Sorry Tom, I don't agree with the previous posts mate.
The first photo looks like there is a few marks around the centre bands and the nib on the right hand side looked like it's got something wrong.
The bottom ones looks like the nib on the middle one is off set and a ridge in one side.
Might be the picture or the way the light is but I have seen much better from you.. Only my opinion and can tell me to bogg off and walk mate.. :
Sorry.
Thanks for the comments I never get offended the nibs are fine I think its the light taking pictures is not my forte, I have been getting a dark line around the ends, can't think why
It may be that the bushes are taking a bit of them when getting a little close and its transferring to the wood when you polish.
Are you using a sanding sealer ?
The dark ends may be caused metal dust from the bushings when sanding.
I TBC without bushings when sanding and finishing.
Les
It happens while I am turning I thought it was the bushings worn down so used some new ones, still happens. I think its me catching the bushings with my chisel.
I agree it could be, but I'm certain it's down to sanding over the bushes and the fine metal may be being transferred to the blank.
What grit are you using to start with Tom?
60 going down to 240