Are you buying drills or holes?

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I was recently asked what type of drill someone should use when drilling nonferrous materials. There’s not just one answer for this type of question. There are, however, holes that may require different types of drills.

One type may be a clearance or bolt hole. In this case, I’d suggest using the least expensive drill that’ll provide you with the necessary features. In these cases, you won’t need to bore or ream the hole.

In other situations, you might need to create a hole that has a tighter tolerance. In this operation, you’ll need to decide on reaming or boring to finish the hole and provide the desired tolerance. You must also make sure that ovality and straightness requirements are met.

Through the years I’ve found straight flute solid carbide drills are a very good choice to create holes with tighter tolerances. There are several manufacturers of these tools. These drills provide the stability of solid carbide and also provide features that create one-pass drilling, eliminating the need for boring or reaming.

Solid straight-flute drills come in several styles and types. Some of them provide burnishing capabilities that allow sizing of the hole, eliminating the need for additional work. Other drills also have drilling and reaming capabilities built into the same tool, and most of these tools burnish as well. Many of the straight-flute drills don’t require center drills, which also helps to eliminate additional operations.

Almost all the tools I’ve worked with come with thru-coolant, which is an additional plus. So, if these tools are so great why aren’t they more widely used? I’ll tell you that I sold these types of tools for many years and the main push back is cost! We’ve become accustomed to the price of high-speed steel drills and try to compare that cost to a one-shot solid carbide tool.

To make sure you buy the right tooling you need to ask, “Am I buying a drill or a hole?” This may seem like a ridiculous question, however it’s a very important one. If all you need is a bolt hole or a clearance hole, then by all means buy a drill. But in my experience, many of you need to buy a hole! In this situation you don’t compare a hole price to a drill price. There’s no comparison. In all cases buy the hole when it’s necessary.

Work with your preferred tooling supplier. They can always help you get the correct tooling or hole you require.

CMR Consulting

miker2468@aol.com

Mike Ramsey, president of CMR Consultants, retired from Kennametal Inc. as vice president, global machine tool industry sales, after 39 years of service in sales and marketing. He can be reached at miker2468@aol.com.

November December 2022
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