While machinists are familiar with spot drills and center drills, the same can't always be said of your everyman and husband looking to either do a fix on some part of the house, or assemble or build a piece of furniture.
That said, it's not that difficult to familiarize yourself with some of the tools and technical terms that machinists are familiar with. In this case, it's the difference between spot drills and center drills.
What Is Spot Drilling?
Spot drilling is the task of making sure that the hole to be drilled is accurately located. Spot drills are often designed to be extremely rigid to avoid what is called drill walking, or those instances when the drills strays from the exact location you're trying to place the hole in.
The purpose of spot drilling, then, is precision. After all, drilling a precise hole can be difficult, especially against hard and slippery surfaces. Spot drilling is performed to create a small divot or dimple to avoid drill walking once you start deep-hole drilling.
How is Center Drilling Different from Spot Drilling?
While there are those that may confuse spot drilling and center drilling and end up using them interchangeably, the two aren't the same. They involve different procedures, and performing one operation in place of the other can potentially damage your tools.
Compared to the spot drill, which is thin and has a short regular twist drill bit, the center drill is composed of two parts: the small pilot, or the narrow, cone shaped end, followed by the larger and wider countersinking area.
The purpose of a center drill is to create a place or a seat for a lathe center, whereas the purpose of a spot drill is to create a starting point for the sake of precision.
When To Choose Between A Spot Drill And A Center Drill
In terms of the material that you're going to be drilling holes into, a center drill is usually considered the better choice for denser metals.
Spot drills are better suited, on the other hand, for softer metals, plastics, and wood due to the fact that they're designed for greater accuracy. Their thin make is also suitable for drilling around tight areas, and is a better option for effectively creating a hole without damaging the material by splitting or breaking it.
Advantages and Disadvantages of Center Drills
Center drills are more cheaply available compared to spot drills. They're suited for metals because of their shorter and sturdier design, which allows them to stay on target more often during drilling.
One thing to consider though, is that the small pilot tip of a center drill can be delicate, and can potentially break. Another thing to consider is the center drill's angle, which is usually narrower than a spot drill's angle.
If your goal is to create an accurate hole, you want the broader angle of a spot drill. This broader angle means that the tips of the twist drill makes contact with the spot hole first, and doesn't hit against the outside diameter of the divot or dimple.
Get Started Spot Drilling
Hopefully this clears up the difference between spot drills and center drills. It's important to know the difference, especially when you're shopping for tools and drill bits. After all, you need the proper tools and materials if you want to do a proper job.
Finding and acquiring spot drills or other carbide round tools can be difficult and sometimes even costly, especially if you're buying from resellers. If you want to go straight to a manufacturer and get your tools and materials at prices usually offered to distributors, we recommend checking out Online Carbide.