"lines" in brake discs

[Toilet Duck]

Evening all,

Hoping the resident experts can give their opinion on whether the following is cause for concern. I have Alcons front/rear and today noticed that there appear to be extremely fine "lines" on the discs. I don't want to use the word "cracks" as I really don't know if that would be correct (I hope not!). Its more pronounced on the fronts, but still evident on the rears. Quickly checked front disc thickness and they are in the region of 20.90 - 21.00mm thick, I don't know what the service limit is? Pics are all from one of the front discs:











Cheers

[Toilet Duck]

Just found this on Pistonheads; although not Atom specific hopefully its answered my question and the "lines" are "acceptable"

http://www.pistonheads.com/gassing/topic.asp?t=1068444

[dc5ian]

i wouldnt worry too much about it...

[Northnoble]

I wouldn't worry at all!!

[smokin]

This note from ebc also says not to worry, just keep an eye on them or get them Pro Cut (like I did last year)

http://ebcbrakes.com/articles/surface-crazing-or-cracking-on-brake-discs/

Can't recommend the disc skimming enough

[smokin]

After

[Toilet Duck]

Thanks chaps,  much appreciated 

I actually took all the discs off as I want to get them skimmed at the place I'm taking my flywheel  for a look tomorrow 

Cheers

[smokin]

Main advantage of the Pro Cut system is that skimming them while on the hub means they are absolutely true to any run-out in the hub no matter how small.

[AtomMadStew]

I've used a pro cut machine 100's of times - providing it is used properly it is a very good piece of kit. If you manage to find a garage with one ask them either to turn the cutting tip round to a new tip or fit new tip bedore skimming. The tips cut about 10 discs (both sides simultaneously) and after a while so go blunt. A new set of tips will do a sterling job.
Typically takes about 10-15 mins a side.
Shouldn't take more than an hour to do from arriving to driving away and only takes about 0.3mm from the disc thickness on a minimal skim.
Find a main dealer (honda preferably) don't go to a kwikfit or Charlie Browns - I've never been to any of them places and found someone that either knows how to fix a car properly or operate simple machinery.
I'm not sure if we have a pro cut at our place anymore.
Stew

[Driver]

I wouldn't get discs cut just because of a visual issue. Only if they were warped. The more metal you take off the quicker they'll heat up under heavy use, the quicker the fine fissures will return, the easier they will be to warp and the quicker you will be at min thickness and be looking at complete new discs altogether.