Micro Drill Bits

Micro Drill Bit Selection — Quick Reference

Micro drill bits cover the SMALL end of drilling — typically below 3mm down to 0.3mm or smaller. Thin material + fragile workpieces + tight tolerances rule out standard jobber drill. Used by toolmakers + electronics + model engineers + precision workshop.

Critical: Micro drills are FRAGILE — drill press / mill spindle mandatory (NEVER hand drill); use centre punch + pilot location; appropriate RPM (small dia = HIGHER RPM, can reach 5,000-20,000 RPM); cutting fluid mandatory; gentle feed. NEVER force — broken micro drills in workpiece are very difficult to extract. Brands: Sutton Tools, Bordo. Companion: drilling, cobalt drill bits, centre drill bit sets.

Micro Drill Bits

Micro drill bits cover the small end of the drilling range — typically below 3mm and down to 0.3mm or smaller — where thin material, fragile workpieces, or tight tolerances rule out a standard jobber drill. AIMS Industrial stocks micro drills in HSS and solid carbide for toolmakers, electronics technicians, model engineers, and precision workshop applications.

Where micro drills earn their keep

• PCB and electronics work — through-hole component lead holes and via drilling
• Jewellery and watchmaking — fine-detail piercing and assembly
• Toolmaking and die work — coolant holes, ejector pin clearance, and venting
• Model engineering — locomotive boilers, valve gear, and detail fastenings
• Repair and modification — drilling out broken micro fasteners and pins

HSS or carbide?

HSS micro drills are the everyday choice — flexible, forgiving of speed and feed errors, and economical in the smaller sizes where breakage is just part of the work. Solid carbide micro drills hold a finer edge and run truer at speed, but they're stiff and brittle — perfect on a CNC at correct RPM, less forgiving on a bench drill.

Sizes and sets

Common metric ranges include 0.3mm to 1.0mm in 0.05mm or 0.1mm steps, and 1.0mm to 3.0mm in 0.1mm steps. Imperial number drills (#80 to #1) and letter drills are stocked alongside metric. Sets are popular for toolrooms; singles for replacement of broken bits in known sizes.

Brands and quality

The range includes Sutton Tools, Bordo, and Champion in HSS, and selected carbide brands for precision applications. Coatings such as TiN and TiAlN are available where extra tool life is needed.

Drilling practice for tiny bits

Run higher RPM (small-diameter drills need surface speed, not spindle speed), use a peck-drilling cycle to break the chip, and clamp the work square — even a small misalignment shears the bit at the shank. Centre-drill or spot-drill first if the surface is anything but perfectly flat.

Pilot holes and centring

A 0.5mm drill won't find its own centre on a hard, smooth surface — it skates and breaks. Centre-drill or spot-drill the location first using a small centre drill or a spotting drill with a stiff shank. Once the cone is established, the micro drill follows it cleanly. For PCB and electronics work, the same principle applies — scribe or centre-punch the location before reaching for the small drill.

Sets versus singles

Toolrooms typically run a numbered metric or imperial set in a wood case so a missing size is obvious at a glance. Production users often skip the set and order singles in the sizes they break — usually the smaller end of the range. Both approaches work; the case matters as much as the bits, since a loose 0.5mm drill at the bottom of a toolbox is a lost drill.

Need help with a tricky size?

contact our team — we can source non-standard metric sizes and bulk pack on the common ones.