When To Use Spot Drills, Stub Drills, and Jobber Drills For MillingPosted by johnhrq on December 7th, 2020 Milling machines are designed to use special cutting tools to quickly and accurately remove material from a workpiece. There are a wide range of tools that can be used to mill various materials, but some tasks are a little bit more complicated than side milling operations. Drilling is one deceptively simple task that often requires special considerations from machine operators. Drilling an accurate hole normally takes some combination of spot drills, stub length drills, and jobber length drills. Drilling is so complicated because drill bits are not the most accurate tools. Because drill bits are long and they rotate at high speeds, they tend to oscillate much more than other cutting tools. This means that drill bits can easily “walk” off their mark when they contact a surface that is hard enough to deflect the bit. Using the proper tools can help users avoid this issue and get clean holes every time they need to drill into a workpiece. Spot Drills The dimples created by these tools will help larger twist drill bits seat themselves accurately and decrease the likelihood of your twist bit walking off its mark. One important fact to consider when spotting is the point angle. The angle of the spot drill’s tip should be larger than the angle of the twist bit’s drill point in order to ensure that the twist bit contacts the bottom of the spot dimple before the side. Stub Drills Jobber Drills If you need drill bits for your shop, there are a lot of options to choose from. Some of the best high speed cutting tools are constructed from carbide, a metal and ceramic composite material. Tools made from carbide are more rigid and heat resistant than high speed steel alloys. One great American manufacturer of solid carbide drill bits and milling cutters is Online Carbide. You can see their complete inventory of products, including spot drills, stub drills, and jobber drills, when you visit their online store at www.onlinecarbide.com. For more information about Buy Carbide Drills and Drill Mills Please visit : Online Carbide. Like it? Share it!More by this author |