Run-out on old mill

Hello everyone.
Long time lurker first time poster because I need a little help, or perhaps just a second/third/fourth opinion.

Earlier this summer I got my hands on an old Victoria mill (sold under the name Elliot in the US). It's originally a horizontal mill with a universal table, but mine has been outfitted with a vertical head instead. It lacks some of the features of a dedicated vertical mill, but it will serve my purposes just fine.
Anyways, when I got it it needed some love and I've spent my free time during the summer restoring the machine. When I got it the spindle itself had some run-out and the morse taper in the spindle had some dings and scratches that made this worse.
So I removed and cleaned the spindle, the bearings and everything else, mounted the spindle in my lathe and very gently reamed the inside of it with a morse taper reamer, made some other minor changes so it would better be able to take a ER32 collet chuck, and finaly I turned a new drawbar on the lathe.
Once I remounted the spindle and remeasured the outside I was glad to see that all the run-out had been eliminated. I mounted the ER chuck and read the run-out on this. It gave me a little less than 0,02mm, so less than a thou, which I feel I can live with.
However when I mounted my 12mm milling bit in the chuck and took a reading of this it gave me almost 0,1mm worth of run-out. I was surprised and tried to unscrew the collet and remount the bit. After trying this a few times I managed to eliminate some, but by no means all of the run-out. The Best I can do seems to be about 0,05mm (roughly 2 thou) wich is still way too much.

Now, personally I suspect that the fault lies with the ER Chuck and collet set I bought, since this is the first mill I own myself, and since I knew it might need some work I didn't spring for a high quality set, but rather bough some cheap Ebay stuff. As far as I can tell the machine is running pretty straight so it seems to me that the fault would lie with the chuck/collets, but before I run of to buy a fancy new chuck and collet set I figured I could ask you guys here if there is something that I might be missing? Is there some variable in the machine that might be causing this, some part I should troubleshoot before I just try to throw money at the problem?

I should also mention that everything else about the machine seems near flawless, I runs like a dream, is strong and quiet, stable as all hell and both the bearings and gears seem to be in excellent condition.

I would make sure the taper in the holder is clean and burr free. Check the collet for nicks or crud in the slots which might make it compress funny.
Finally, I'd check the taper ring in the cap where the collet seats to make sure it isn't cracked.
I've seen DA collets where the ring in the cap gets cracked from someone over tightening.

Egil said:

... before I run of to buy a fancy new chuck and collet set I figured I could ask you guys here if there is something that I might be missing?

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Throw a pin in the collet and indicate it. That will tell you if the runout is the collet or the cutter. Did you say Morse taper ? you can do the same thing with an off-the-shelf drill chuck adapter, or make something of your own. But for doing stuff at home ? I wouldn't worry about it.

I should also mention that everything else about the machine seems near flawless, I runs like a dream, is strong and quiet, stable as all hell and both the bearings and gears seem to be in excellent condition.

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I'd just use it as-is. Well, first I'd check to see where the runout is coming from, just to know. But after that, heck. .002" is just a touch over a brch

Hi Egil, If you are around Oslo we can chat off line or I can take a look at it. I presume we are talking about an inexpensive ER adapter and collets? Other than dirt/and or burrs in the spindle bore I would be suspect of the tooling, some of the cheap stuff is usable and some of it is not.

Luke

Well, the way I see it if you have .02 mm run out and them extend the spindle out with a collet chuck the run out multiplies. The farther you get from the spindle the worse it will get. Reaming a spindle is not the way to go here expecting perfection, grinding is the way to go.
You chose the ER set up for reasons I can only imagine (probably price?), truth is you would get better reading and performance with collets fitting directly in the spindle instead of stacking error on top of error.
Dan

real world machine spindle has runout
tool holder has runout
tool itself can be resharpened with runout and or not straight
.
the combination can add up. when you got hundreds of tool holders and tools and track actual runout of tool in tool holder on a optical tool presetter you can easily see runout over .010" often and common especially longer mills and drill bits.
.
what i do is only worry about the worst ones. replace, regrind, etc. sometimes collet holder has a hairline crack where collet seats. cracked ones need to replace

Thanks everyone for some helpfull pointers.
Checked the chuck and and collets again today, while I couldn't find any dirt or grit I did notice that the holder seems to screw on a little crooked and that the collets seem to have been more crudely machined than I first though. I also found an old chuck that came with the machine and mounted it. I didn't quite fit my new draw-bar and the bit wouldn't sit properly tight in the collet, even so it gave me far less run-out so I'm leaning heavily towards this being a problem with my cheap-ass chuck.

Whidbey: I live pretty close to Oslo, Nesodden to be exact, so feel free to send me a PM and we can talk, and indeed we are talking about some inexpensive stuff, so I am not surprised if the fault is with the tooling.

Danny VanVoorn: I have virtualy no run out on the spindle, once I extend it out with a chuck I get 0,02, and I know this will stack the further out I go. What surprised me was that it went from 0,02 when I measured on the chuck and all the way up to 0,1 when I measured the milling bit. Seemed like a very brutal rise to me. The interior of the spindle didn't have a lot of damage, just a few small burrs so I figured a reamer would do the job, seemed to work fine too. Never ground a spindle before, how does one do that?
Yes I went ER for economy reasons, mainly because I knew this mill might be a project and I didn't want to spend a lot of money on tooling that might get ruined as I was setting up the machine. Once I am confident that the machine is as good as it will get I am going to invest in some better equipment.

DMF_Tomb: I know that run-out happens in the real world, and I can live with a little run-out, no problem, but I do want to get rid of as much of it as I can