more problems with my chucks ....sigh.......

[Richard Kennedy UK]

I am getting a bit fed up now.

I have 3 chucks 2 axminster super precision chucks and a versachuck (exactly the same design as the axminsters but takes other makes of jaws) I have purchased the backplates to fit these chucks to suit the 3520b spindle fitted them and found that the chucks themselves appear to run true but when fitted with a set of jaws the jaws don't. I have messed about with the back plates andI thought I had sorted the issue but got distracted with a spindle order so haven't been using the chucks but today put a lump on to find it running out I cant understand what is going on but its really frustrating.

I have cleaned the jaws and chucks re tightened all the grub screws tried different jaws on different chucks and yet still things seem not to be running right I dont remember this happening on the cl3 and the VB is fine I just dont know what to do next

Any ideas would be welcome at this point I really dont think its the spindle like I say without the jaws the chuck runs fine but it seems so temperamental.

Has anyone had this kind of problem before would a new chuck with a direct thread be the answer its expensive but if its the only option I guess I will have to bite the bullet

Help!!!
:confused:

[Tom Wilson66]

Since it seems to be the jaws on all of the chucks, just wondering if you are putting the jaws on in the right order. The jaws on my chucks are numbered and I always match the number on the jaw to the number on the slide. When I first got a chuck, took me a while to learn to do this, and couldn't get consistent results till I did.

[David E Keller]

Hmmm... Sounds like a puzzler, Richard. If you're saying that those chucks run true on other lathes, then I can't imagine that the problem is with the chuck or the jaws. If it's not the spindle(unlikely since your spindle work is going OK), I have to think the problem is with the insert. I wonder if the addition of jaws just makes the runout more noticeable since they project further away from the headstock than the naked chuck?

[Terry Murphy]

Check for numbers or dots.
I always close the jaws before tightening them.