Will a Stub drill eliminate the need for a center drill?

[pacifica]

Sizes 3/16 1/4 and 3/8. I doubt the 3/16 will, but will the others?

I did a test between spotting drills( Keo) and split point stubbies- 1/4,3/8 and 1/2. The stubbies were new USA models. After drilling about .1" deep in 6061 alum. I then put layout fluid on the indent and then used a pointed edge finder to make an indentation in the hole. I inspected under 40x with a nikon microscope.

The split point stubbies were off center by .003 to .004. The spotting drills were dead center every time.

 

[Batmanacw]

I only spot drill if the hole location is critical. Stubby split point drills seem to work very well most of the time.

 

[Larry$]

I've got a nice set of screw machine bits that are my go-to for most things. If it is a critical hole, then I use a center drill or spotting drill first.