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Drill Bits Buyer’s Guide

Drill bits are used to make different sized holes in various types of materials, so it's important to know which bit is best for your project. Using the wrong bit can not only damage the substrate and tool itself, but it can also lead to injury. It's important to understand which drill bits you need for your project before making a purchase.

Understanding Drill Bits

For starters, the shank is the bit's end that stays secured in your drill's chuck. There are three basic types of shanks.

The shank is connected to the drill bit's shaft and ends at the point. When deciding on a bit, remember that flatter points are better for harder materials and may require a pilot hole to get started. It's also important to know that a drill bit's size refers to the diameter of its body, but most bit sets have the sizes commonly needed for most jobs.

Drill Bit Materials

The material that a drill bit is made out of determines its lifespan and degree of functionality, so make sure that the one you're using is suitable for the material that you're drilling into. Here are some common drill bit materials and the types of jobs they're good for.

High speed steel (HSS) drill bits consist of strong tool steel, which makes them inexpensive and very common. These highly versatile bits are great for:

  • Softwoods
  • Soft metals
  • Polyvinyl chloride (PVC)
  • Fiberglass

Black oxide-coated HSS bits resist rust and corrosion better than HSS bits, and they're 50% more durable. Use these bits for:

  • Metals
  • Hardwoods
  • PVC
  • Fiberglass

Cobalt drill bits are made of a hardened steel alloy that quickly dissipates heat. Since the friction from drilling into hard metals creates so much heat, these bits are the ideal choice for:

  • Cast iron
  • Titanium
  • Stainless steel

Titanium-coated bits are sharp and harder than cobalt bits. They also dissipate heat even more quickly than cobalt bits and are the best choice for general production work. The tip must be recoated with titanium nitride (TiN) when it becomes dull, but it's usually cheaper to just replace the bit. Titanium nitride-coated bits are suitable for most:

  • Woods
  • Plastics
  • Metals

Carbide-tipped drill bits are very tough and only suitable for specialty jobs that require drilling into extremely hard materials. Therefore, they should not be used in most hand-drills and drill-presses. The most common applications include:

  • Masonry
  • Tile

Drill Bit Types

Drill Bit Maintenance

Making sure you're using the right drill bit for the job is the best way to ensure the life of these tools, but there are a few other things that you can do to take care of them:

  1. Let the bit cool down after drilling
  2. Clean the bit and brush away any swarf
  3. Apply a small amount of machine oil periodically
  4. Regularly inspect the bit for damage
  5. Keep bits' points sharp (or replace dull bits)
  6. Store bits in a cool, dry place
  7. Store bits in plastic sleeves (or a specific case) to prevent abrasion from other tools

Always make sure you're using the right drill bit for the job and consider using depth stops, bit holders and drill extensions to make things easier. Finding the right bit to use takes a little bit of study (and perhaps trial and error), but once you know your bits, projects become much easier.

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