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Discussion Starter #8
spiral pattern, everyone has an opinion, i've used cross dilled rotors on drag cars , turned them blue , stopping a 3000 lb car with small front wheels and 15x 33 goodyears on the back, from 165 mph tends to make some serious heat, show me some of these cracks that some of you are seeing, I,ve not had the opportunity , :wink: :wink:
 

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Discussion Starter #9
BHODGES3 said:
Heh, then it is kind of like snow-flakes... no two cross-drilled rotors will have the same crack pattern.
and i will be the first to post a picture so you can have a good laugh, :oops: :wink:
 

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Drive True
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As a former structural integrity guy, I will tell you that holes and slots are areas of stress concentration...stresses around holes can be at least 3 times the amount of the stress far from the holes. (I'm not sure what the stress concentration factor is for slots, but if you leave sharp corners in the slots, you're begging for trouble.) You can minimize this by making the holes large enough and also making sure they're spaced far apart enough. Where I work, we use 4 times the diameter of the hole + 0.03", which looks like from the pics you far exceed that...that's good. The holes also need to be flawless, any little scratches in the holes are where cracks will initiate.
 

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Drive True
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Re: Cross Posting

Ken Reich said:
the holes are chamfered, they did a nice job, :wink:
That'll help a little. But what happens if the crack initiates in the center of the hole? Not much you can do there.
 

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Drive True
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Chamfered is where an edge is filed down so that you don't have a sharp corner. For example, if you had a part that had a square cross-section, chamfering would make the cross section look like an octogon. The edges are less sharp and less likely to chip off and create a crack initiation site.
 
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