When you're using screws as a fixing, neatness usually demands you use a countersink to seat the heads properly. With the wide range of screws, a countersink drill bit set with a selection of sizes is an economical solution. To help you choose the right one, we've put together a concise guide. We've also made a few recommendations, including our favorite, the DeWalt Countersink Drill Bit Set, which combines the clever design that the brand is known for with the fast, accurate cutting that professionals demand. Considerations when choosing countersink drill bit sets Countersink drill types There are two basic types of countersink drill: standard and all-in-one. Standard The basic model is a conical (or standard) cutter, usually with three to five flutes. More flutes means more cutting edges, usually resulting in a cleaner finish and faster waste clearance. Basic conical countersinks are used when the screw hole has already been drilled. They are also very effective for deburring holes in metal and plastic (many engineers will just give them a quick twist by hand) but they are awkward to line up properly. All-in-one The composite (or all-in-one) countersink are generally easier to line up for precise cuts. This has a standard drill bit with a countersink bit that fits around the shank. It can be used to guide the countersink, or it can drill and countersink or counterbore at the same time. It can also be adjusted for different depths. A variation on the guide bit uses a tapered drill, which helps center the countersink in pre-existing holes, and provides faster cutting. This versatility has made it by far the more common choice in a countersink drill bit set, though conical versions remain popular with engineers and metalworkers. Guide bits aren't usually suitable for drilling metal, so countersinking holes becomes a separate process which the conical cutter is better suited for. Shanks Shanks are either round or hexagonal. Round shanks are designed primarily for inserting in a chuck — either a pillar drill, or a hand-held model. Hexagonal shanks work perfectly well in these chucks, but they are primary intended for slot in, quick-release systems — where loosening and tightening a chuck isn't necessary. Features All countersink bits are made of high speed steel (HSS), though finishes and additives vary. They can have either nickel, black oxide, or titanium nitride (TiN) coatings, which help reduce heat build-up — so they cut better and stay sharp longer — and also resist corrosion. Countersinks specifically made for metal might have tungsten and molybdenum or cobalt added to the steel, making them very hard indeed. Price You won't pay very much for good quality countersink drill bit sets, with prices starting at around $10. From there on up, price largely depends on the quantity and quality of the drill bits, though even metal-cutting tools rarely top $40. The exception is precision-engineered cobalt countersinks, which can exceed $100 — though these will probably last a lifetime. FAQ Q. What is countersink chatter? A. It's coarse vibration and an irregular shape, created when the countersink bit doesn't cut smoothly. It can be caused by a blunt bit or inconsistent drilling pressure. Although it's not always practical, you generally get more consistent, chatter-free results using a drill press rather than a hand-held drill. Q. Is a counterbore the same as a countersink? A. No. A counterbore is a deeper hole, wide enough to take the screw head. It can be used for decorative finishes — hiding the screw head with a dowel — or to join two pieces of material without needing a full-length screw. A countersink is a shallow conical depression — usually just deep enough to make the top of the screw head flush with the surface. Countersink drill bit sets we recommend Best of the best: DeWalt's Countersink Drill Bit Set Our take: Premium quality from one of the top brands, at a very affordable price. What we like: Tapered drill bits and four-blade countersink make for fast cutting in wood, plastics and most composites. Hex shank can be chucked or used with rapid load systems. Drill bits are replaceable. What we dislike: Some quality-control issues. Bits are not always straight. Best bang for your buck: Werkzeug's Countersink Drill Bit Set Our take: Remarkably low-cost set for general woodworking and DIY jobs. What we like: Drill and countersink wood and plastics in one action. Includes seven sizes from three to 10 millimeters. Three-point design helps accuracy. Adjustable counterbore depth. Drills can be used separately. Very cheap. What we dislike: Hex screw thread can strip, making countersinks useless. Choice 3: Irwin's Countersink Drill Bit Set Our take: Comprehensive precision set aimed at metalworkers and engineers. What we like: Includes five pieces from 1/4-inch to 3/4-inch to cover a wide range of tasks. Designed for metals like brass, aluminum, and steel sheet, but perfectly capable in wood, plastics, etc. Nice box. What we dislike: Comparatively expensive, though certainly not overpriced. Bob Beacham is a writer for BestReviews. BestReviews is a product review company with a singular mission: to help simplify your purchasing decisions and save you time and money. BestReviews never accepts free products from manufacturers and purchases every product it reviews with its own funds. BestReviews spends thousands of hours researching, analyzing and testing products to recommend the best picks for most consumers. BestReviews and its newspaper partners may earn a commission if you purchase a product through one of our links. Distributed by Tribune Content Agency, LLC.
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