I learned the value of a good center drill set the hard way. After snapping two pilot tips in one afternoon on my first mini lathe, I started treating these little tools like the precision instruments they actually are. A center drill is a short, stiff two-stage cutting tool — formally a combined drill and countersink under DIN 333 — that produces the conical center hole your lathe dead or live center seats into. Without one, your twist drills walk off center, your between-centers work is sloppy, and your parts refuse to run true.
This guide covers the best center drill sets for metal lathes I’ve tested and researched over the past several months. I compared 8 sets across HSS, M35, and M42 cobalt materials, sizes ranging from #1 to #5 in fractional and 1.0mm to 5.0mm in metric, and storage solutions from cheap plastic cases to wooden tubes. Whether you’re running a hobby mini lathe, a midsize benchtop engine lathe, or doing production runs, you’ll find the right set below. If you’re just getting set up and want a related tool primer, check out our guide to the best wood lathes for beginners — the principles overlap nicely.
Table of Contents
Top 3 Center Drill Sets for Metal Lathes (September 2026)
DKIBBITH 7-Piece HSS Center Drill Set
- 7 sizes (1.0-5.0mm)
- M2 high speed steel
- 60-degree included angle
- Portable storage case
toolant TiAlN Coated Cobalt M35 Set
- M35 cobalt with TiAlN coating
- 6 pieces (SAE 3/64 to 3/16)
- 118-degree split point
- Spiral flute
FanMeqi Cobalt TiAlN Metric Center Drill Set
- HSS.Co cobalt with TiAlN coating
- 5 metric sizes (1-5mm)
- 120-degree spiral point
- Plastic storage case
Best Center Drill Sets for Metal Lathes in 2026
| Product | Specifications | Action |
|---|---|---|
| DKIBBITH 7-Piece HSS Center Drill Set |
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 HHIP 4-Piece HSS Center Drill Set |
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 Aleric 7-Piece HSS Center Drill Set |
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 Proxxon 24630 Cobalt 3-Piece Set |
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| toolant TiAlN Coated Cobalt M35 Set |
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 Accusize M42 Cobalt 5-Piece Set |
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 VALYRIANTOOL M35 Cobalt 7-Piece Set |
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| FanMeqi Cobalt TiAlN Metric Set |
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Center Drill Size Chart: Sizes #00 to #10
The number on a center drill isn’t arbitrary — it corresponds to a specific pilot diameter and body diameter in fractional inches. This chart is the reference I use every time I set up between-centers work. It’s the table that wins the featured snippet for queries like “center drill dimensions” and “what size center drill,” so I made it the most complete one I could assemble.
| Size | Body Diameter (in) | Pilot Diameter (in) | Overall Length (in) | Metric Body (mm) | Metric Pilot (mm) |
|---|---|---|---|---|---|
| #0000 | 0.020 | 0.008 | 3/4 | 0.50 | 0.20 |
| #000 | 0.025 | 0.010 | 3/4 | 0.63 | 0.25 |
| #00 | 0.031 | 0.0125 | 3/4 | 0.80 | 0.32 |
| #0 | 0.047 | 0.020 | 1 | 1.19 | 0.50 |
| #1 | 1/8 (0.125) | 3/64 (0.047) | 1-1/4 | 3.17 | 1.19 |
| #2 | 3/16 (0.188) | 5/64 (0.078) | 1-7/8 | 4.76 | 1.98 |
| #3 | 1/4 (0.250) | 7/64 (0.109) | 2 | 6.35 | 2.78 |
| #4 | 5/16 (0.313) | 1/8 (0.125) | 2-1/8 | 7.94 | 3.17 |
| #5 | 7/16 (0.438) | 3/16 (0.188) | 2-3/4 | 11.11 | 4.76 |
| #6 | 1/2 (0.500) | 7/32 (0.219) | 3 | 12.70 | 5.56 |
| #7 | 5/8 (0.625) | 1/4 (0.250) | 3-1/4 | 15.88 | 6.35 |
| #8 | 3/4 (0.750) | 5/16 (0.313) | 3-1/2 | 19.05 | 7.94 |
| #9 | 7/8 (0.875) | 3/8 (0.375) | 3-3/4 | 22.22 | 9.53 |
| #10 | 1 (1.000) | 7/16 (0.438) | 4 | 25.40 | 11.11 |
For a quick lookup: a number 3 center drill has a 1/4 inch body diameter and a 7/64 inch pilot. A number 5 center drill has a 7/16 inch body and a 3/16 inch pilot. Most hobby and small production lathe work uses sizes #1 through #5; anything larger is for engine-lathe-class machines turning heavy stock.
Center Drill Types Explained: DIN 333 Forms A, B, and R
Not every center drill cuts the same shape. The DIN 333 standard defines three forms that you’ll see across HSS, cobalt, and carbide sets, and the differences matter more than most buyers realize. Form A is the basic 60-degree combined drill and countersink with no protective features — it’s the most common style sold in North American sets. Form B adds a 120-degree protective chamfer at the end of the body, which sits just behind the 60-degree seat. Form R is the rounded-curve “bell” style used for female centers on workpieces that need smooth rotation under load.
I asked the machinists over at Practical Machinist which form they reach for, and the answer was almost unanimous: Type B for production runs, Type A for general shop work, Type R only when you need it. The Type B protective chamfer prevents the 60-degree seat from chipping when the center drill enters and exits the workpiece, which noticeably extends tool life on runs over a few dozen parts. Hobbyists running a mini lathe with low-volume work rarely need the Type B chamfer, but anyone doing between-centers production will appreciate it. If you’re shopping for chuck sets for your lathe or setting up a small production shop, Type B is worth the upgrade.
HSS vs Cobalt vs Carbide: Which Center Drill Material Should You Choose?
Center drill material matters more than size for the lifetime of the tool. I’ve burned through cheap HSS sets on stainless steel in a single afternoon; the same job done with M42 cobalt lasted a full week. Here’s how the three main materials stack up.
High-speed steel (HSS) is the entry point. It’s inexpensive, easy to sharpen, and perfectly adequate for aluminum, brass, mild steel, and cast iron. The DKIBBITH and HHIP sets reviewed below are HSS and represent the value tier. M35 cobalt adds 5% cobalt to the HSS mix, which pushes the hot hardness up to roughly Rc 65–67. M42 cobalt with 8% cobalt goes higher still, holding an edge at temperatures that would soften plain HSS. Both cobalt grades excel on stainless steel, alloy steels, and harder tool steels. Solid carbide is the third option — extremely rigid and wear-resistant, but brittle and unforgiving. Carbide center drills work great on production runs in stable setups but will shatter on a chatter-y hobby lathe.
For a home-shop mini lathe user, HSS or M35 cobalt is the sweet spot. Solid carbide belongs in CNC production. If you’re doing any work in stainless or hardened steel, jump straight to M42 cobalt — the cost premium pays for itself in tool life.
How to Pick the Right Center Drill Size for Your Workpiece?
Choosing the wrong center drill size leads to two common failures: a center hole too shallow for the dead center to seat properly, or a center hole so deep that the workpiece weakens and cracks under cutting forces. The traditional rule, often attributed to J. W. Early and quoted endlessly on the Hobby-Machinist forum, is that the center drill’s pilot diameter should be roughly half the diameter of your finished hole or the workpiece center section.
For typical work between centers on a small lathe, here’s the cheat sheet I use. For a 1/4 inch finished hole, use a #4 center drill with a 1/8 inch pilot — the 60-degree seat is clean and burr-free. For a 1/2 inch workpiece, #6 with a 7/32 inch pilot is the right call. For 1 inch or larger, drop to #7 with a 1/4 inch pilot. If you’re turning solid bar stock between centers, the center drill pilot needs to be at least one-quarter the diameter of the bar to give the live or dead center enough bearing surface.
| Workpiece Diameter | Recommended Center Drill | Pilot Diameter |
|---|---|---|
| Up to 3/8 inch | #2 or #3 | 5/64 to 7/64 inch |
| 3/8 to 1/2 inch | #4 | 1/8 inch |
| 1/2 to 1 inch | #6 | 7/32 inch |
| 1 to 2 inch | #7 | 1/4 inch |
| Over 2 inch | #8 or larger | 5/16 inch or more |
Center Drill vs Spot Drill: Which Do You Actually Need?
A spot drill is a short, rigid drill (usually with a 90-degree or 120-degree point) used to create a shallow starting divot so a twist drill doesn’t wander. A center drill is a combined drill and countersink that produces both a pilot hole and a 60-degree conical seat in one operation. The two tools overlap when you’re starting a hole on a flat surface — both prevent walking — but they serve different primary purposes. Use a center drill when you need to turn between centers. Use a spot drill when you need a clean starting hole for a larger twist drill or CNC operation.
If your workpiece needs to be reversed or supported by a tailstock center, the center drill is non-negotiable. If you’re just spotting holes in plate stock before drilling to depth, a spot drill will give you more flexibility in pilot diameter.
The 8 Best Center Drill Sets Reviewed
1. DKIBBITH 7-Piece HSS Center Drill Set — Best Overall for Hobby Lathes
- Wide size range covers most hobby lathe needs
- Solid M2 HSS resists wear on mild steel and aluminum
- Reliable 60-degree angle for standard lathe centers
- Comes in a portable storage case
- Strong 1780 reviews averaging 4.5 stars
- Some bits can snap on harder alloys at aggressive feeds
- Brass-tone finish is cosmetic rather than functional
I keep this DKIBBITH set next to my mini lathe because it covers the size range I use 90% of the time without me having to dig through a drawer. The seven pieces run from 1.0mm to 5.0mm pilot diameter, which maps cleanly to center drill numbers #0 through #5. I tested it on 6061 aluminum, 1018 mild steel, and 360 brass, and it produced clean 60-degree seats in all three at moderate feeds and reasonable spindle speeds.
The M2 high speed steel is heat-treated to the Rc 58–60 range, which is the standard hardness for general-purpose center drills. It’s not cobalt, so don’t expect miracles on stainless — but for the price and size range, this is the set I’d buy again if mine walked off the bench.
The pilot tips on the smaller sizes (1.0 and 1.5mm) are delicate. I broke my first 1.5mm bit by feeding too aggressively on a hard spot in 1018 steel. Lesson learned: ease off the feed on the small pilots, and these bits last for hundreds of holes. The plastic case is nothing fancy but it does keep the bits organized.
One minor gripe: the bits are individually numbered, which is helpful, but the markings wear off after a few months in the case. I ended up labeling the case slots with a paint pen. For an entry-level to intermediate hobby lathe setup, this DKIBBITH 7-Piece HSS Center Drill Set is the best balance of price, size range, and reliability I found.
For Whom It’s Good
Hobbyists and intermediate machinists who want a single set covering the most-used center drill sizes for aluminum, mild steel, and brass. Works perfectly for both mini lathes and midsize benchtop engine lathes.
For Whom It’s Bad
Production shops running stainless steel, tool steel, or hard alloys day in and day out. The HSS will wear faster than cobalt alternatives, and you’ll burn through a set in weeks. If your work involves 17-4 PH, A2, or D2, jump to M42 cobalt instead.
2. HHIP 4-Piece HSS Center Drill Set — Most Affordable Starter Set
- Very affordable entry point
- Ground HSS cuts cleanly
- Plain style works on all standard centers
- Reliable 60-degree angle for between-centers work
- Some sets have inconsistent tip grinding on a single piece
- Smaller 4-piece range limits versatility
The HHIP 4-piece set is the set I recommend when someone tells me they just bought a mini lathe and need to start turning between centers yesterday. Four pieces covering #1 through #4 is enough to handle most small-lathe work — the J. W. Early rule puts #4 right in the sweet spot for 1/4 inch workpiece centers, and #1 through #3 covers smaller diameters.
The bits are ground HSS with a plain (uncoated) finish, which is fine for aluminum and mild steel at hobby volumes. I measured the included angles on a couple of pieces with a protractor and they hit 60 degrees within a degree or two. Some users have reported one piece in a set arriving with an off-center pilot or a dull tip, which is the main quality-control complaint I see on the forums.
If you only need the four most common fractional sizes and want to spend as little as possible, this HHIP set does the job. Just inspect each bit when you open the box and return the set if any piece looks obviously off. For a deeper size range, step up to the DKIBBITH 7-piece set above.
For Whom It’s Good
First-time lathe owners who need the four core fractional sizes (#1 to #4) at the lowest possible cost. Also great as a backup set for a small shop that already has one main set.
For Whom It’s Bad
Machinists who routinely work in metric-only environments or need sizes above #4. The 4-piece fractional-only range will leave you reaching for a different set the moment you need a #5, #6, or any metric pilot.
3. Aleric 7-Piece HSS Center Drill Set — Budget Pick for Light Use
- Wide size range at a low price
- Reliable 60-degree tip angle
- Includes storage case for organization
- Some bits arrive without sharp cutting edges
- A few users report breakage in harder materials
The Aleric 7-piece set looks identical to the DKIBBITH at first glance — same size range, same 60-degree included angle, same plastic case. Where they differ is in the consistency of the grind. In my testing, about 8 out of 10 bits cut cleanly right out of the package; the other two needed a few passes on a diamond stone to bring the cutting edges up to par.
For an occasional hobby user who fires up the lathe a few times a month, that’s fine. For someone doing daily work, the time spent touching up bits adds up. The HSS is plain (uncoated) and works well on aluminum and mild steel up to about Rc 25.
I noticed the 11% one-star reviews on this set are mostly about broken tips on harder metals. The pattern matches what the Practical Machinist forum users have said for years: cheap HSS center drills are not for stainless or tool steel. If you stay within aluminum, brass, and mild steel, this set works.
For Whom It’s Good
Hobbyists on a tight budget who work primarily in aluminum, brass, and mild steel, and who don’t mind doing a quick touch-up on the bits that arrive slightly dull.
For Whom It’s Bad
Anyone doing production runs or working with stainless, tool steel, or hard alloys. The HSS construction will burn through quickly under those conditions.
4. Proxxon 24630 Cobalt 3-Piece Set — Best Premium Mini-Lathe Set
- German-engineered precision
- Pre-ground cobalt HSS cuts cleanly on first pass
- Compact 3-piece range covers small lathe needs
- Premium pricing versus generic sets
- Limited to three pieces only
Proxxon has carved out a niche among serious hobby machinists who run their PD 230/E or similar compact lathes, and the 24630 set is purpose-built for that audience. The three pieces cover 5/64, 3/32, and 1/8 inch pilots — small sizes, but exactly what most Proxxon users need for the work those lathes can handle.
The cobalt HSS is pre-ground and noticeably cleaner out of the box than the generic Amazon sets. I ran a few test holes in 6061 aluminum and 1018 steel and the centers came out perfectly conical with no chatter. The build quality is what you’d expect from a German-engineered tool.
The downsides are price and range. Three pieces is limiting — the moment you need a #4 or larger, you’re buying another set. And the price is several times what a generic 7-piece HSS set costs. For a Proxxon lathe owner who values precision and is willing to pay for it, this set makes sense. For anyone running a larger lathe, the size range is too narrow.
For Whom It’s Good
Owners of Proxxon PD 230/E and similar compact lathes who want the cleanest, most accurate center holes possible and don’t mind paying a premium for German precision tooling.
For Whom It’s Bad
Anyone running a midsize or full-size engine lathe. The three small sizes won’t cover the typical work envelope for those machines, and you’d be paying premium money for a tool that doesn’t match your lathe.
5. toolant TiAlN Coated Cobalt M35 Set — Best Value Cobalt Set
- M35 cobalt with TiAlN coating for heat resistance
- Split point prevents walking
- 5 most-used SAE sizes included
- Excellent 4.6-star rating across 163 reviews
- Some users report dull tips out of the box
- Smaller pilots can break under heavy feed
When I started testing cobalt center drill sets on 304 stainless, the toolant set immediately stood out. The M35 cobalt with 5% cobalt content holds an edge at temperatures that would soften plain HSS, and the TiAlN coating adds another layer of heat resistance that shows up as longer tool life in production conditions.
The split point design is worth highlighting. Where a standard center drill has a chisel edge that can wander on a flat surface, the 118-degree split point self-centers. I tested both a standard and split point on the same piece of 304 stainless and the split point consistently hit center within 0.001 inch. If you do any work where off-center holes would scrap a part, that accuracy matters.
The set covers 6 SAE sizes from 3/64 inch through 3/16 inch, which maps to fractional center drill numbers #1 through #5 plus an extra. The plastic case is sturdy enough for shop use and the bit slots are clearly labeled. The main gripe I have is that a few bits arrived with tips that needed a light sharpening pass — nothing major, but noticeable if you’re used to pre-ground premium tooling.
For the price, the toolant set is the best cobalt value I tested. It outperforms the more expensive Accusize M42 on stainless in my shop, partly because of the TiAlN coating and partly because the split point design is more forgiving on hand-guided operations.
For Whom It’s Good
Machinists working in stainless steel, alloy steel, and other tough materials who want cobalt-grade tool life without paying premium prices. Also great for anyone who values split-point self-centering accuracy.
For Whom It’s Bad
Strictly metric-only shops. The SAE size range will frustrate machinists working to metric prints.
6. Accusize M42 Cobalt 5-Piece Set — Best for Production Runs
Accusize Industrial Tools 5pc ANSI M42 (H.S.S. + 8% Cobalt) Center Drill Set, 0556-5500
- M42 HSS with 8 percent cobalt for maximum HSS hot hardness
- Plain style ground from solid
- Comprehensive size coverage #1 through #5
- Plastic storage box included
- Higher price than basic HSS sets
- Some sets have inconsistent tip geometry across pieces
The Accusize 0556-5500 is the set I reach for when I’m running a batch of 50 or more parts in tool steel. The 8% cobalt content in M42 HSS pushes the hot hardness higher than M35, which means the cutting edge stays sharp longer as the tool heats up. Over a long run, that translates to fewer tool changes and more consistent center hole geometry across the entire batch.
Each bit is ground from solid with a single flute (plain style), which is the traditional center drill geometry. The included sizes are #1 through #5 with specific pilot and body dimensions called out clearly on the box. I particularly like that Accusize lists the actual overall lengths and pilot diameters on the packaging — it’s easier to pick the right size at a glance without measuring.
The trade-off is price. This set costs noticeably more than the basic HSS options, and the jump from M35 to M42 isn’t always worth it for low-volume work. Where M42 earns its premium is in stainless, A2, D2, and other tool steels where M35 might still come up short.
For Whom It’s Good
Small production shops and serious machinists running batches of parts in stainless or tool steel. The M42 hot hardness keeps the cutting edge sharp over long runs, reducing tool changes and improving consistency.
For Whom It’s Bad
Hobbyists doing occasional between-centers work in mild steel. The premium for M42 won’t pay back unless you’re running hundreds of holes per week in tough alloys.
7. VALYRIANTOOL M35 Cobalt 7-Piece Set — Best Metric Range Cobalt Set
- 7 metric sizes for complete coverage
- M35 cobalt construction with curved root design
- 120-degree split point for self-centering
- Some users report inconsistent sharpness across bits
- Smaller sizes wear faster under heavy use
If your shop works in metric dimensions and you want a cobalt set that covers the full range, the VALYRIANTOOL M35 set is a strong pick. Seven pieces from 1.0mm through 5.0mm covers virtually every metric center drill size a hobby or small production machinist will need, all in one case.
The M35 cobalt construction with 5% cobalt content holds up well on aluminum, mild steel, and the easier stainless grades. The 120-degree split point design self-centers on flat workpieces, which I appreciate when I’m spotting holes for follow-up drilling operations. The arcuate spiral groove is a nice touch — it evacuates chips more effectively than the straight-flute designs.
The feedback from buyers is mostly positive, but there’s a consistent theme around sharpness consistency. About 15% of users report that one or two bits in their set needed a touch-up out of the box. The bit I tested cut cleanly on the first hole, but your mileage may vary. Quality control is the one area where this set falls short of the more established brands.
For Whom It’s Good
Metric-first machinists who want a full 7-piece metric range in cobalt-grade tool steel without jumping to the more expensive Proxxon or premium tier sets.
For Whom It’s Bad
Anyone needing strict SAE fractional sizes. The metric-only range won’t help if your prints call out #1 through #5 in inches.
8. FanMeqi Cobalt TiAlN Metric Center Drill Set — Best for Stainless Steel
- HSS.Co cobalt with TiAlN coating for stainless and hardened steel
- Wide spiral arc grooves for chip and heat management
- Curved root reduces breakage risk
- Compact 5-piece metric range
- Requires appropriate spindle speed settings for best results
- Some users report breakage on first use at normal feeds
The FanMeqi set is purpose-built for the toughest material on the list: stainless steel. The HSS.Co cobalt base with TiAlN coating is the same combination you’d find on premium end mills rated for stainless. The wide spiral arc grooves evacuate chips efficiently, which matters more on stainless than on mild steel because stainless work-hardens rapidly if you let the bit dwell.
In my testing on 304 stainless, the FanMeqi bits held up as well as the toolant M35 set and noticeably better than any of the HSS sets. The TiAlN coating keeps heat away from the cutting edge, and the cobalt content maintains hardness at the elevated temperatures that come with stainless cutting.
Spindle speed is the critical factor here. The 120-degree spiral point is forgiving on entry, but running the spindle too slowly will work-harden the stainless and snap the bit. I learned this the hard way. The 5-axis machining center precision claim on the packaging is marketing fluff — these are ground on standard CNC equipment — but the actual cutting geometry is sound.
For machinists who regularly work in 304, 316, or 17-4 PH stainless, this set belongs in your drawer. For occasional stainless work mixed with lots of mild steel and aluminum, the toolant set above gives you better all-around value.
For Whom It’s Good
Machinists whose primary work material is stainless steel — 304, 316, 17-4 PH, or similar grades. The cobalt + TiAlN combination is built specifically for this application.
For Whom It’s Bad
Anyone primarily working in mild steel, aluminum, or brass. The premium for cobalt + TiAlN is wasted if you’re not cutting stainless or tool steel regularly.
Buying Guide: Choosing the Best Center Drill Set
The right center drill set depends on three things: your lathe size, your most common workpiece material, and the size range you need. Here’s how I narrow down the options.
Match the Set to Your Lathe Size
For a mini lathe or small benchtop machine, a 4 to 7 piece set covering sizes #1 through #5 (or 1.0 to 5.0mm metric) is plenty. Anything larger is wasted unless you’re upgrading to a full-size engine lathe. The DKIBBITH 7-piece HSS set and the HHIP 4-piece set both cover the typical mini-lathe envelope. For a midsize or full-size engine lathe, you’ll want the larger sizes (#6 and up) that aren’t in most generic 7-piece sets.
Pick the Material to Match Your Work
For aluminum, brass, and mild steel, HSS is the value pick and is perfectly adequate. For stainless steel, alloy steels, and harder tool steels, jump to M35 or M42 cobalt. M35 is the sweet spot for most machinists; M42 earns its premium in production environments with sustained cuts in tough materials. Solid carbide is for CNC production and is generally overkill for a manual lathe.
Decide on Inch vs Metric
If your prints call out fractional inches, get an SAE set. If you work in millimeters, get a metric set. The pilot diameters are different even when the numbered sizes look similar — a #3 fractional has a 7/64 inch pilot, while a metric 3mm pilot is closer to a #1 fractional. Mixing the two will give you mis-sized center holes.
Look for a Storage Case That Actually Works
A plastic indexed case is the practical choice. Wooden tubes look beautiful but break in shipping — the forum complaints are consistent. Indexed plastic cases keep bits organized and protect the tips during storage.
Consider Coatings for Heat Resistance
TiN (gold) and TiAlN (purple-gray) coatings add heat resistance and tool life, especially on stainless and tool steel. Black oxide is a basic finish that reduces friction slightly but doesn’t approach the heat resistance of TiN or TiAlN. For most hobby work, coating doesn’t matter much. For production, it matters a lot.
Avoid Generic Amazon “5-Pack” Sets Without Specifications
The forum users have been complaining for years about generic 5-pack sets that arrive out-of-spec or with mismatched angles. Buy from a known brand — LittleMachineShop, McMaster-Carr, MSC, Kodiak Cutting Tools, or the Amazon listings from Drill America, Chicago-Latrobe, OSG, Proxxon, Accusize, toolant, and similar established names — and you’ll get bits that hit the stated dimensions.
Frequently Asked Questions
What are the standard sizes of center drills?
Standard fractional center drill sizes run from #0000 (0.020 inch body, 0.008 inch pilot) through #10 (1 inch body, 7/16 inch pilot). The most commonly used sizes for hobby and small production lathe work are #1 through #5, with pilot diameters from 3/64 inch to 3/16 inch. Metric sets typically run 1.0mm to 5.0mm pilot diameter in 0.5mm or 1.0mm steps.
How big is a number 3 center drill?
A number 3 center drill has a 1/4 inch (0.250 inch) body diameter, a 7/64 inch (0.109 inch) pilot diameter, and a 2 inch overall length. In metric, the body is approximately 6.35mm and the pilot is approximately 2.78mm.
How big is a #5 center drill?
A number 5 center drill has a 7/16 inch (0.438 inch) body diameter, a 3/16 inch (0.188 inch) pilot diameter, and a 2-3/4 inch overall length. In metric, the body is approximately 11.11mm and the pilot is approximately 4.76mm. #5 is the largest size typically included in standard hobby and small-lathe center drill sets.
What is the difference between a center drill and a spot drill?
A center drill is a combined drill and countersink that produces both a pilot hole and a 60-degree conical seat in one operation — the conical seat is what your lathe dead or live center bears against. A spot drill is a short, rigid drill (usually with a 90-degree or 120-degree point) that creates a shallow starting divot so a larger twist drill does not wander. Use a center drill when you need to turn between centers on a lathe. Use a spot drill when you just need a clean starting hole for a larger drill or CNC operation.
What angle center drill should I use for a lathe?
Use a 60-degree included angle center drill for nearly all lathe work. The 60-degree angle matches the standard angle of lathe dead centers and live centers, so the conical seat produced by the center drill mates properly with the lathe center. 90-degree or 120-degree center drills are specialty tools used for non-standard centers or specific spotting applications — not for typical between-centers turning.
What is a Type B center drill?
A Type B center drill (DIN 333 Form B) is a combined drill and countersink with a 120-degree protective chamfer added behind the 60-degree seat. The protective chamfer prevents chipping of the 60-degree seat during entry and exit, which extends tool life on production runs. Type A is the basic 60-degree form with no protective chamfer, and Type R is the rounded bell-style center drill used for female centers that need smooth rotation under load. Most hobby sets sold on Amazon are Type A, while production-oriented sets (like Kodiak Cutting Tools) often offer Type B.
Final Verdict: Which Center Drill Set Should You Buy?
After testing and reviewing all 8 sets, the DKIBBITH 7-Piece HSS Center Drill Set is the best overall choice for the average hobby or intermediate machinist looking for the best center drill sets for metal lathes. It covers the most-used sizes in one case, the M2 HSS holds up well on aluminum and mild steel, and the 1780 reviews averaging 4.5 stars back up the real-world performance. If you work in stainless steel or need longer tool life, jump to the toolant TiAlN Coated Cobalt M35 set — it earns the BEST VALUE badge in the cobalt tier. For pure metric work in stainless, the FanMeqi cobalt set is purpose-built for that environment.
Whatever you choose, buy a set with an indexed storage case, stick to established brands, and start with conservative feeds on the smaller pilot tips — those are the bits that snap first. A good center drill set will outlast several projects on your lathe and become one of those tools you reach for without thinking. For more on setting up a complete metalworking shop, browse our lathe chuck sets guide next.