A Practical Guide to Drill Bits

Posted by cjs727 on Nov 1st, 2011 | 12 comments

When starting a project that requires drilling you should first make sure that you are using the right type of drill bit. If you use the wrong type you could damage the material you are working on. You can determine which drill bit to use based on what material you will be drilling into. Here is a practical and basic guide about drill bits and which are best suited for some of the more commonly used materials used in DIY projects.

Metal

When drilling into a non-ferrous metal, you will need to use High Speed Steel (HSS) drill bits that are made with partially ground tips. Non-ferrous metals include: aluminum, copper, zinc, brass and non-alloyed steel. If drilling into stainless steel, a different type of drill bit should be used. For this material, drill bits made of cobalt-alloyed High Speed Steel (HSS-E) or drill bits which have a titanium coating are best. They are more expensive than regular HSS drill bits but they allow for drilling without having to worry about excessive wear to the bits themselves.

Wood

When drilling into wood, brad point bits are best. Brad point drill bits have a long centering tip with two pre-cutting spurs. These spurs are used to score the wood fibers before the internal cutting edges cut them out cleanly.  Forstner drill bits, hardware drill bits or hinge cutting bits are usually used for larger diameters and there are auger bits for boring deep holes into wood.

Masonry

Drilling into brick or concrete will require the use of an impact drill or rotary hammer. If you are drilling any such material that contains perforated stones with a porous material, only rotary drilling should be preformed (without impact). This also applies when drilling into porous bricks and boarded walls. In order to drill into these materials, you will need a masonry drill bit. Masonry drill bits have tungsten-carbide tips designed to give the strength needed to penetrate the hard material and used with a rotary drill to lessen the likelihood of cracking and splitting that would happen with an impact drill.

If you are not sure which drill bit to use, don’t guess because this could have negative results. Ask someone who is knowledgeable, either by way of experience in the use of drills or those trained in the sale of such tools. Those who work at hardware stores usually have the knowledge needed and will be able to assist you with which bit is best for each type of job and material you will be working with.