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3 Piece Large HSS Spiral Step Cone Drill Set | 4-12/20/32mm


  1. One piece of 15-step drill bit for 15 different holes: 4 / 6 / 8 / 10 / 12 / 14 / 16 / 18 / 20 / 22 / 24 / 26 / 28 / 30 / 32 mm
  2. One piece of 9-step drill bit for 9 different holes: 4 / 6 / 8 / 10 / 12 / 14 / 16 / 18 / 20 mm
  3. One piece of 9-step drill bit for 9 different holes: 4 / 5 / 6 / 7 / 8 / 9 / 10 / 11 / 12 mm

Suitable For:

  • Steel
  • Brass
  • Aluminium
  • Wood
  • Plastic

About this item

  • Spiral flute for efficient chip removal

Designed for machine and hand drillng tough materials such as stainless steel. Heat abrasion & heat resistance allows drills to retain strength and hardness at higher temperatures.


  • Conical bit with a stairstep profile to be used for drilling 19 hole sizes ranging from 4-32mm, to replace 19 individual drill bits. Self-starting, no need of center punch.
  • Made of high quality HSS (high-speed steel) 4241 and coated with Titanium for prolonged life.
  • Commonly used on sheet metal and in general construction. One drill bit can drill the entire range of holes necessary on a countertop, speeding up installation of fixtures.
  • Ideal for use in electrical work where thin steel, aluminum or plastic boxes and chassis are encountered. The short length of the unibit and ability to vary the diameter of the finished hole is an advantage in chassis or front panel work. The finished hole can often be made quite smooth and burr-free, especially in plastic.
  • Automatically deburrs holes left by other bits, as the sharp increase to the next step size allows the cutting edge to scrape burrs off the entry surface of the workpiece. Save you time and effort.
  • Step drill bit, also known as ladder drill bit or unibit, is a roughly conical bit with a stairstep profile.
  • Due to its design, a single bit can be used for drilling a wide range of hole sizes.
  • The larger-size bits have blunt tips and are used for hole enlarging.
  • The bits come to a point and are thus self-starting. No need to use center punch.
  • They are more durable and not easily broken compared with the ordinary twist drill bits.
  • These high-speed step drill bits feature a titanium coating so they run cool and are made out of high speed steel for a long service life.
  • The drill bits automatically deburr holes as you drill and the two-flute design provides faster, smoother cutting.
  • Whether drilling in plastic, metal or wood, these drill bits cut great every time.

Key Features:

  1. Cool-running titanium coating lasts longer than uncoated bits
  2. High speed steel for longer life
  3. Automatically deburrs holes while drilling
  4. Two-flute design gives you faster, smoother cutting


  • Material: High Speed Steel 4241 (Used for the hardness of the material which is below 25°, like iron board, steel board, PVC board, Insulation board, etc.)
  • Surface: Titanium Plated
  • Groove Type: Spiral Groove
  • For Drilling in: thin iron plate, aluminum, insulation panels, PVC panels 4mm thickness within the timber