Guides

How to Drill Stainless Steel Without Ruining the Bit
Stainless work-hardens, which is why bits blunt on it. The technique that works: slow speed, firm pressure, cutting fluid and a sharp cobalt bit — plus stainless drilling speeds. Read more...
Is My Drill Machine SDS Plus or SDS Max? How to Tell — Plus a Model Lookup
Two quick ways to tell whether your drill takes SDS Plus or SDS Max bits, what you can and can't mix, and a model lookup for Makita, DeWalt, Bosch, Milwaukee, HiKOKI, Hilti and more. Read more...
Drill Bit Sets vs Individual Sizes: Which Should You Buy?
Should you buy a drill bit set or buy by the size? When each makes sense, how we sell every type (HSS and cobalt by the size in packs; masonry, wood and specialist bits singly), and why most people do both. Read more...
How to Drill Masonry & Concrete — Masonry Bits vs SDS
Which drill bit and which drill for brick, block and concrete — masonry bits vs SDS, wall-plug drill sizes, and the technique that keeps the tip sharp. From a specialist supplier since 1985. Read more...
M35 vs M42 Cobalt Drill Bits — What's the Difference?
Both are cobalt drill bits, the difference is how much cobalt. M35 (5%) is the everyday step up from HSS for stainless and tough steel. M42 (8%) resists heat and wear even better, for hardened, high-alloy and heavy production work. Read more...
Cobalt vs HSS Drill Bits — Which One for Which Metal?
HSS drill bits are the everyday choice for mild steel, wood, aluminium and plastic. Cobalt bits cost more but resist heat far better, so they're the ones to reach for on stainless, cast iron and hard, tough steels. Here's how to choose. Read more...
Drill Speed Chart — The Right RPM for Every Material and Bit Size
Drilling speed (RPM) chart by material and drill bit diameter, for HSS bits. The bigger the bit, the slower the speed. Stainless runs at roughly half the speed of mild steel — get it wrong and the bit blunts on the first hole. Read more...
Drill Bit Size Chart — Metric, Imperial, Number and Letter Conversions
Full drill bit size chart converting metric, fractional inch, number (#1 to #80) and letter (A to Z) drill sizes, with exact decimal and millimetre equivalents. Multiply inches by 25.4 to get millimetres. Read more...
Tap Drill Size Chart (Metric) — What Drill Bit for Every Tap
The tap drill size for a metric coarse thread is the thread diameter minus the pitch — an M8 x 1.25 tap needs a 6.8mm drill. Full metric coarse, metric fine and ISO 273 clearance hole charts, plus which drill bit to actually use. Read more...