Best 90 Degree Hss Countersink Bit (2026)

Specs compared

Specifications are manufacturer rated, as published on each listing and collected 23 October 2026. All five bits cut a 90-degree countersink; the differences are material, flute count, size range and shank.

What the listings tell you, and what they leave out

We read five countersink listings for this guide. None of the five states a warranty term, so every pick scores zero on warranty. Two are M35 cobalt HSS (ColumPRO and Vouyar), two are plain HSS (Chiloskit and the OCGIG’s HSS 4241), and the COMOWARE is the odd one out: its title says high speed steel, but its bullets and spec table say high carbon steel, so we scored it as the weaker steel.

Flute counts run from 1 to 5, and the listings tie flutes to chip clearing rather than speed. Hardness limits are rare: the Chiloskit rates its bits for workpieces under 45HRC and says they are not great for stainless steel, while the OCGIG limits its set to materials under 25 degrees hardness. The Vouyar and ColumPRO are the only two that claim stainless steel outright. Two listings warn against hand drills: the OCGIG says a hand drill shakes and hurts the chamfer, and the Chiloskit is not recommended for hand drills either, so a bench drill is the steadier home for these bits.

Buying guide: the best 90 degree hss countersink bit

HSS, cobalt or titanium coating

Plain HSS cuts wood, plastic and mild steel. Cobalt HSS (M35) holds up on stainless steel and hard alloys, which is why the ColumPRO and Vouyar sit at the top of the ranking. Titanium coating, as on the OCGIG, adds surface hardness to HSS but does not turn it into cobalt. If you only cut wood and plastic, plain HSS or even high carbon steel does the job.

Flutes: 1, 2, 3 or 5

The OCGIG has a single flute, the Vouyar 2, the Chiloskit and ColumPRO 3, and the COMOWARE 5. More flutes spread the cut and clear chips differently, but the listings agree on one thing: the enlarged spiral flutes exist to keep chips from clogging the cut. Do not read too much into the count; match it to the material instead.

Shank and drill type

The COMOWARE’s 1/4-inch hex shank drops into quick-change chucks and most power tools. The OCGIG and Chiloskit use round shanks, the Vouyar a 6 mm round shank, and the ColumPRO straight shanks. Two listings warn off hand drills for these bits, so plan on a bench drill for the steadiest chamfers. For more cutting tools, see the CNC tooling hub and our best CNC router bits.

Size range and screw sizes

Sets cover ranges, not single sizes: the ColumPRO and OCGIG each span 2 to 20 mm in four bits, the Chiloskit 6.3 to 20.5 mm in six, the COMOWARE 6 to 19 mm plus a center punch, and the Vouyar a single 2 to 5 mm bit. Pick the range that covers the screw heads you drive most; a single bit is fine if you always drive the same screw.

Project Match

• Metal enclosures and brackets: the ColumPRO 4-piece set or the Vouyar single bit, the two listings that claim stainless steel.
• Wood signs, boxes and shop jigs: the COMOWARE 7-piece set for soft materials, or the Chiloskit set for harder workpieces under 45HRC.
• Plastic parts: the OCGIG set, rated for metal, wood and plastic in one box.
• One screw size, many holes: the Vouyar single bit covers 2 to 5 mm without buying a set.

How the scores add up

Each bit is scored out of 10 on performance, build, value, safety and warranty. A spec the listing does not publish scores nothing.

Scores run from 9.2 to 9.8: each product’s point total is placed on that range, so more points always means a higher score. Safety counts only for powered gear or where the listing states safety features; where it does not apply, the score is taken over the remaining 90 points.

FAQ: lasers and CNC

What does a countersink bit do?

It cuts a cone-shaped recess at the top of a drilled hole so a flat-head screw sits flush with or below the surface. All five bits here cut a 90-degree cone, the standard angle for flat-head screws.

How do you use a countersink drill bit?

Drill the pilot hole first, then run the countersink bit at the top of the hole to cut the seat, and drive the screw. The ColumPRO listing describes this order: use after pre-drilling for screws, or for deburring holes and chamfering edges. A bench drill gives the steadiest result; two listings warn that a hand drill shakes and hurts the chamfer.

What size countersink bit do I need for a #9 screw?

Match the bit’s countersink range to the screw head, not the shank. The sets here cover 2 to 5, 5 to 10, 10 to 15 and 15 to 20 mm per bit, so pick the bit whose range seats the head fully. When in doubt, the Chiloskit’s six sizes from 6.3 to 20.5 mm give the finest steps.

Can I use a countersink bit in a hand drill?

The Vouyar’s 6 mm round shank fits hand drills and bench drills, and the ColumPRO works with cordless drills and impact drivers. But the OCGIG and Chiloskit listings warn against hand drills, saying the bit shakes and the chamfer suffers. For the cleanest seats, use a bench drill.

Do countersink bits work on stainless steel?

Only the bits rated for it. The Vouyar and ColumPRO listings claim stainless steel and hard alloys; the Chiloskit says its bits are not great for stainless steel. Match the bit’s stated material to your workpiece, and use lubrication and cooling on hard alloys as the Vouyar listing advises.

Related: the CNC tooling hub, our best CNC router bits, the best end mills for aluminum, the best CNC bit sets for beginners and the best router bits for plastic.