How much runout is acceptable for a drill press?

The best way to tell the older (made in USA) chucks from the later offshore models is how the name and model number are displayed. The older models have the name and model stamped in while the newer ones are etched in or printed on.
 
I agree that the spindle taper and chuck taper may not be a good match. Take the cuck off and coat the spindle taper with Dyekem or a marker. Install the chuck with just a slight rotation as you seat it. Take it off and look @ the rub marks on the Dyekem/marker. If there is little evidence of contact all around and at least 3/8" up/down, (more is better) the chuck will not center. Is the chuck retained with a screw or pressed on? If it is pressed on it should be very tight and require wedges to remove.

I have an old ('70s) Jet drill press that has virtually no runout on the taper but the original chuck had lots of it. I put new bearings on the spindle and a new ball bearing chuck. Using a gage pin & a dial indicator I get .0040+- runout.
on my jet mill with a PM keyless chuck I get .004. Checking the spindle there is about .0002. So in both cases, it's the chuck.
I'm pretty sure that a drill bit makes it worse. To manage the drill bit, Use a spotting bit first. Also the shorter the drill bit the better. Use screw machine bits when possible. Just got to have better? Drill undersize & ream. You can make 3 corner reamers for short runs yourself. (Use drill rod or turn it to other sizes.)
 
Thanks for all the suggestions.
I will play around with it some in the next day or two and see what I come up with.
Like I said, it is not for precision work, but I was just not sure of what was acceptable and what was not.
 
Chuck up a nice dowel pin and check run out. Give the chuck a firm tap with a dead blow just like you would with a three jaw chuck to further center a longer part.

Then take the dowel out and re-chuck the dowel. I've removed a couple thousandths runout this way.

I can hear the can'ts and shouldn'ts but it does work and it stays put just fine.
 
That runout in and of it's self won't bother you a bit. You're still inside a center punch, the drill will find it's hole.

Drill presses, being "not milling machines" don't have the rigidity to force a cutter to stay on center. Nor do they have the rigidity to force a cutter off center. Nor are most drill bits in that drill's vocabulary rigid enough to care how rigidly they're held. They'll bugger off on their own just as easy on a mill as they will on a drill. You also might find that if you started measuring different points along your drill bits, they might not be as straight as you'd like to think they are anyhow. Don't go getting the micrometer back out.... You were already good with that tolerance, the world is OK with that tolerance. They worked fine up until now.

Basic rules for drill pressing things:

Center punch critical work.

If you you have a particular material(s) that you have a hard time getting a drill to start "riight where it lands", center punch that too.

If you MUST use a jig or fixture to locate holes in an "unmarked" condition, start the hole SLOWLY. Hard on drills, but just like drilling on a lathe, if you start slowly and gently, the drill bit will find it's center. Initially anyhow. They'll almost always wander on deep holes, but there's pretty good workarounds.

If that little bugger is big enough to do the work you've got lined up for it, then set it up as best you can, bolt it down to something heavier than it is, and use it. Drill presses inherently have metrology issues, it's just how they are. Use the drill press. Address performance issues. Preferably without micrometers or dial indicators. If the runout is any more than just barely visible at the tip of the drill bits you're using, before you get out the dial indicators, try clocking the chuck in a couple of other positions about 120 degrees from where you started. Yeah, I'm guilty too, but measuring drill presses to thousandths of an inch is best saved for chasing down where damage occurred, and how to fix it. They're pretty floppy overall, even the big ones. So having it more accurate than it's flexyness and overall cast in and, machined in "tolerance" is pretty much not going to get you any further ahead. STOP! Put the micrometer down. You don't wanna know about that stuff either. Use the drill press and see what it does.
 
I piddled around with it a little this afternoon and tried some of the suggestions.
I got it down to 3 thousandths. So I am calling that good enough.

I am actually not using it to drill holes. There is a good chance it may not drill a hole in its life. I bought it to roll crimp shotgun shells.
I reload my own 12ga shells as well as cast my own slugs. I do a good bit of roll crimping loading both buckshot and slugs.
I have done it with a hand drill a good bit, but always get uneven crimps no mater how straight I try and hold it.
I tried using the drill chuck that came with my mill and I can not remember how much runout it had, but I was a good bit. I only found it out when I was getting very poor crimps. The issue came back to the excess runout.
I bought a new R8 chuck mount and chuck from shars and installed it. Runout was only like 1 or maybe 2. The crimps greatly improved.
It was just a pain to do it on the smithy granite as I usually keep it set up for lathe work. So having to remove the lathe chuck, then install the drill chuck to the mill head, then switch back when I am done was a major pain. Plus having to carry all the non crimped shells out to the shop and try not to drop any.
So that was the main reason for the benchtop drill press. Something I can keep in the spare bedroom/reloading room and be able to roll crimp in the house.
I just tested the roll crimper on a empty hull and it seems to be working fine.
 
You must log in or register to reply here.
Back
Top