When do you know it's time to replace carbon rollers on transformers?

[Birds]

The rollers on my KW are of an unknown age.  How do you know when it is time to replace them?

One carbon roller is starting to get a bevel on one edge.

Thanks,

Chris 

[otftch]

If you've already taken it apart, replace them for GP.Usually you will notice the handles get stiff or scratchy when you move them.If they rotate freely you are usually okay.They're not that expensive to replace if you do it yourself so do it now and don't worry. I'd replace the one with the bevel anyway but it don't make much sense to replace just one.

                                                          Ed

[Birds]

Thanks Ed.  They'll get replaced since I'm doing other repairs in the KW.  However, I appreciate knowing how the handles begin to feel/sound when they are worn out for down the road.

Chris 

[lionelsoni]

I wouldn't worry about a bevel.  If the roller is not perfectly perpendicular to the winding surface, I would expect it to wear that way.  Replace it if it's worn out of round or seriously undersized.