Description
This countersink drill bit set gives you 12 titanium coated HSS countersinks in six sizes from 6mm to 19mm, all on a 1/4 inch hex shank, for $41.78. Each bit is a 90 degree five flute cutter, which is the angle standard wood and chipboard screws are made to, so screw heads finish flush with the surface instead of sitting proud.
The problem a countersink solves is small but constant. Drive a flat head screw straight into timber and the head either sits above the surface, where it catches on everything, or it crushes its way in and tears the fibres around the hole. Neither looks right and on softwood the second one weakens the joint. A countersink cuts a shallow cone for the head to seat into, and once you have used one you notice the difference on every project. The reason to buy a set rather than a single bit is that screw head diameters vary, and a countersink that is too small will not let the head sit flush while one that is too large leaves a visible ring around it.
Specifications
| Quantity |
12 pieces, supplied as 2 sets of 6 |
| Material |
High speed steel (HSS) |
| Coating |
Titanium coated |
| Cutting angle |
90 degrees |
| Flutes |
5 |
| Shank |
1/4 inch hex |
| Sizes |
6mm, 8mm, 9mm, 12mm, 16mm, 19mm |
| Suitable materials |
Wood, plywood, particle board, fibreboard, plastic, aluminium board |
What's in the Box
| 2 x |
Sets of 6 countersink drill bits (6, 8, 9, 12, 16 and 19mm) |
| 12 |
Bits in total |
Why Choose This Countersink Drill Bit Set
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Six sizes covered - 6mm through 19mm handles everything from small cabinet screws up to heavy structural fixings without guessing.
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1/4 inch hex shank - drops straight into an impact driver or a quick change chuck, so you can swap between drilling and countersinking without opening the chuck each time.
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Five flute cutting head - more cutting edges than a single flute countersink means a smoother cone and noticeably less chatter in softwood.
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Titanium coated HSS - the coating reduces friction and heat at the cutting edge, which is what keeps an edge sharp through repeated holes.
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Two full sets - twelve bits rather than six means a spare of every size, so one blunted or lost bit does not stop the job.
What Is a Countersink Bit and When Do You Need One?
A countersink is a cone shaped cutter that widens the top of an already drilled pilot hole so a flat head screw can sit level with or just below the surface. You need one any time the screw head would otherwise stand proud - shelving, cabinet carcasses, decking, flat pack repairs, drawer runners, hinges, anywhere something else has to sit flat on top of the fixing. You do not need one for pan head, button head or dome head screws, which are designed to sit on the surface. On hardwood a countersink is close to essential, because forcing a flat head in without one will split the grain around the hole rather than compress it.
Which Countersink Size Matches Your Screw?
Match the countersink to the diameter of the screw head, not the thread. Measure the widest part of the head with a ruler or vernier and pick the bit that is the same or very slightly larger. As a rough guide, a common 8 gauge wood screw has a head around 8mm across, so the 8mm or 9mm bit is right, while a 6mm bit suits small hinge and cabinet screws and the 16mm and 19mm bits are for coach screws and large washers. The safest method is to test on an offcut of the same timber first and check the head sits flush before you go near the finished piece.
Why Do Countersinks Chatter and How Do You Stop It?
Chatter is the juddering that leaves a scalloped ring instead of a smooth cone, and it happens when the cutting edges bite unevenly. Three things cause most of it. Speed that is too high is the first - countersinking wants a slower speed than drilling, and backing the drill off will often fix it on its own. Too much downward pressure is the second, since the bit needs to shave rather than be forced. The third is a pilot hole that is loose enough to let the bit wander, which is why a countersink cuts cleanest when the pilot hole is the correct size for the screw shank. A five flute head like these bits helps because more cutting edges are in contact at any moment, but technique still matters.
Buyers are typically people building or repairing something in timber - flat pack furniture that has been taken apart and reassembled, shelving, decking, a shed, or cabinetry where the screw heads will be visible or need to be filled over. Tradespeople buy the larger sizes for structural fixings and washers. It is also a common purchase for anyone who has just bought an impact driver and is putting together a starter set of accessories, since the hex shank means these bits work directly with it.
Our tools and hardware collection has the drills, drivers and fixings that go alongside these bits, and essentials covers the general workshop consumables. For garage and shed storage, see storage and organisation, and home and garden for outdoor project supplies.
Frequently Asked Questions
Do these bits drill the pilot hole as well?
No. These are countersinks only, not combination pilot and countersink bits. Drill the pilot hole first with a standard twist bit, then countersink the top of it.
Will they fit an impact driver?
Yes. The 1/4 inch hex shank fits standard impact drivers and quick change chucks, as well as a normal drill chuck.
Can I use these on metal?
They are rated for aluminium board and plastic alongside timber products. They are not intended for steel or stainless steel, where a countersink designed for hard metals and a much slower speed is needed.
Why 90 degrees and not 82?
90 degrees is the standard angle for metric wood and chipboard screws, which is what most screws sold in Australia are. An 82 degree countersink matches imperial machine screws and is a different tool.
What does the titanium coating actually do?
It lowers friction and helps the bit run cooler at the cutting edge, which slows down how quickly the edge dulls. It is a surface coating, so it wears at the tip over time with heavy use.
Are the two sets identical?
Yes. You receive two sets of the same six sizes, giving twelve bits in total.
Do they come in a storage case?
Packaging is supplied by the manufacturer and is intended for transport rather than long term storage. If you want the bits kept in order, a small parts organiser is a worthwhile addition.
Fast Australian Shipping
We ship from within Australia to Sydney, Melbourne, Brisbane, Perth, Adelaide, Hobart, Canberra and Darwin, as well as to regional addresses in every state and territory. Orders are dispatched promptly on business days and tracking is provided once your parcel is on its way.
Product specifications are supplied by the manufacturer and may vary slightly between production runs. Cutting tools are sharp - wear eye protection when drilling and keep out of reach of children.
