sloted rotors

[Oldblueaccord]

I'm saying Carroll Smith's theory is wrong. I assumed you wanted to know why. People using common sense are agreeing with me, I just have the education, understanding and material to back it up. The TRW post clearly supports what I've been saying, you should read it. Do some basic online research. Carroll Smith's lemans experience will never overthrow the iron carbide model, ever.

BTW I'm not a fucking scientist. I gained my knowledge through education, not some pain in the ass online article.

Oldblue: I'm assuming you are saying that the diamond tooling is too fragile and expensive to use on a cheapo brake rotor job? Because thats the impression that I had. I've used carbide inserts to make an interrupted cut on 316 Stainless before and had excellent results, though I knocked the cutting speed back to about 30SFM. I've never had luck using HSS on cast brake drums, the abrasiveness destroys the tool edge within seconds, even with minimal speed and a moderate feed. (and a neutral to positive rake ground on the bit) We parted out an old giant brake lathe awhile ago and I remember it having a brazed cemented carbide toolbit installed.

I am saying yes on the diamond> I was answering the other guys response really.

Using an amaaco brake lathe , I'd assume, they run super slow least they did on the late 80's when I used one last that HSS works but not having one I coudn't tell you. I think I have a rotor here at work I might try. We wanted to see if our lathe would go slow enough to leave a good finish and how bad the run out would be

We really need to thank CAH for starting this thread in the first place. Only he could start this shit.

And just to add I have always suspected but cant prove it that most rotors are cast steel and not iron at all but I' ll throw that out in one of Kelvins threads just to spam it up someday.

wp

[2oodoor]

I use diamond round bits with no problems.

I was mistaken, the round bits i use are carbide not diamond. I get them from Kent Automotive

[Kelvin]

I'm going to have my automotive engineer friend come into this discussion. I don't believe a barely graduated chem major knows more than Carrol Smith.

[2oodoor]

:

I'm going to have my automotive engineer friend come into this discussion. I don't believe a barely graduated chem major knows more than Carrol Smith.

ok I forgot what was being debated here. Can we refresh the points in bullet format so they may be addressed individually.
metaphor: brakes faded delivering point/slid into brickwall with this argument/ grabbing e brake engineer friend it's a joke , man

[Ichiban]

I'm going to have my automotive engineer friend come into this discussion. I don't believe a barely graduated chem major knows more than Carrol Smith.

Go right ahead, if he has any knowledge of metal, even at all, he will side with the iron-carbide diagram.


BTW Carrol Smith doesn't know anything, he's dead.

[Oldblueaccord]

I was mistaken, the round bits i use are carbide not diamond. I get them from Kent Automotive

well truefully the only thing i ever seen diamond was a dressing tool



I took a crack at an old slotted rotor I had at work before I got off shift. Cut it at the slowest speed on our lathe and it cut really well. I just spent about 10 minutes on the setup and that tool is prolly as old as I am.

Its defintely cast iron.



wp

[Ichiban]

well truefully the only thing i ever seen diamond was a dressing tool

I took a crack at an old slotted rotor I had at work before I got off shift. Cut it at the slowest speed on our lathe and it cut really well. I just spent about 10 minutes on the setup and that tool is prolly as old as I am.
Its defintely cast iron.
wp

Comes off in a grey sandlike powder instead of chips? That would be cast. What were you cutting it with? HSS or carbide?

[Oldblueaccord]

That picture is the cutting tool.


wp

[Ichiban]

I misunderstood.

So obviously HSS cut it fine for you, even with the slots.

[Kelvin]

I misunderstood.

AHAHAhaha.

Okay guys: Who do you trust? A guy famous for his racing career, experience, and has written some of the best books on setting up a race or street car in the business?

Or some self proclaimed metal expert who can't even tell a cutting tool from metal shavings?

[2ndGenGuy]

AHAHAhaha.
Okay guys: Who do you trust? A guy famous for his racing career, experience, and has written some of the best books on setting up a race or street car in the business?
Or some self proclaimed metal expert who can't even tell a cutting tool from metal shavings?

You come on the forums as a noob, whore up all of the brake threads, call everybody on here idiots, bullshitters, and dumbasses and so far haven't been able to back up anything with more than a SINGLE link. No evidence from yourself. Carroll Smith isn't that famous either. We've got people from all over saying you are wrong, people with combined experience which probably totals up more than Carroll Smith's.

And by the way he wasn't referring to the picture. You're so illiterate, you take things we say out of context, and you don't answer the majority of the questions we ask you. Also, you are really good at avoiding any points that completely prove you wrong. You've completely insulted the community from which you're in here to get information from.

I think most of the problem here is your shitty attitude. Instead of provoking mature commentary and discussion, you just come in and start telling everybody they are wrong and to read some lame article, then toss insults at them. That's right, that article is LAME. Even good writers, and experienced people are wrong. Just because Carroll Smith hasn't seen a warped rotor, doesn't mean it doesn't happen.

Have you ever seen someone get struck by lightning? No, I didn't think so. Does that mean it doesn't happen? Of course not. You may perhaps be older than me, but you really need to grow up. Quit being this internet badass who thinks he's so much smarter and better than everybody else who contradicts him. Open up your mind to something more than one goddamn article. Please for the love of god. Or just quit posting. That would be excellent.

[Ichiban]

Uh, to be honest at first I didn't even look at the picture until after I posted. So why don't you tell me how each different metal cuts, which angles you would grind on the lathe bit, what speeds and feeds to use. To start, what angles are ground on that lathe bit? Why are they like that? Here's a fucking clue: The way the Cementite, Ferrite and Graphite forms in cast iron as it solidifies. That is why every lathe bit is ground as it is, but you wouldn't know that because Carrol Smith never told you that. You wouldn't be able to tell the difference between Martensite and it's tempered form Bainite after heat treating. You wouldn't be able to tell why a shaft cuts differently than that material normally would because you don't have a clue about how the grain size varies due to work hardening and heating/quenching.

Oh wait, everything I know about metal grain structure is wrong because Carrol Smith said something out to lunch in a field he doesn't even routinely deal in. Guess I'm a fucking idiot. I guess hard braking causes Cementite to magically appear in iron. I guess I wasted thousands of dollars on fucking school. I would assume trowelling concrete causes gravel to form inside, right? Someone on the net told you so, it must be right, yeah?

Fuck off.

I've studied to great depth the causes and effects of what's inside iron and steel, and how varying and modifying them changes things. You come along proclaiming that left is up and the sky is goddamn purple and expect me to believe it? That cementite theory of yours is GODDAMN BULLSHIT. Maybe you understand caps better. Braking DOESN'T CAUSE CEMENTITE TO FORM.

I thought that the textbooks and links and other shit would clue you in, but you obviously can't swallow your pride and do a little online research. I looked around even at wikipedia and a few other quick google results, and there are a pile of pretty reasonable descriptions kicking around....including the TRW link you posted. Which you didn't even read yourself, which is clear. Or you would realize that you are stupid.

You obviously have never welded. Some of the dumbest people in the world have more knowledge than you in terms of metal warping due to overheating. They will all assure you that metric tons of metal are warped due to heat every day. But you won't understand this because Carrol Smith told you it won't happen.

You obviously have no respect for people on this forum. You continue to preach bullshit, even when other people question it as well.

Since I can't ask you to do the research on your own and figure out what actually happens in this situation(even with common experience and common sense guiding the way) then all I can hope is that you go away.

[2oodoor]

wow, I must say after all is said and done here, even with two decades of automotive and metal fabricating under my belt < I still learned something from the information presented.
Other than the condesending tones of the noob, It is one of my fav threads.
I must admit though had it not been for the conflicting concepts, the brunt of the most usefull information likely would never have been presented.

[Kelvin]

Carroll Smith isn't that famous either.

Yeah, actually he is. "Engineer to win" and "Tune to win" and "Drive to win" are huge successes in the book industry. The reason you don't think he's famous is because you're ignorant.
Also, I DID bring personal experience to the table, like I've explained many times, I've had ZERO pedal pulsations after reading his ideas, adopting them, and switching to pads with super high max operating temperatures.

We've got people from all over saying you are wrong, people with combined experience which probably totals up more than Carroll Smith's.

What a joke. OF COURSE THEY ARE. That's because this is an old wive's tale. I suppose 'swimming after eating will cause cramps is BS' is something that "MOST PEOPLE" would disagree with me on too, but it is false.

I think most of the problem here is your shitty attitude.

Or that you're ignorant. If you weren't so ignorant, we wouldn't have a problem. Now run along, and keep telling yourself Carroll Smith isn't famous, and that all his books are BS, even though automotive engineers cherish them as biblical.

I guess hard braking causes Cementite to magically appear in iron.

Um... yeah, actually it does. Read the link I posted. Cementite is formed under really high heat. ..... and..... wait for it.... when you have uneven pad deposits, a lot of the time the high spots will 'glance' off the pad on every rotation, even if you aren't braking. This constant friction, this constant rubbing on every revolution causes heat, and without any time period to cool off, the rotor can reach EXTREMELY high temperatures. And what happens at such high temperatures?
YOU CAN MAKE CEMENTITE! YAY!
http://ws.ajou.ac.kr/~powder/files/P...2011-20-06.pdf
Read that again. Now read the 'differen phases' that cast iron goes through, after being exposed to different temperatures. There is the ferrite iron phase, the austenite iron phase, the delta iron phase, the graphite carbon phase, and finally the IRON CARBIDE (CEMENTITE) phase.
Here's a graph so I appear as scientific as Bill Nye up there:

Notice how it talks about cementite 'breaking down' with enough time and temperature. WHAT?! METAL'S COMPOSITION CHANGES!?!?! OMG!

Here is a chart of 'transformations' that occur in cast iron. I understand some cementite exists in ALL rotors, but it is more or less 'evenly distributed' throughout the rotor. What happens under high temperatures is that the molecules IN the rotor, just like any other thing heated up, start to break bonds with each other, and 'rearrange' themselves. The problem is uneven pad deposits, if scuffing a pad on every revolution, can quickly get to insane temperatures in LOCALIZED REGIONS OF THE ROTOR, causing cementite 'clumps' to form, which will NOT WEAR THE SAME AS THE REST OF THE ROTOR.

This is the SAME cast iron after being treated with different temperatures. NOTICE THAT IT IS DIFFERENT. Now imagine only heating up ONE part of your rotor, the part with a really 'high' pad deposit', which is hitting your pads on every revolution. This will cause the metal's molecular structure to change in just that localized region, resulting in a rotor that will NEVER wear evenly.

This one is also important. It states that silicon is required for the creation of cementite. Now, if your pads have ANY 'silicon' in them, which they most certainly do, this means that at really high temperatures, with a layer of 'pad material' on the rotor, that CEMENTITE CAN FORM. Bill Nye disagrees with me, but the proof is right here in front of your eyes.
Finally, the different phases and kinds of cast iron all have different wear resisitence:

I rest my case.

[HostileJava]

Yeah, actually he is. "Engineer to win" and "Tune to win" and "Drive to win" are huge successes in the book industry. The reason you don't think he's famous is because you're ignorant.

Stay with the subject at hand, if you continue to attack members personally you WILL find yourself with a temp ban. Also learn to use the edit button, there is no reason to post twice in a row.

[HostileJava]

The only reason I attacked him is because he was attacking me. I'll report his posts now.



Personal attacks.

That warning was for everyone in the thread really. Please don't' waste your or my time reading through the whole thread and reporting posts just to prove a point. The reason I quoted you is because you are the instigator. You can prove a point without acting like an ass. The discussion can get as heated as you want, but don't be petty and start attacking each other, it really has nothing to do with what you are discussing.

:
ok I forgot what was being debated here. Can we refresh the points in bullet format so they may be addressed individually.
metaphor: brakes faded delivering point/slid into brickwall with this argument/ grabbing e brake engineer friend it's a joke , man

Yes let's get back to talking about the pretty pictures of my brakes

[Kelvin]

So does this threat of 'temp banning' apply to 2ndGenGuy and GuyWhoHatesMyCar also? Because I'm sick of being attacked.

[MessyHonda]

seee you made baby 3geezus mad now....

[HostileJava]

So does this threat of 'temp banning' apply to 2ndGenGuy and GuyWhoHatesMyCar also? Because I'm sick of being attacked.

Yes it does, now stop whoring up the thread making sure that everyone will be punished equally. If you have questions about the discipline system read the TOS or PM a mod/admin.

[2ndGenGuy]

Actually, the problem isn't that I'm ignorant. The way you called guyhatesmycar a "hack" essentially is pretty fucking rude. And to go quote what I wrote, and say "I'm tired of your BS" is called "ATTITUDE". Maybe you need to look it up in a dictionary. And then to say sarcastically to LS1-Inside "oh look another genius" is also pretty fucking rude.

I don't give a rats ass if cast iron CAN turn into cementite, the fact that you say that it ALWAYS DOES is not proven by anything. You keep saying that all brake shudder is caused by cementite, and I still disagree. Proving that cementite can happen (though I'm not convinced 100% you've proven that it happens in brake applications), doesn't mean it ALWAYS HAPPENS. It also doesn't prove that rotors can't warp.

Your last post (being the best one you've posted so far and being how you should have posted a LONG TIME AGO instead of insulting people) only shows that iron, when combined with silicon forms cementite at EXTREMELY HIGH temperatures. Most braking applications don't see those kind of high temperatures. Most people never even experience brake fade in their cars. For temps to get that high, long, hard, repeated braking is required. Likely never seen on the street. And besides that, how do high-temp brake pads PREVENT this "cementite" condition?

Well sir, they can't. The fact that they're resistant to high temperatures only means that they won't transfer heat to the brake fluid which causes the fluid to boil which causes brake fade! THE PAD IS STILL MAKING CONTACT AT THOSE TEMPERATURES. Which means that high-temp pads, according to you, will still make cementite. Since there is pad material unevenly making contact with the rotors your rotors should be shuddering. This is what makes all of your arguments completely un-credible.

Explain to me how your high-temp pads have prevented your brake rotors from forming cementite.

Also, you still haven't answered my question, why do you get your rotors turned as part of a normal brake job. It doesn't make any sense and completely contradicts everything you're talking about. Again, why do you get your brake rotors turned? Why do you get your brake rotors turned?

[Kelvin]

Your last post (being the best one you've posted so far and being how you should have posted a LONG TIME AGO instead of insulting people) only shows that iron, when combined with silicon forms cementite at EXTREMELY HIGH temperatures. Most braking applications don't see those kind of high temperatures. Most people never even experience brake fade in their cars. For temps to get that high, long, hard, repeated braking is required. Likely never seen on the street. And besides that, how do high-temp brake pads PREVENT this "cementite" condition?

You didn't read what I wrote, or what Carroll Smith wrote. It isn't BRAKING that causes it, it's UNEVEN PAD DEPOSITS. I'll talk you through it, one more time.

1. You install crappy pads with a low max operating temp.
2. You properly bed the pads, putting a smooth even layer of pad material on the rotor.
3. You are driving 'spiritedly' and get your brakes pretty hot, and come to a stop, or just slow down enough to transfer even more pad material 'unevenly'.
4. This 'uneven pad deposit' is thicker than the rest of the pad material on the rotor. Now, if this 'deposit' hits your pads on every revolution, it does NOT REQUIRE BRAKING TO CREATE HEAT. Driving on the freeway will lightly hit that 'thick' pad deposit on your existing pad with every revolution, creating MASSIVE amounts of heat in very localized regions of the rotor, right on the surface of the rotor, right under the pad material. It is this area that will create cementite.

Which means that high-temp pads, according to you, will still make cementite. Explain to me how your high-temp pads have prevented your brake rotors from forming cementite.

They will prevent it by preventing UNEVEN PAD DEPOSITS FROM OCCURING IN THE FIRST PLACE. If you can avoid uneven pad deposits, you can avoid the thick pad deposits hitting your brake pads with every revolution, which will avoid 'uneven' formation of cementite. If you had cementite form 'evenly' accross the rotor it wouldn't really be much of a problem.

Also, you still haven't answered my question, why do you get your rotors turned as part of a normal brake job. It doesn't make any sense and completely contradicts everything you're talking about. Again, why do you get your brake rotors turned? Why do you get your brake rotors turned?

Because I was switching pads. I was putting in new pads. I've said this already, many times, when you asked me before. Part of putting in new pads means having a COMPLETELY even smooth rotor to contact these 'fresh' pads, so they can deposit THEIR pad material evenly across the surface of the rotor. If you don't turn your rotors, and expose fresh material, you're trying to use the existing deposited pad material from the OLD pad with the new pad, which could be incompatible. Also, the grooves in the surface of the rotor PREVENT an EVEN LAYER OF PAD DEPOSITS from occuring.

How do you not understand this?

I can only hope that you don't continue to ask me the same questions again and again and again. I've explained both situations already, and Carroll Smith explained it better than I could in his article.

[86AccordLxi]

Spot on. That's my understanding, as well (not that I'm certified or have a degree or something else).

Alex

edit: ultimately, though, the end result is mostly the same-- a rotor that is probably beyond turning.

Edit2: I've also heard from people that work at some parts store, though, that some of the new rotors they get are 'pre warped.' You put them on a flat surface and there's obvious hi/low spots. Like I mentioned, my autozone blanks are still going strong even after getting some real solid head into them.

[Kelvin]

Thank you. It's nice to know there are some people who are actually comprehending what I'm saying.

[2ndGenGuy]

You didn't read what I wrote, or what Carroll Smith wrote. It isn't BRAKING that causes it, it's UNEVEN PAD DEPOSITS. I'll talk you through it, one more time.
1. You install crappy pads with a low max operating temp.
2. You properly bed the pads, putting a smooth even layer of pad material on the rotor.
3. You are driving 'spiritedly' and get your brakes pretty hot, and come to a stop, or just slow down enough to transfer even more pad material 'unevenly'.
4. This 'uneven pad deposit' is thicker than the rest of the pad material on the rotor. Now, if this 'deposit' hits your pads on every revolution, it does NOT REQUIRE BRAKING TO CREATE HEAT. Driving on the freeway will lightly hit that 'thick' pad deposit on your existing pad with every revolution, creating MASSIVE amounts of heat in very localized regions of the rotor, right on the surface of the rotor, right under the pad material. It is this area that will create cementite.

Let me rephrase what you said, and see if this makes sense to you:

1. You install expensive pads with a high max operating temp.
2. You properly bed the pads, putting a smooth even layer of pad material on the rotor.
3. You are driving 'spiritedly' and get your brakes pretty hot, and come to a stop, or just slow down enough to transfer even more pad material 'unevenly'.
4. This 'uneven pad deposit' is thicker than the rest of the pad material on the rotor. Now, if this 'deposit' hits your pads on every revolution, it does NOT REQUIRE BRAKING TO CREATE HEAT. Driving on the freeway will lightly hit that 'thick' pad deposit on your existing pad with every revolution, creating MASSIVE amounts of heat in very localized regions of the rotor, right on the surface of the rotor, right under the pad material. It is this area that will create cementite.

Okay after reading that, what about a high-temp pad prevents it from leaving deposits? This is what I'm trying to ask you, and this is why it doesn't make any sense to me at all.

They will prevent it by preventing UNEVEN PAD DEPOSITS FROM OCCURING IN THE FIRST PLACE. If you can avoid uneven pad deposits, you can avoid the thick pad deposits hitting your brake pads with every revolution, which will avoid 'uneven' formation of cementite. If you had cementite form 'evenly' accross the rotor it wouldn't really be much of a problem.

Again, how do high-temp pads prevent uneven deposits? You're not making the logical connection. All you're saying is HIGH TEMP PADS PREVENT UNEVEN DEPOSITS. I disagree.

Because I was switching pads. I was putting in new pads. I've said this already, many times, when you asked me before. Part of putting in new pads means having a COMPLETELY even smooth rotor to contact these 'fresh' pads, so they can deposit THEIR pad material evenly across the surface of the rotor. If you don't turn your rotors, and expose fresh material, you're trying to use the existing deposited pad material from the OLD pad with the new pad, which could be incompatible. Also, the grooves in the surface of the rotor PREVENT an EVEN LAYER OF PAD DEPOSITS from occuring.
How do you not understand this?

How do I not understand this? Because this is the first time you've explained it without just saying "because I was switching pads" which is not a reason for turning rotors alone. And now you're saying that you have grooves in your rotor, which are radial around the rotor. How would this prevent an even layer of pad deposits laterally? If the grooves are evenly distributed laterally, and not wavy, I don't really see a problem. And if your case is correct, how do you know the grooves aren't already from uneven pad distribution????

The reason you have grooves, is because you're using some crazy semi-metallic pads and cheap rotors. This problem wouldn't be so bad if you used good rotors. Your chart shows the differences in the ways that metals are tempered, and shows that better iron compositions can improve wear resistance. Hence good rotors have higher wear resistance!

Thats why I kept arguing to use better rotors. You can either use cheap rotors and replace / resurface them often, or use good rotors and not replace / resurface them so often. But you began insulting me, saying I was spreading BS and to read the article. What is more practical for most people? Metallic pads and cheap rotors, or ceramic / organic pads and good rotors?

Now what's good for a person who is racing? Maybe cheap rotors and high-temp pads. Why? High temp pads prevent FADE and glazing. FADE is the major killer in your stopping ability. The temperatures on the rotors and pads are still the same if you had cheap components. Your brake fluid turns to shit, and can no longer apply the proper pressures to your pads to grab the rotors. The reason you can get away with cheap rotors is because the amount of brake wear is INSANE when you are racing, and just about ANY rotor will be destroyed at the end of a race unless you have some EXTREMELY expensive rotors. I'm talking 14 inch, 2-piece rotors with cooling holes CAST into the rotor.

To answer that question properly, go back to my argument that high-temp pads don't prevent uneven pad deposits. Now assuming this, which one would you logically have to suggest for people who don't race or the majority of the people in this forum with OEM-style brakes? The longer lasting solution, or the one that eats up rotors?

You keep insisting that EVERYTHING is cementite buildup. You keep saying that uneven pad material (which I agree can happen) can NEVER be burned off, and it always causes cementite. You keep saying that rotors CAN'T warp. I have NOT argued that cementite can't happen. I don't know for sure that it does, but you're 100% wrong that it is always the case. If it does indeed happen, I find it to be the least likely cause of brake shudder. Whether the brakes are warped, OR it's this supposed cementite, the symptoms are the same, and the rotors are toast and need to be replaced.

Go to Corvette forum, and talk to people who track day their cars. They get shudder, and FIX it by burning off and rebedding and heat cycling the rotors. It happens ALL THE TIME! People do it, and it works! If the rotors aren't toast, and trying a FREE, EASY solution helps BEFORE replacing the rotors, why not try it? Why pick apart my arguments in old threads and call me a bullshitter?

Thank you. It's nice to know there are some people who are actually comprehending what I'm saying.

Again, more of your arrogant attitude. Stick with facts.

[Kelvin]

You are completely hopeless. You can't even read correctly. That is the problem here. I CLEARLY stated in the first example that crappy pads with a LOW max operating temp are more likely to cause uneven pad deposits, because they require a much lower temperature to transfer pad material. Instead of reading this correctly, you read the opposite. You read 'expensive' instead of crappy. How? Who knows. All I know is that I'm done with you.

I give up on you. The brake lord has banished you from the land of the intelligent. He could respond to your other posts, but you've made it quite clear you're unable to understand simple paragraphs and examples correctly. I'm not sure if it's your brain, or your reading ability, but something 'just ain't right' in your comprehension abilities.

PS: I've had extremely aggressive pads on my car for 40,000 miles. Have not needed to replace a rotor or the pads yet. Have not had any pedal pulsation. At all. Always smooth. Always works great.