...I also agree with the advice on not using a center drill for starting drilling operations.
Like Wreck said, center drills are designed for making 60 degree holes for lathe centers to fit into. The 60 degree taper is also not a good choice for any following drill with a larger point angle because the drill will walk around as it catches on the 60 degree hole edges. Further, it is easy to break off the point of a center drill while drilling in harder materials, often ruining the part while trying to get the broken point out of the hole.Why not, as long as it provides a coaxial starting hole?
...The 60 degree taper is also not a good choice for any following drill with a larger point angle because the drill will walk around as it catches on the 60 degree hole edges. Further, it is easy to break off the point of a center drill while drilling in harder materials, often ruining the part while trying to get the broken point out of the hole.
Like Wreck said, center drills are designed for making 60 degree holes for lathe centers to fit into. The 60 degree taper is also not a good choice for any following drill ...
Using the 120 degree point of the center drill to spot a hole works fine for a 118 degree drill to follow, I do that sometimes. Needs to be a larger center drill for more than tiny holes to follow. If the center drill is used deeper than just the tip, it leaves a cylindrical hole that can be difficult for the main drill to follow.Thanks Bob. You don't need to use the 60* portion--just the center drill portion. I've been using this in 316 stainless without a problem because I don't have a set of spotting drills yet.