Drills and drill bits are essential gear for any toolbox. They’re one of the first pieces you’ll be grabbing when there’s a need to get holes in the right width and depth. The task can get tricky if you’re dealing with holes of different sizes, as you’ll be changing more than a few bits for the same project. This not only takes more time but can become a hassle to the point that precision is put on the line. You’ll also need quite a few drill bits, all in top condition to complete the job.
An easier way out is getting the appropriate step drill. This swaps out a whole set of bits without compromising usability. You’ll still be able to drill holes of varied sizes, but all this comes in a compact package that takes up less toolbox space and saves you money too. And they’re used with the same essential workshop gear such as handheld or bench drills, and without the need for any additional equipment.
What are Step Drill Bits?
Step drill bits are conical in shape, with pointed tips, sharp cutting flutes, and ‘steps’ that gradually increase in width from the tip to the shank. The design allows drilling holes in multiple sizes, from pilot holes to larger holes of any size with much more precision. Like other drill bits, step drills come in different sizes, with widths laser engraved on each step. They can also be sourced from metals and alloys of varying hardness and in different cutting profiles.
Design Specifics
The bits have been described in interesting ways, from Christmas trees to inverted ice cream cones. They have sharp pointed tips set at an angle that does the initial piercing into the material you’re drilling. These are in one of three angles (118°, 130° and 135°), then extend into two sets of cutting edges all the way to the last step, and terminate with the shank.
Steps are set at 90 degrees of each other and help in chamfering or deburring existing holes. Step counts also differ. Most bits have 9 individual steps, effectively replacing up to 9 separate twist drills. Some go even further, with 15 steps. Shanks are of the 3-flat type, that grip the tool chuck and prevent slippage.
According to how the cutting flutes are placed, step drills are of two basic types- straight and spiralled. The channels in the flutes get rid of material as it is drilled and also prevent the bit from heating up. Spiralled drill bits are generally faster at removing excess material and keep cooler as a result, meaning extended work times.
Materials They’re Made Of
Most step drill bits are made of HSS, and the same material is used across a wide range of drills. This has good wear resistance and is regarded as a general-purpose drill bit equally effective in materials ranging from harder ferrous metals to softer plastics. Step up to cobalt bits if you require more speed and depth precision in thicker metal sheets, or choose titanium or carbide-tipped bits for especially hard materials like masonry or cast iron. These should also hold sharper edges for longer, so you’ll be carrying out more work too.
How Step Drills Are Used
Using step drill bits is like any other bit type. They easily fit chucks of corded and cordless drills and drill presses. And offer more precision in getting holes to the desired depth and width. Drilled holes are also cleaner, as flutes do a great job of removing excess materials and clearing away burrs.
Since widths are visibly marked on each step, you’ll know exactly the width and the drilled depth of the hole. This is important for further fabrication or when adding fasteners in specified sizes. The bits are most effective at low to medium RPMs. When drilling, you’ll want periodic breaks to check on hole depth and prevent overheating.
Applications and Benefits They Offer
There’s a long list of reasons to choose a step drill. This gets clean, precise and accurate holes, especially in sheet metals. The bits can be used down to depths of 1.5mm in ferrous metals and 6mm in thermoplastics, such as acrylic and plastic sheets. Moreover, they work equally well in thinner wood pieces.
A single bit also speeds up the whole process. You can create pilot holes, drill to desired depths, bore out larger holes and clear burrs and imperfections all with the same tool. Chamfering is another benefit and often overlooked use.
The additional benefits are the finishes that you won’t get with any other drill bit. Moreover, the bits are less likely to slip, or cause surface damage or cracking in the drilled material. The tools are especially popular with electricians when drilling holes to accommodate fixings of different sizes, and when installing junction boxes, panels and more. Plumbing is another industry where step bits show their worth. They’re also used in the automotive industry, specifically with body panels and routing wiring and electrical components. HVAC technicians use them too, as here there’s often the need for holes of different sizes when setting ducting and equipment.
