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Different Types of Drill Bit Materials

It is sometimes critical that the “drill bit” you choose is the proper type for the job.  You can often use a higher quality tool for a lower difficulty job, but doing the opposite can lead to tool failure, ruined parts or even personal injury or worse.

A softer drill tool can dull more quickly. When picking the type of “drill bit” you need, consider the surface to be drilled into. Some products that can be drilled with automatic drill machines might be:

  • Different types of wood (soft, hard, abrasive like Ipe, etc.)
  • Plastics (HDPE, Phenolic, PVC, etc.)
  • Fiberglass (Or fiberglass impregnated materials)
  • All types of Metal
  • Stone (how do you think they make holes in counter tops for faucets, etc?

Also consider the mass and steadiness or stability of the drill itself. A very brittle bit such as carbide on a small, lightweight drill can actually dull prematurely because of the micro-vibrations caused by a poor mounting system, a lack of total mass, etc.

Materials Drills Are Often Made Of:

Low Carbon Steel Drill Bits: This is the cheapest (or more properly the least expensive) drill tooling generally available. Best used only on soft woods, some plastics, etc. Low Carbon Steel bits need to be sharpened more often and have no place in a reputable shop.

High Carbon Steel Drill Bits: These are better than Low Carbon Steel tooling. They can often be used on hardwood and even some very soft metals. Typically, they have no place in a shop that calls itself professional.

High Speed Steel Drill Bits (HSS Drill Bits): These have essentially replaced the older Carbon steel bits on the market. HSS is much more resistant to heat and wear. They are the most common type found at a supply shop serving professionals such as McMaster-Carr or MSC Direct, etc. These bits are suitable for most wood and metal jobs. There are exceptions such as Ipe which is a wood with very hard particles inside it. It will dull HSS very quickly even though it drills easily.

Titanium Coated Drill Bits (TiN, TiAN, TiCN, more…): Titanium coating makes these bits harder and last longer than the common HSS bits. That is because the coating is a hard ceramic material. If you are having problems with excessive heat build-up or dulling of HSS tooling, you can try this type if drill to solve the problem. For production drilling, using this type of tool allows you to run at a faster RPM and thus lower your cycle time.

There are a number of different Titanium coatings.  The most common are Titanium Nitride (TiN), Titanium Aluminum Nitride (TiAN) and Titanium Carbon Nitride (TiCN). TiN can increases the life of a drill bit by three or more times. TiAN is considered even better, and can increase the lifespan five times or more. TiCN is also considered superior to TiN.

The challenge with coated bits is that once dulled, they can’t be properly sharpened. The coating will be gone. So will all the benefits of the coating. They generally revert to being HSS tooling at that point.

Cobalt Drill Bits: Cobalt bits retain hardness at much higher temperatures than HSS ones. However, they are also more brittle. Cobalt “drill bits” are most commonly used for drilling stainless steel and other difficult metals as well as when you need to run at a significantly higher RPM to save time or when coolant is not available because of a part that needs to be painted in the very next step, etc.

Carbide Tipped Drill Bits: These are very hard, dissipate heat quickly and hold an edge longer than other types. However, Carbide tipped bits are also brittle and are likely to chip if not used carefully. For instance, some carbide bits work well on a multi-thousand pound drill press or milling machine such as the Bridgeport but do not work well in an AutoDrill or other selffeeder drill unit. There simply isn’t enough mass to protest the tooling from vibration. AutoDrill suggests testing the tooling out on a standard drill press prior to buying a large batch for use on a self-feeding drill machine.

Carbide tools are often used in fiberglass reinforced plastic drilling processes as they hold up to the abrasive nature of Fiberglass Drilling much better. Some customers use diamond for even better results.  See the next entry for diamond drill tool information.

Diamond Drill Bits: Polycrystalline diamond (PCD) is one of the hardest tool materials available to the average person. It actually consists of a layer of diamond particles bonded to a carbide support in most cases. Since diamond is the hardest thing found in our environment that we know of, the diamond bits can be used on the toughest materials.

Diamond is carbon. Carbon is flammable.  Keep those diamond tools cool!  They WILL be ruined by heat.

Diamond drills are generally used to grind away material on a micro level. They are the favorite tool of masons trying to drill precision holes in stone, concrete, tile, glass, etc. With that in mind, Diamond “drill bits” can be used on glass, porcelain, ceramic tiles, granite, marble, stone, fiberglass, etc.

They are also commonly used in the automotive and aerospace industries. Basically in any environment where abrasive materials need to be drilled.

AutoDrill suggests that you speak to a reputable tooling distributor before making any important tooling purchases. If you are drilling a few holes here or there, then a standard drill set will likely meet your needs. If you are drilling a million holes a year like some of AutoDrill’s customers do, tooling choices become much more important. Do it right the first time no matter how much of a rush you are in because you will always find the time to do it right the second time.

Please CONTACT US to discuss your application and receive prompt product cost, literature and technical help.

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