concentricity

[matt12805]

running hss .343 drill and having concentricity issues...we are cutting cast metal so that may be one of the problems but even running 316 ss we still run into problems...our machines are also a little out of line usually i just eye my drill up and watch it cut to make sure it is cutting straight on my first cut...just wandering if you guys have any tips or suggestions...im running 45 sf and feeding @ .006

[Mcgyver]

to diagnose, this needs a lot more info.....how far off are things and what's the goal...lining things up by hand? is this a cnc or a drill press? are you spotting the hole first? what exactly is the problem; ie drilling over sized, hole not where its supposed to be, hole isn't straight etc.

first thing to look at with a drilling problem is the drill grind itself, that's assuming basics are covered...its the drill grind that keeps things straight and inline more than how eccentric the chuck is

[grinder55]

being concentric! means outside dia. and inside dia. are running together. so the work holder and tooling need to be in line. depending on your tol. so using your eye to locate i assume you dont have close tolerances. dependining on tool length such as drill and material ,speed and feed make a difference. there are so many variables in mach. would have to look at your application! sorry! hope i could help!