How much is too much...

[Tinbasherdan]

I'd mount the 'collet chuck' in the mill and a lathe tool to the mill table and skim the OD. Should then show no runout. Stick that in the 4 jaw on the lathe, clock it, then recut your taper for the ER40 collets

That’s going to be the next job I think. Spindle itself is running true as I’ve clocked it off the collar and the spindle nose itself-0 runout.

 

[Tinbasherdan]

i'm unfamiliar with your mill, but does the head tilt? And does it have a quill?

No and no, fixed head.

 

[Tinbasherdan]

Ah shame you could of cut the taper in situ.

I’ll work I’m sure

 

[Tinbasherdan]

So spent a couple hours tinkering today, remade the nose and spent a lot more time clocking everything that could be clocked. Got it running within 4 thou, certainly good enough for what I want, however at some point it may end up with @Pete. for some fettling of a more accurate nature