Rebar as a beautifully workable, easily hardenable steel??!

G

G Jones

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I've has a couple people recently claim that rebar makes for an absolutely effortlessly workable mild steel, that hardens extremely well with little precision, making for cheap and easily prototypable cutting tools for softer metals like brass and aluminum.

Do you guys have any other suggestions for neat tricks, great cheap hardenable steels, and poormans solutions to designing cutting tools suitable for softer metals?

Cheers!

(im looking forward to running over to the local construction site and steaing some rebar cutoffs (by stealing I mean offering a case of beer for a bucketful of cutoffs. (more than ill likely ever need)
 
Rebar is a variable commodity. It is not all the same. You may have good luck with it or maybe not.
It's not top tier metal by any means and commonly made of recycled scrap with various impurities.
A lot of rebar is imported these days so quite unidentifiable as to content. My feeling is that one is
better off using something that you have a pretty good idea as to what it is. Solid auto or truck axles
are generally pretty good material to machine. Leaf springs are high carbon steel and can be quite
useful if you want something hardenable. I would personally recommend a scrap yard over a construction
site for usable material any day. There is certainly nothing wrong with experimenting a bit with some
rebar as long as you know there may be variable results.
 
This kinda throws me....

G Jones said:
that hardens extremely well with little precision,
Click to expand...
Precision?
This almost indicates that if it doesn't harden, it's somehow the fault of the imprecise craftsman. I disagree.
There's no real carbon in re-bar. It's soft forever, no matter what heat cycle you throw at it.
Conceivably, if you desire (GREATLY desire), you could perhaps carburize re-bar. Perhaps. Case-hardening, as it were. Possibly with a little distortion.
I'm all for you having a stash of it. I always have some around. Like wrought iron, it's something to pound and bend on. Cheap and easy. But bringing it into any form of hardened state will be far more trouble than worth, if any specific piece can be done at all.
 
some rebar can be hardened but most has too low of a carbon content for easy to machine use 12L14 most places it is cheaper than 1018 and cuts easy as aluminum and chips from steel really nice to work with
 
Rebar comes in many grades, also in a "no grade" Chinese version. Architecturally specified jobs will normally "require" a certain grade based on the structural design that was used. Small jobs and especially residential work usually uses the cheapest available. I've used both kinds. The Chinese stuff is highly variable. It would sometimes bend like a limp noodle and sometimes snap when being bent.
 
Rebar is not tool steel or at least most of it is not even high carbon or alloy, it would be a waste of time and energy to mess with it. The only slightly similar thing that I did was to make some woodworking lathe tools out of model T Ford magneto magnets, they are a very fine grain carbon steel and may be forged to shape and re hardened and ground,
 
I friction sawed a piece and the top half was dark like cast iron and the bottom was steel colored. Was not evenly mixed.
 
wrat said:
This kinda throws me....


Precision?
This almost indicates that if it doesn't harden, it's somehow the fault of the imprecise craftsman. I disagree.
There's no real carbon in re-bar. It's soft forever, no matter what heat cycle you throw at it.
Conceivably, if you desire (GREATLY desire), you could perhaps carburize re-bar. Perhaps. Case-hardening, as it were. Possibly with a little distortion.
I'm all for you having a stash of it. I always have some around. Like wrought iron, it's something to pound and bend on. Cheap and easy. But bringing it into any form of hardened state will be far more trouble than worth, if any specific piece can be done at all.
Click to expand...
A friend of mine said he saw some videos on youtube, and by "hardening with little precision" I meant, like, following the blacksmith colour draw technique, as opposed to following temp guides and cooling patterns. Get it up to the right heat, quench in oil/water.

I'm actually surprised its not just a single type of cheap mild steel, but I guess that makes sense. Maybe he just had a batch with a bit more carbon content.

I agree about the scrapyard assessment. I happen to have spent a decade working in concrete and there are probably 4 build sites in town I could just walk onto at the end of the day where I know people who are working. I wouldn't suggest just raiding strange construction sites :D

anyways I'll do some quick experiments over the next little while and see how it goes, though, I do have a pretty full plate.

I will say I've personally seen a file skate over it pretty effortlessy after quenching. I didnt have HRC testing files around at the time.
 
Larry$ said:
Rebar comes in many grades, also in a "no grade" Chinese version. Architecturally specified jobs will normally "require" a certain grade based on the structural design that was used. Small jobs and especially residential work usually uses the cheapest available. I've used both kinds. The Chinese stuff is highly variable. It would sometimes bend like a limp noodle and sometimes snap when being bent.
Click to expand...
Ive never worked with chinese rebar!
I totally believe you though, I once saw a chinese drillbit that somehow UNRAVELLED.
I'm not an expert as I was a concrete forming carpenter, but im no stranger to working with the stuff. The bar we worked with came from a smaller local company, and was always super consistant.
 
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