When it comes to using a milling machine, producing accurate holes can be a real challenge. Drill bits are not the most stable tools, which can lead to your bits “walking” off their mark and potentially ruining your workpiece. If you have experienced these issues with your milling machine, then spot drills and carbide bits might be the solution to your drilling problems.
Drill bits are moderately unstable tools compared to end mills. This is because they are long relative to their diameter. When operating at high speeds, they naturally oscillate. This makes it harder for your drill bits to hit the center of the mark for your hole. When it comes to milling, which is an extremely accurate process, even a small deviation caused by an oscillating drill bit can be detrimental to your final product. Luckily there are a number of ways to correct these issues.
One of the first things to consider is the material being used in the construction of your tools. Not all drill bits are created equal and the cheaper steel bits are also going to oscillate more dramatically at high speeds. This is what makes carbide drills so efficient. Because of their ceramic and metal composition, carbide bits are extremely rigid. This rigidity helps to increase the stability of the drill bit and keeps the rotation of the bit far closer to the true center than tools made from steel.
Using spot drills is another way to increase the accuracy of your holes. Spot drills are extremely short bits that are limited to just a cutting point on the surface of the tool. They cut out a cone shaped dimple in the workpiece to mark the location of holes. Because of their short length, they are extremely stable and accurate. The dimple that they produce provides an easy area for longer twist bits to seat themselves, severely limiting the odds of having a bit “walk” off its mark and produce inaccurate results.
If you are drilling with steel drill bits, spotting is probably the best way to ensure accuracy. As long as the point angle of your spot shrill is equal to or larger than the point angle of your drill bit, the bit should be able to find purchase easily. This can be where a lot of machinists make mistakes. Tools like center drills may look similar to spot drills, but they can have smaller point angles and produce dimples that your longer bits can still deflect off of. That’s why it is so important to use the right spot drills or carbide bits when accuracy is crucial in your milling operations.
You can find both solid carbide spot drills and carbide drill bits when you visit www.OnlineCarbide.com. They specialize in offering high quality carbide end mills and drill bits at manufacturer direct prices. If you have any questions about the tools that they offer, feel free to reach out to a member of their team by sending an email to [email protected]