Chuck Not Running True?

[PAturner]

So the lathe I bought is now powered, running, and so far the tools I've ground cut well. Yay for that.
However, I've run into a problem that I'm very worried about. First of all, the chuck (really the backing plate I guess) does not spin all the way onto the spindle, and worse, the chuck does not run true. I am very wary of forcing the chuck on, because I can see that going all kinds of wrong. When I chuck up a round piece, it runs very very close to true- close enough that you have to look closely to see what's wrong, but noticeable.
I took the chuck off and looked at the spindle and that seems to be running quite true. I put the chuck back on and noticed the backing plate wobbling a little.

Based on this info, I have a few questions (numbered so they're easier to answer I hope)
1.) Based on the above, would I be correct in assuming the backing plate would be the first thing to check?

2.) could the problem possibly be solved by finding a way to spin the chuck all the way onto the spindle?

3.) If yes to number two, any suggestions on how to safely go about getting the chuck on properly? What kind of tools, cleaning procedures, etc should I know?

4.) If all else fails, will I be able to make a new backing plate with only a lathe and a drill press?


And before anyone mentions it, yes, I absolutely need a dial indicator- I'm working on that currently.

Thanks for any help!


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[Ulma Doctor]

1) YES
2)YES
3) see below

if you can remove the chuck, do so

just place a piece of wood (or thick cardboard doubled up) to prevent the chuck getting dropped on the ways
inspect the spindle threads for damage and bits of metal, clean with a brass wire brush
inspect the chuck threads for damage or bits of metal, clean with a brass wire brush
if there is no damage seen, apply a drop or 2 of light oil to the spindle threads and try to reinstall the chuck

4) YES! you sure can

 

[PAturner]

That's the only imperfection in the threads, it's quite a small little chip and its early in the threads so I doubt it's the issue.


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[Ulma Doctor]

the dreaded red X

 

[Ulma Doctor]

i can't see the chip,
but if it scores the threads as it goes on, it may cause some interference

 

[PAturner]

I'm not sure what you mean by score the threads. It spins on well past the chip if that's what you mean


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[Ulma Doctor]

that's a good sign then
is there any damage to the internal threads of the chuck?


scoring refers to worn or damaged thread contact interface
it may be very slight or very pronounced.

 

[PAturner]

From what I can clearly see, no- however I cannot see all the way in as I can't get the backing plate off. I'm soaking the bolts in wd-40 overnight and will get back tomorrow. From what I can see though, there is a very clear line of clean metal and then a bit of surface rust. Very light, could scrub off with 0000 steel wool if the part were flat, but it's there. The clean metal is towards the headstock end of the threads that screw on first, so I have a creeping suspicion that this could be part of the issue. Perhaps a vinegar soak when I get the backing plate off and see if it helps?


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[Ulma Doctor]

vinegar will work and take off some rust too
it may leave the metal a little gray looking

 

[PAturner]

Also, the chuck is a three jaw-
Could I possibly get around any runout issues if I got my hands on a 4 jaw independent chuck?


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