7 Pieces Center Drill Bits Set, M2 High Speed Steel 60-Degree Angle Center Drill Bits Kit Countersink Tools for Lathe Metalworking Size 1.0 1.5 2.0

A center drill bit is a very useful pieced of kit if you are doing any metal working.
They are incredibly accurate, solid and useful.
60-degree angle plain center drill bits are used for drilling precise center holes with diameters range from 1mm to 5mm.
They also can give you an extremely good starter holes and you can drill up with the correct size drill bit and then tap it.

Tips in using center drill bits：
1. Fix the work piece deep in the Lathe machine to prevent wobbling when rotate
2. Get rid of acid surface before drilling and use oil or proper lubricant to protect the bits
3. A good rule to follow is to go 2/3 deep on the tapered section
4. Stop immediately if the drilling sound is abnormal and fix any problem before resuming
5. Clean the center drill bits before and after drilling, and apply oil to store it properly

They come in different sizes including Number 1.0 1.5 2.0 2.5 3.0 4.0 5.0 and stored in a solid storage case.
Number 1 and Number 4 are the two most common sizes