Spade Drill Bit Sets

Spade Drill Bit Sets for Australian Joinery and Construction

Spade drill bits (also called paddle bits or flat bits) are flat-pattern wood-cutting bits with a centre point and two cutting edges spread on a flat blade. They drill clean, fast holes in timber and wood-based materials at significantly higher speed than twist drills, and are the everyday choice for plumbing, electrical, and joinery work where speed matters more than finish quality. AIMS Industrial supplies spade drill bits and sets in the metric and imperial sizes Australian trade users actually need.

How spade bits work

The flat blade has a centre point that pulls the bit into the work and prevents wandering, with two cutting edges that scrape rather than chip the wood. The geometry suits high-speed drilling — typical speeds 1500-2000 RPM for general timber. The result is a fast clean hole with reasonable centre accuracy, but with rougher entry and exit edges than twist drills produce.

Where spade bits earn their place

• Electrical wiring runs — drilling holes through studs and joists for cable runs
• Plumbing penetrations — fast holes for pipework through framing
• HVAC ductwork — through-frame holes for duct and refrigeration lines
• General carpentry and joinery — fast drilling for fittings, dowels, and structural connections
• Site work where finish matters less than speed — rough drilling for fixings and accessories

Sizing — common diameters

Spade bits are stocked in metric and imperial sizes. Common metric sizes range from 6mm through 38mm; imperial sizes range from 1/4 inch through 1-1/2 inch. Larger spade bits (over 25mm) need a powerful drill — undersized drills bog down on the larger bits, particularly in hardwood. For the largest holes, hole saws or auger bits are usually faster than spade bits.

Set configurations

Spade bit sets typically cover 6-8 sizes in a hard case — common ranges include 6mm-25mm metric or 1/4 inch to 1 inch imperial. For most trade users, a basic 8-piece set covers daily work; specialty sizes are added as singles for specific requirements.

Spade bits versus twist drills versus auger bits

• Spade bits — fastest in timber, rough finish, low cost; good for through-holes where finish doesn't matter
• Twist drills (HSS) — slower in timber, cleaner finish, work in metal too; good for finish-critical holes
• Auger bits — clean finish in timber, faster than twist drills, screw-pattern feed; good for deep holes
• Forstner bits — flat-bottomed holes, finest finish, slow; for fine joinery work

For trade timber drilling, spade bits are the fastest tool. For finish work, twist drills or Forstner bits give better results.

Drilling practice

Run the drill at high speed (1500-2000 RPM is typical for spade bits in general timber). Apply firm but moderate pressure — the centre point pulls the bit into the work, so excessive force just bogs the drill down. For deep holes, withdraw the bit periodically to clear chips. For exit splintering on the back face, drill until the centre point breaks through, flip the workpiece, and finish from the back.

Brands stocked at AIMS

Sutton Tools, Bordo, and approved trade brands cover the spade bit range. The build quality of spade bits matters less than for twist drills — the spade pattern is forgiving — but quality bits hold their cutting edge longer and produce cleaner holes than budget alternatives.

Companion ranges at AIMS

Spade drill bits sit alongside our broader drill bit range — see multi-purpose drill bits, spotting drill bit sets, reduced shank drill bits, and holemaking tools for the related products.

Need help speccing spade bits for trade or carpentry work? contact our team — we'll match size range and brand to your work.