocrystalline phase. Si (silicon): usually 6–10%, forms amorphous Si₃N₄ phase, refines grains and increases hardness. N (nitrogen): combines with Ti and Si to form a composite structure. | Colour: TiSiN coatings usually appear bronze or dark grey-bronze; exact colour depends on Si content, deposition process (such as PVD) and thickness (1–4 μm). Hardness: 34–42 GPa (≈3400–4200 HV). Friction coefficient: 0.3–0.6 (against steel). Temperature resistance: 1000–1200°C (oxidation resistance). Coating thickness: 1–5 μm (typically 2–3 μm). Deposition temperature: 200–400°C (suitable for carbide tools). | Ultra-high hardness: amorphous Si₃N₄ phase suppresses dislocation movement, giving much higher hardness than TiN (~23 GPa) and TiAlN (~35 GPa). High-temperature stability: suitable for dry cutting and high-speed machining (e.g. quenched steels HRC 60+). Anti-adhesion: reduces built-up edge when machining aluminium alloys, stainless steels and other sticky materials. | Tool coatings: drills, mills (especially suitable for PCB routers, tool life increased by 2–3 times). High-speed cutting of quenched steels, titanium alloys and high-nickel alloys. Mould strengthening: die-casting moulds and stamping dies, improving wear resistance. Industrial parts: piston rings and other high-temperature wear parts. |
A center drill is shorter and stiffer, with a pilot and chamfer designed mainly for starting holes and turning between centers. A spot drill is usually longer, with a single-point angle, and is used mainly to “spot” locations for drilling. For tight runout and shaft work, a center drill is usually preferred.
The center drill depth should be enough to form a full chamfer that supports the following tool, but not so deep that the pilot becomes weak. As a guide, many machinists follow a simple center drill depth vs diameter rule (for example, chamfer diameter ≈ 1.5–2× pilot diameter). Ask us if you need a center drill depth calculator or chart.
We offer assorted center drill set solutions that cover popular sizes for toolrooms and production lines. Sets can include mixed HSS center drill and carbide center drill or be customized to your common shaft and hole sizes.
Yes. We can produce non-standard tools according to your drawings, samples or machining requirements (material, coating, size, tolerance and application). Our engineers will evaluate and provide a quotation and lead time.
For serious buyers and distributors, we can offer free standard samples if in stock. Usually you only need to cover the freight cost. For customized tools, a sample fee may apply, which can be refunded or deducted in bulk orders.
Yes.
Regional or customer protection based on sales targets, avoiding price wars among our partners.
Catalogs, brochures, product photos, technical data sheets, online materials.
For key partners, joint promotion, exhibitions and digital marketing support.
Safety stock for fast-moving items and forecast-based production.
Priority production and regular shipments to reduce stock-out risk.
Clear quality warranty policy, quick response to claims.
Replacement, credit or other solutions after confirmation of issues.
Tool selection and cutting parameter advice.
Problem analysis for different materials and machines.
Online training, documents, and when possible, on-site support for key accounts.
HNCarbide offers a 55HRC center drill specially tuned for aluminum and non-ferrous alloys. With a sharp cutting edge and polished flutes, this tool forms a clean center drill hole that prevents the main drill from walking, improves concentricity and minimizes built-up edge when machining aluminum at high spindle speeds.
The tool features a precise 60° center drill angle, controlled center drill dimensions and consistent center drill sizes, making it easy to match your programs, drawings and center drill size chart requirements. Optimized rake and clearance geometry help achieve bright surface finish on aluminum while reducing burrs at the hole entry.
Available in HSS center drill and carbide center drill versions, our 55HRC center drill tool supports both inch and metric center drill standards. HNCarbide can provide matched center drill sets for production use and recommend suitable center drill speeds and feeds for your aluminum grades and CNC setups.
Grade HN40 is made from submicron WC powder, some speclal additlves added to optimize theproperties with good combination of hardness and toughness.
Its suitable for making drills and miling tools for machining stainless steel, tool steel and heat-resistingalloys.
| Grade | Cobalt content % | Grain size | Density g/cm³ | Hardness HRA | Hardness HV30 | MPa Transverse rupture strength | MPa ·m1/2 Fracture toughness MPa ·m1/2 |
|---|---|---|---|---|---|---|---|
| HN40 | 10 | 0.8 | 14.45 | 91.8 | 1,580 | 3,600 | 11.8 |
A center drill is shorter and stiffer, with a pilot and chamfer designed mainly for starting holes and turning between centers. A spot drill is usually longer, with a single-point angle, and is used mainly to “spot” locations for drilling. For tight runout and shaft work, a center drill is usually preferred.
The center drill depth should be enough to form a full chamfer that supports the following tool, but not so deep that the pilot becomes weak. As a guide, many machinists follow a simple center drill depth vs diameter rule (for example, chamfer diameter ≈ 1.5–2× pilot diameter). Ask us if you need a center drill depth calculator or chart.
We offer assorted center drill set solutions that cover popular sizes for toolrooms and production lines. Sets can include mixed HSS center drill and carbide center drill or be customized to your common shaft and hole sizes.
Yes. We can produce non-standard tools according to your drawings, samples or machining requirements (material, coating, size, tolerance and application). Our engineers will evaluate and provide a quotation and lead time.
For serious buyers and distributors, we can offer free standard samples if in stock. Usually you only need to cover the freight cost. For customized tools, a sample fee may apply, which can be refunded or deducted in bulk orders.
Yes.
Regional or customer protection based on sales targets, avoiding price wars among our partners.
Catalogs, brochures, product photos, technical data sheets, online materials.
For key partners, joint promotion, exhibitions and digital marketing support.
Safety stock for fast-moving items and forecast-based production.
Priority production and regular shipments to reduce stock-out risk.
Clear quality warranty policy, quick response to claims.
Replacement, credit or other solutions after confirmation of issues.
Tool selection and cutting parameter advice.
Problem analysis for different materials and machines.
Online training, documents, and when possible, on-site support for key accounts.
HNCarbide center drill tools are used wherever accurate hole starting is critical – from engine shafts and hydraulic parts on the lathe to precision fixtures on CNC machining centers. As a lathe center drill or cnc center drill, they create a rigid center drill hole that keeps twist drills and boring tools on position, reducing drill walk and improving runout on steel, stainless steel, aluminum and cast iron.
Our range covers common 60° and 82° center drill angle styles for turning between centers, drilling tap holes, preparing countersinks and other center drill vs spot drill applications. With clear center drill size and center drill dimensions markings, you can quickly match tools to your print or center drill size chart and standardize setups across the shop.
Each HNCarbide center drill tool is produced on advanced CNC grinders to maintain precise center drill geometry, concentricity and smooth cutting edges. Controlled standard center drill dimensions and tight tolerances on diameter, pilot length and chamfer angle help ensure consistent alignment and a clean center drill hole even at higher spindle speeds.
We offer both HSS center drill and carbide center drill options, as well as inch and metric center drill types in line with DIN 332 / ISO 6411 standard center drill sizes. Optimized flutes support reliable chip evacuation, while recommended center drill speeds and feeds from HNCarbide help you achieve long tool life and stable performance in continuous production.
We Are Commited To Providing High-Quality, Customized solutions At An Affordable price While Also Prioritizing sustainability And ExcellentCustomer Service, These Qualities Make Us A Great choice For Your Center Drill Needs
We Only Use unground tungsten carbide rods with HlP sintering and100% virgin material. Our grade includes lsO K05 to K40, frommachining carbon steel to aluminium, non-ferrous metals andtitanium or we develop grade for your applications.
As a HNCarbide customer, you can enjoy five-axis high-precisiongrinding machines from Australia’s ANCA or Germany’s Walter. Themodern workshop with constant temperature and humidity ensuresthe accuracy of each Center Drill.
Each of your tungsten Center Drill will be sandblasted to effectively remove burrs and improve the finish.
All HNCarbide’s Center Drill will be monitored on WALTER HELICHEEK andZOLLER GENlUS 3 to ensure that every dimension is qualified. We arecommitted to controlling the tolerance within 3 UM.
At HNCarbide, every shipment is meticulously packaged to ensure your tools arrive intact.
Each HNCarbide’s Center Drill is individually placed in a shock-resistant protective case, labeled with complete specifications, and sealed in moisture-proof packaging material before being boxed.
Large-volume orders are reinforced with double-wall cardboard boxes or wooden crates to maximize safety during international shipping.
We collaborate with reliable logistics partners to ensure goods are delivered quickly and securely to their destination via air freight, sea freight, or express courier.
A center drill is shorter and stiffer, with a pilot and chamfer designed mainly for starting holes and turning between centers. A spot drill is usually longer, with a single-point angle, and is used mainly to “spot” locations for drilling. For tight runout and shaft work, a center drill is usually preferred.
The center drill depth should be enough to form a full chamfer that supports the following tool, but not so deep that the pilot becomes weak. As a guide, many machinists follow a simple center drill depth vs diameter rule (for example, chamfer diameter ≈ 1.5–2× pilot diameter). Ask us if you need a center drill depth calculator or chart.
We offer assorted center drill set solutions that cover popular sizes for toolrooms and production lines. Sets can include mixed HSS center drill and carbide center drill or be customized to your common shaft and hole sizes.
Yes. We can produce non-standard tools according to your drawings, samples or machining requirements (material, coating, size, tolerance and application). Our engineers will evaluate and provide a quotation and lead time.
For serious buyers and distributors, we can offer free standard samples if in stock. Usually you only need to cover the freight cost. For customized tools, a sample fee may apply, which can be refunded or deducted in bulk orders.
Yes.
Regional or customer protection based on sales targets, avoiding price wars among our partners.
Catalogs, brochures, product photos, technical data sheets, online materials.
For key partners, joint promotion, exhibitions and digital marketing support.
Safety stock for fast-moving items and forecast-based production.
Priority production and regular shipments to reduce stock-out risk.
Clear quality warranty policy, quick response to claims.
Replacement, credit or other solutions after confirmation of issues.
Tool selection and cutting parameter advice.
Problem analysis for different materials and machines.
Online training, documents, and when possible, on-site support for key accounts.
When you want accurate holes and long tool life, the first step is not the twist drill – it’s the center drill. Many machinists learn this early, but still search for clear information on what is a center drill, how center drill dimensions work and what size center drill to use for different jobs. This guide walks through geometry, sizes, standards and practical tips so you can pick the right center drill tool for your lathe or CNC machine.
A center drill is a short, rigid combined drill and countersink used to start holes accurately. It creates a small pilot and chamfer so the following drill or live center runs true. Compared with drilling directly, using a lathe center drill or cnc center drill:
reduces drill walking on curved or rough surfaces
improves concentricity and runout
reduces chipping on expensive carbide drills
gives a clean chamfer at the hole entry
If you have ever typed “what is a center drill bit” or “what is a center drill used for” while fighting poor hole location, the answer is simple: use a center drill first, then drill or bore.
The most important geometric feature is the center drill angle. The two common standards are:
60 degree center drill – used mainly for turning between centers and general hole starting
82 degree center drill – used when the chamfer will act as a countersink for inch flat-head screws
Standards such as DIN 332 center drill and ISO 6411 center drill define the pilot diameter, body diameter, overall length and chamfer angle. Shops that follow these standard center drill dimensions get predictable results and easier tool replacement.
Modern tools often come with precision-ground relief and polished flutes to improve chip evacuation. Good geometry reduces chatter, gives a smooth surface in the center drill hole, and allows you to use higher RPM without burning the point.
Center drills are usually labeled with a number: #1 center drill, #2 center drill, #3 center drill, #4 center drill, etc. Each number corresponds to a set of fixed dimensions – pilot diameter, body diameter and length. For example, common charts list:
2 center drill dimensions – a typical medium size for many shafts
3 center drill dimensions – for larger shafts and heavier centers
4 center drill dimensions – for robust support or preparing big holes
These standard values are shown in any center drill size chart pdf. If your print calls for a specific chamfer diameter, you can match it to the chart instead of guessing.
Inch and metric center drill systems both exist. Metric prints sometimes refer to metric center drill dimensions according to DIN 332 center drill dimensions. Inch-based shops usually work from “number” sizes such as #1–#5. When buying tools, check whether you need:
center drill sizes metric (DIN / ISO style)
or inch-based standard center drill sizes used in North America and many other regions
Having a full center drill set with the most common numbers avoids downtime when a job suddenly calls for a different pilot size.
Material choice strongly affects tool life and cost.
HSS center drill tools are:
economical
forgiving in less rigid setups
suitable for mild steel, aluminum and general-purpose work
Carbide center drill and carbide center drill bit designs are:
much harder and wear resistant
ideal for stainless, hardened steel and abrasive materials
better suited to high-speed CNC production
Some manufacturers also offer 55–60 HRC grades that bridge the gap between conventional HSS and solid carbide. In any case, combining the right material with standard center drill specs gives predictable performance.
A common question is center drill vs spot drill or “spotting drill vs center drill”. They are not the same tool:
A center drill has a small pilot followed by a larger chamfer. It is very short and stiff. It excels at supporting a live center or starting holes on the lathe.
A spot drill has a single point angle (often 90° or 120°) and no small pilot. It is used mainly on CNC mills to mark hole locations before drilling.
For turning shafts between centers or when using a live center, always choose a center drill because the pilot and chamfer are designed to support the center. For purely milling applications you may spot drill instead, but many shops still prefer a cnc center drill for extra rigidity on small parts.
Selecting what size center drill to use depends on three main factors:
Shaft diameter or hole size
Thin shafts need a small tool such as #1 center drill so the chamfer does not weaken the part.
Larger shafts can use #2 center drill, #3 center drill or bigger for stronger support.
Live center or following tool
The chamfer diameter should be slightly larger than the point of the live center or next drill.
Use your center drill size chart (or center drill size chart pdf) to match the size.
Machine rigidity and material
For delicate setups, a smaller pilot and shallow chamfer reduce cutting forces.
For hardened materials, a carbide center drill with slightly larger pilot improves tool life.
If you standardize on a small set of sizes – for example #1, #2 and #3 – you can cover most work simply by changing the depth and angle in the program.
Running too fast or too slow shortens tool life. That’s why many shops use a center drill speeds and feeds calculator as a starting point. General tips:
Run a bit slower than you would for a full-size twist drill of the same material.
Use plenty of coolant, especially with a carbide center drill in stainless or hardened steel.
Feed steadily; dwelling at the bottom can chip the fine pilot.
Published charts and center drill speeds and feeds tables are good guides, but you should always fine-tune based on your machine, material and required surface finish.
Depth control is important as well. Too shallow and the live center or drill will not seat correctly; too deep and you risk breaking the small pilot. Many machinists follow simple center drill depth vs diameter rules, or program a fixed chamfer diameter instead of a simple depth value.
A well-chosen center drill solves many downstream problems: wandering drills, poor alignment, damaged cutting edges and ugly burrs. By understanding center drill angle, standard center drill dimensions, the difference between HSS center drill and carbide center drill, and how center drill sizes metric or inch-based numbers work, you can build a more reliable process for both lathes and CNC machining centers.
HNCarbide offers complete center drill set solutions in inch and metric standards, following DIN 332 center drill dimensions and ISO 6411 center drill requirements. Whether you need general-purpose HSS tools or long-life carbide options, selecting the right center drill at the start of the operation is the simplest way to protect your drills, improve quality and keep production running smoothly.
Before you go, please note that we offer the most up-to-date industry research reports and the most comprehensive product catalogs, so please contact us if you are interested!
Before you go, please note that we offer the most up-to-date industry research reports and the most comprehensive product catalogs, so please contact us if you are interested!
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