Buy Combined Drill Countersinks Online in Australia
Combined Drill + Countersink Selection — Quick Reference
Combined drill + countersinks (centre drills) produce PILOT DRILL HOLE + 60° COUNTERSINK in single operation. Standard toolroom + machine shop tooling — wherever concentric + accurately positioned centre location is required.
| Centre Drill Type | Best For | Common Sizes |
|---|---|---|
| Type A (Standard Plain) | General workshop centre + spotting — workshop default | #0 / #1 / #2 / #3 / #4 / #5 |
| Type B (Bell-Mouth) | Higher-load centre — between-centres lathe work | Same size range — stronger pilot |
| Type R (Radius) | Radius at junction — eliminates stress raiser | Premium — bearing + precision work |
| HSS Standard | Mild + alloy steel + general workshop | Sutton + P&N + Bordo |
| HSS Cobalt (M35/M42) | Stainless + tough alloys | Higher hardness |
| 60° Included Angle (Standard) | Standard lathe centring + drilling lead-in | Most common |
| 90° Included Angle | Specific applications — match workpiece | Less common |
| Set (Multi-Size Pack) | Workshop assortment — #0-#5 range | Toolroom standard kit |
Critical: Match centre drill size to workpiece — too small = breaks easily under pressure; too large = oversized centre + reduced live-centre support. Use cutting fluid + low-medium speed. Workpiece spotting mandatory before twist drill — centres + prevents wandering on inclined or rounded surfaces. Brands: Sutton, P&N. Companion: centre drill bit sets, drilling, centre punches, countersink bit sets.
Combined Drill Countersinks
AIMS Industrial stocks combined drill countersinks (centre drills) from Sutton and P&N in HSS and cobalt grades — precision tools that produce a pilot drill hole and 60-degree countersink in a single operation. Combined drill countersinks are standard toolroom and machine shop tooling, used wherever a concentric, accurately positioned centre location is required before further machining.
Why Combined Drill Countersinks?
The short, stiff body of a combined drill countersink resists deflection at start-up — unlike a long twist drill, which will wander from a centre-punch mark before the cutting edges engage fully. By drilling the centre location and producing the countersink in one tool, the pilot bore and the countersink are guaranteed to be concentric. Using separate tools for the pilot drill and countersink introduces the risk of misalignment between the two operations, particularly on older machines or where workpiece fixturing is not perfectly rigid.
Series and Sizes
Combined drill countersinks are available in three standard series, each suited to different spindle and component sizes. Series 1 is the compact form for small lathe work, with pilot drill diameters from 1mm to 3mm and a correspondingly small countersink cone — used on small-diameter turned components and instrument work. Series 2 is the general workshop and production series, covering pilot drill diameters from 2mm to 5mm, and is the most widely used size across manual lathes and drill presses. Series 3 is the heavy-duty form for larger spindles and components, with pilot drill diameters from 3mm to 8mm and a larger countersink cone for deeper, larger-diameter centre holes.
HSS vs Cobalt
HSS combined drill countersinks suit manual lathe and drill press work at standard cutting speeds. Cobalt HSS grades provide better heat resistance for CNC operation, automated spindles and harder workpiece materials where higher spindle speeds are used. The cobalt grade is the correct choice for production centre drilling on CNC lathes and machining centres where tool life between changes is a priority.
Applications
Lathe centre drilling for between-centres work, spindle bore preparation, countersunk screw hole preparation in a single pass, and drill spotting on curved or inclined surfaces are the primary applications. In production turning, every part that is machined between centres starts with a combined drill countersink operation — it is the first cut on the part and the reference on which all subsequent operations depend, making tool quality and dimensional consistency directly relevant to the accuracy of the finished component. In fabrication and maintenance environments, combined drill countersinks are used to start holes on curved surfaces and angled cuts where a long drill would deflect. AIMS stocks Sutton and P&N combined drill countersinks in HSS and cobalt across Series 1, 2 and 3. For help selecting the right series and grade for your lathe or machine, contact our team. AIMS Industrial has been supporting Australian workshops since 1988.