I can't figure out why the things are as expensive as they are, I also can't figure out why they all aren't double enders. It is the ultimate tool
that lends itself to being a double ender. Center drills are double ended, not spotters. Sure would be nice if they ground a spot drill on
the back end of endmills. I'd pay a few more dollars for that.
I've pretty much given up on spot drills, especially carbide ones, I've got piles of them here that are all chipped up. I've got quite a few HSS
spotters too, and they seem to last and last. I used one 5/8 for like 3 years until an oops moment.
I don't get the geometry of them either, really not very good.
Lately, I haven't been spotting anything, either just slam the drill in, or I've been piloting with an 1/8" carbide drill(or 3/32), that works great when
drilling something that can't take a lot of down pressure.