Spot Drills and Carbide Tools: The Keys to Drilling Accurate Holes

When it comes to drilling holes with a milling machine, accuracy is everything. This is especially true when manufacturing interlocking components with tight tolerances. Sadly, drill bits are long tools that can be unstable at high rotational speeds. Milling is all about precision, so drill bits can be a big problem. For this reason, using spot drills and carbide tools is essential for machine operators who want to achieve precise results.

What’s the Problem with Drill Bits?
Drill bits are commonplace tools that can often be seen in woodworking. Oftentimes, accurate holes can be drilled in wood using simple hand tools. This is because wood is a flexible and tolerant material, which means that your holes can be slightly off without producing an unusable product. With materials like metal, which does not have the same flexibility, it can be harder to produce accurate results. When holes need to be precisely aligned, the issue becomes even more difficult.

This is a result of the fact that drill bits wobble when they are spinning. This effect is often too subtle to notice with the naked eye, but it can have a serious impact on your tools’ performance. Because the tip of a spinning drill bit is wobbling, it will probably not contact your workpiece with its tip precisely lined up. When drilling into hard materials, this can make your bit “walk” off its mark and misalign your holes. Shorter drill bits are less likely to produce this issue, but often long twist bits and necessary for certain hole depths.

Spot Drills
One of the best ways to drill accurately is to use a spot drill. Spot drills are short cutting tools with a cutting surface that is limited to only the drill point. This short size significantly reduces the drill’s tendency to wobble, making them extremely accurate. Because these cutters are so short, they cannot be used to drill traditional holes. Instead, spot drills are used to mark the location of holes on a workpiece. The conical dimples they produce are designed to give longer drill bits a place to seat themselves, significantly minimizing the risk of having longer twist bits walking off their mark.

Another way to produce accurate holes is to use tools constructed from carbide. Carbide tool stock is a composite material made from tiny granules of tungsten carbide ceramic powder mixed with a binding metal, typically cobalt. The metal provides strength while the carbide itself provides incredible cutting power. The edges on carbide tools will stay sharp longer and they are also more accurate. This is a result of the rigidity of carbide tool stock when compared to high speed steel tools. On some materials, a carbide twist bit should be all you need, though spot drilling is recommended for machine operators who are looking for the best results.

If you have been experiencing difficulty when it comes to drilling holes with your milling machine, then using spot drills and carbide tools is the perfect solution. To find some amazing solid carbide tools, all you have to do is visit As an American manufacturer of drill bits and end mills, Online carbide has stub drills, jobber drills, and spot drills machined from solid micro-grain carbide tool stock. Visit their website to see all of their amazing tools, which are available at manufacturer direct prices. If you have any questions or are interested in having custom carbide drills made for your shop, you can reach out to their team by sending an email to

For more information about Chamfer Mills and Drill Mills Please visit : Online Carbide.

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