A step drill bit, also called a cone drill bit, drills clean round holes in sheet metal, aluminium, plastic and thin steel in several sizes from one bit,. This collection holds Bosch HSS step drill bits.
Choosing a step drill bit
- Size range. The Bosch HSS Step Drill Bit 4-12mm covers cable glands and small fittings. The Bosch HSS Step Drill Bit 4-20mm reaches the common conduit and switch sizes. The Bosch HSS Step Drill Bit 6-30mm handles large glands and pipe penetrations.
- Material thickness. Each step is only a few millimetres tall, so a step bit suits sheet and thin plate. For thick steel, use a twist drill or hole saw instead.
- Bit material. HSS copes with mild steel, stainless sheet, aluminium and plastics. Use cutting fluid on stainless to keep the edge sharp.
How to use a step drill bit
Centre-punch the hole position so the tip does not wander. Start at low speed and light pressure, letting the first step cut a pilot. Keep the drill square to the surface and feed steadily; each step enlarges the hole and the step before it deburrs the edge. Stop when the marked ring for your size breaks through. Clear the swarf often so the flutes do not clog.
FAQ
Can a step drill bit go through wood
Yes, but it tears the back of the hole. For clean holes in wood use a Forstner or spade bit.
What is a cone drill bit
It is the same tool as a step drill bit. The cone shape is made of stacked steps, each one a standard hole size.
These step drill bits are in stock at our Claremont, Cape Town shop and ship nationwide by courier. Our staff drill panels and enclosures daily and can advise on size. See also Forstner bits and cordless drills.
