[Newbie] Unimat Sl, Not True.

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A few weeks ago I got an Emco Unimat DB SL and disassembled it for some servicing, after assembly however something isn't right at all anymore.

At first I thought the spindle got bent somehow but I visited a shop today and they helpfully measured it and it turned out that it's off by 4/100th mm (withing manufacturing tolerances according to the manual), so that can't be it really.

Next I took a straight rod and put it in the chuck (and repeated that later with a collet) and a drill. They both seem to be true too.

However, as soon as I screw the chuck on to the spindle it's off again by quite a bit. A 150x10mm rod would completely miss the tailstock. In short the lathe is completely unusable as it is now, but was usable when I got it.

I'm thinking something might be funky with the threads, but how would I find out/what should I do?

I hope I've been clear enough that you can kinda figure out what I mean., Otherwise please do ask!
Thanks a lot!
 
Do you mean to say that the spindle is aligned to the tailstock, but the chuck does not align with the spindle? From the pictures I looked at, the headstock seems to rotate about a vertical axis, could that be the problem?
 
Sounds like your headstock is out of alignment with the tailstock. If your unit has the headstock that rotates then check it will need to be indicated to the tailstock.
 
I am with Jim Dawson, sounds like your headstock is out of alignment.
Just to be safe though, can you rotate the tail stock clamping block 180 degrees? I doubt it is possible, but the tail stock might be sitting off-center.
I don't have one, but I have always admired them. My understanding is they only go together one way and there are pins that align the head stock.

If the head stock and tail stock are all assembled properly, then about the only thing it can be is the ways are twisted. Either a piece of gunk is under one of the ways, or you tightened up one end before snugging down the other. Try loosening all the bolts that hold the ways to the base and re-tighten them by first snugging them lightly, then a bit more, then full torque (the torque should be pretty low, so don't crank them down). Make sure the base is sitting flat. Best thing would be to flip it over on some parallels one a surface plate and make sure they ways a planar.
 
Thanks, but I'm pretty sure that that isn't the problem (yet, I'll double check the ways and the tailstock when I've hopefully resolved the other issue to make sure that's aligned!)

I'm having difficulties explaining myself being pretty new to technical terms that I wouldn't be using on a daily basis..
1) The headstock has a locking pin which is in, so in theory that should be aligned-ish.
2) My problem only arises when I mount a 3jaw-chuck or a collet to the spindle. Before mounting them everything is fine and aligned (well, I can only check by pushing something into the spindle and mounting the tailstock)
With the 3jaw-chuck or collet however the chuck/collet will oscillate visibly and with a workpiece (any workpiece) the end of the workpiece would wobble so much that it'd turn circles around the Centre on the tailstock..

That lead me to think that the spindle had received a heavy knock somewhere and was bent, however, as measured in the shop (on a lovely schäublin, I can't do a thing yet but kinda fell in love..) it seems to be straight enough!
 
If the test rod starts true, then progressively becomes more eccentric as it furthers the headstock (cone shaped pattern), the chuck or spindle is wonked. If the test rod orbits in a cylindrical pattern, the jaws are not installed in the correct order, as Chips and More explains above.
 
I agree it sounds like Chuck jaws since you say it is orbiting. While the chuck I'd of tho put a center in your headstock & check alignment with a center in your tailstock. You can pinch a steel rule in between the two centers to exaggerate the amount it is off. Rotate the headstock & repeat to see if it is still orbiting. Then start checking the chuck.
 
Your last description was pretty good.
Does the collet fit into the bore, or does it fit into a collet chuck that threads on the spindle.

I am thinking the spindle face has a ding in it or something causing the chuck to mount cock-eyed.
 
Post a picture of the lathe and chuck. that might help .
 
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