Depends on what you're doing. Low run-out on a drill press makes like easier because the drill starts where it's aimed. But twist-drilling is low-accuracy process, so you can't expect too much of it.

High run-out on a drill-press isn't a disaster either. When the drill is spinning, the drill balances around the rotating axis, compensating for worn bearings. If the drill is lowered into a spot-punched, or centre-drilled hole, and the work floated into alignment with the drill, the drill will go in straight. But it won't stay straight if the spot hole is misaligned. A low run-out drill stands a better chance of correcting for a wonky start, but a good operator can compensate.

I've never bothered to measure the run-out on my pillar-drill. Worse than yours I guess, but it does what I want! That said, I prefer to drill with my milling machine. I start with a spot or centre-drill, then switch to a jobber to do all the hard work.

Don't be surprised if twist drills wander or otherwise misbehave in metal. Learning how to get the best of them is all part of the fun!

Dave

My drill press seldom gets used to drill anything of importance as I tend to do all my drilling in the mill as the DRO makes a better job of positioning than marking out. But sounds like your chuck/arbor is not ideal. I get 0.03mm on my most commonly used 0-10mm keyless chuck in the mill measured when holding a 10mm ground rod

Edited By JasonB on 10/01/2023 19:25:43

What's "at the morse taper" ? the outside is irrelevant, it's inside the taper that matters, I just checked my drill, rotating the spindle by hand shows no more than 0.002mm flicker on the dti.

What's a precision rod? I have a feeling you're using silver steel, but the quality of this can vary between suppliers, Rennie supplies good quality silver steel, other budget material I've purchased from reputable suppliers is a noticeable drop in ground finish, I wouldn't recommend this for checking accuracy.

A good quality carbide end mill might be a better bet .

Where you need to place the dti to check runout 👇

What machine is it?

When checking these things you need to assume every part you add to the mix could potentially be the problem, or part of it.

Which is why you check the spindle bore first.

If you measured the arbor without the chuck at 0.03mm then the chuck is probably the cause of most of the problem, I'd just use it as is until you know where the problem is?

No point even worrying about it unless you have the means to test it.

I think Rohm lists runout for their various lines of drill chucks. Not THAT impressive from memory & also from memory last time i checked my 'best' drill chuck had about 2 thou runout.

Being a quality firm their figures are likely to be on the conservative side.

Like others have said drilling isn't a precision opperation( I was a bit miffed when i found this out) & i'd expect a decentish jobber drill to 'find it's way home' so to speak.

Andrew has still not specified the units of his 0.03 so we still do not know just how bad it is.

Les.