Spilt Point Drill bit question

Point splitting of the very smallest sizes probably varies with the manufacturer. What it comes down to is the precision of the cut ground on the drill bit and skill of the operator. Below a certain limiting size it becomes impossible to make the "split" without excessive damage to the point.

Also, why would one want a split point on such small drills? I find the web is only a real issue on drill sizes above ~3/16" or 1/4" anyway.

Regards,

Robin

Mine transitions between #52 and #53. It is an index of cobalt screw-machine length bits.

I had not thought to check before your posting -- and I had to dig out the 10X jeweler's loupe to be sure.

But I believe that my random collection of sold carbide printed circuit drill bits holds the split point down to smaller sizes.

Well ... my set is a "Made in USA" set, as sold by MSC a few years ago -- with a good HUOT index.

Good Luck, DoN.

Any drill could be reground with split points. There seems to be a misunderstanding among some that the points are attained or added by making a grind to almost the center of the web (at the back of the flute).

That's not how split points are attained. The back grind (approximately parallel to the flute spiral) is done first, then the cutting faces are brought back to where the points are optimized.

I discovered this method back in the '80s using an industrial toolroom drill grinder. I don't remember the maker of the machine, but it had numerous precision holders for almost any common drill size. I used to be able to make decent split points by hand when my eyes were better, but I have a difficult time getting good results now even with a good 3 diopter magnifier at the bench grinder.

And for the commentary in another post about whether drills are bits or not.. they are not. It's made it's way into the language, but that doesn't mean it's correct. A bit is something that goes in a horses mouth, said my machine shop teacher.

WB .................

manufacturer