A Brief Overview of Spot Drills
Spot drills are little pieces of milling equipment that are often overlooked, yet they are essential in any machine shop. These small cutting tools are necessary for drilling holes with exceptional precision, which is a difficult operation when milling.
Spot drills are small drill bits with only a drill point and few or no flutes beyond that point. They are significantly more stable than longer twist bits due to their incredibly low length. Instead of drilling holes, these tools are meant to start drilling to generate a cone-shaped indentation on the workpiece's surface.
The tendency for drill bits to deflect off of hard objects is what makes drilling such a risky machining operation. Drill bits are long in comparison to other milling cutters, and this length has disadvantages. Long tools, particularly those made of steel alloys like high-speed steel, will wobble naturally as they spin. This can cause them to miss the correct angle for striking a workpiece's surface, deflecting the drill bit's point and ruining the cut.
This might cause major issues because milling is normally an extremely precise machining operation. Because end mills and other cutting tools have a higher width to length ratio, this issue is virtually exclusively limited to jobber length drill bits with a lengthy flute length. Due to their increased stiffness, carbide drill bits can assist to mitigate this issue, but spot drills are another excellent option to achieve accurate results.
This depression in the material aids in the marking of the hole that you wish to drill with your larger twist bit. The point of your longer bit will be guided into the dimple generated by the spot drill, rather than bouncing or deflecting off of the surface. The spotting method will improve the accuracy of your holes significantly, which can be extremely crucial for some parts.
You should think about a few things regarding your gear when spotting to achieve the greatest results. You can still risk the bit deflecting on contact if the point angle of your spot drill is not equal to or greater than that of your longer bit. When operators utilize a center drill instead of a spot drill, this is a regular problem. You should also think about the materials used in your tools. When drilling with steel drill bits, spotting is recommended, although it may not be essential when drilling with carbide drill bits, especially those with shorter lengths.
Check out Online Carbide if you need some spot drills or carbide drill bits for your milling machine. They are a solid carbide cutting tool company based in the United States. Manufacturer direct prices on goods such as jobber drills, stub drills, spot drills, drill mills, and many types of end mills may be found at www.onlinecarbide.com. If you have any queries about Online Carbide's tools, you can contact a member of their staff by sending an email to sales@onlinecarbide.com.
