Mercedes-Benz Break Rotor?

S

Soviet Knifeist

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Feb 16, 2018
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Priviet!

Recently I acquired original 1984 Mercedes-Benz front break rotor. My thinking is that it is tough to withstand the usage, and given that it is old age steel should be good right? Good for knife?

Depending on how you give me answers I have two plans;

1. Cut it with acetylene torch, stick in forge to normalize, pound flat on anvil, stock removal to form, heat in forge normalize 3 times, put in canola oil, bake in oven for 204 C. to harden.

2. Make it brittle, break it with hammer, stack like Japanese to make Katana sword, hammer until high carbon steel, form bar, stock removal, same harden process.

Spaciba to you,
SK.
 
Most brake rotors are made of cast iron, which to my knowledge is not forgeable. I could be wrong though. I am sure some research may provide some additional insight.
 
Siety338 said:
Most brake rotors are made of cast iron, which to my knowledge is not forgeable. I could be wrong though. I am sure some research may provide some additional insight.
Click to expand...

I've looked to this... Information is found lacking. German secrets? XD
Though isn't Japanese katana made from basically cast iron? Pounded over and over to make High Carbon?
 
You could be right I really am not sure. Somebody who knows more about Japanese swordsmithing will be able to provide more information.
 
Why beat yourself up for no reason and possibly (most likely) poor results.
Just buy good knife steel and some more mild steel it you want to got the full traditional route and end with as fine a product as possible.
 
Looking in a copy of Machinery's Handbook from 1992
https://www.amazon.com/Machinerys-H...18845022&sr=8-5&keywords=machinery's+handbook

under General Applications of SAE steel I found no reference to steel being used in brake rotors.
So it is probably cast iron.
The closest I found was for transmission clutch discs which can be : 1060, 1070 and 1085.
Here is one to look at :Leaf springs 1085 and 1095 among many in the 4000 series, 9000 series and 6000 series.

True this is for SAE but probably not too different for Mercedies.
 
Brake disks for virtually all cars are cast iron. By a skilled guy, Its forgable to a limited degree. But considering the original question wording, on a limb I say that skilled guy is not you.
Its possible to torch cut and grind a knife shape object from it & no matter what you do to heat treat it, when finished you could break it in half with your fingers.

You will do much better making a knife from a coil spring or swaybar from that ’84 Mercedes.
 
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Soviet Knifeist said:
I've looked to this... Information is found lacking. German secrets? XD
Though isn't Japanese katana made from basically cast iron? Pounded over and over to make High Carbon?
Click to expand...
Well , problem is that in this case you must LOWER carbon content :D
https://en.wikipedia.org/wiki/Cast_iron
It is cast iron my friend ................maybe you can try something with disc from motorbike , they are some kind of steel ...............stainlees one .Well no good too , most are from SUS 410 .But I m 100 % sure that plate in automatic transmission gearbox is carbon steel .
I wonder what will happen with carbon if we MELT cast iron?
PS.Bolts class 10.9 and class 12.9 a alloy steel ;)
 
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Ok, the short answer is it is a very bad idea. I give an untrained smith 0% chance of it working.
The brake disc is cast iron ( I own a Mercedes).

Now, as to your description of making Japanese tamahagane. that is like describing open heart surgery as, "You just make a few cuts and stick in a new valve. Nothing to it!" The process is one taught over many years, and requires not just the cast iron part of the bloom, but the low carbon part. The knowledgeable smith will sort these and stack them as he sees right. Then the lesser skilled smiths will do then do the hammering and folding to unify the mix and create tamahagane. Any error or improper mix yields junk steel.

You didn't give any info in your profile, buy I will guess that you are in the Soviet area. Steel is available pretty much everywhere today. Buy a bar of O-1, 5160, 1085, 9260, etc. They are sold under the different numbers/names in some parts of the world (SAE, DIN, BS, IS, EN, etc.), but the numbers are referenced to the steel type in charts, so picking a steel should be easy.

Now, if you are set on repurposing that old Benz, use the leaf springs. They should be something similar to 5160 or 9260. They will forge out to make usable knives.
 
Stacy , I hope you didn't take your M-B and try! M-B truck springs were made of a 5160 Mod which in Africa they always looked for to make blades .
 
Beamers make excellent stake knives. Benzes not so much. Caddys are good outdoor knives. Ford and Chevy, don't waste your time.
 
Amazing information!!! Thank you to all of you people, I apologize for stupidity, I'm yet learning to make knives. I will go to look on Mercedes leaf spring. I very much appreciate all information you give me.

~SK
 
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