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



## G Jones (May 11, 2021)

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)


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## cathead (May 11, 2021)

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.


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## wrat (May 11, 2021)

This kinda throws me....



G Jones said:


> that hardens extremely well with little precision,


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.


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## Braeden P (May 11, 2021)

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


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## Janderso (May 11, 2021)

Considering todays prices on all building materials, venturing out into scrap yards or used car parts for steel sources may be the new normal.
I made a bushing the other day out of an automotive tie rod shaft. Worked great.


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## Larry$ (May 11, 2021)

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.


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## benmychree (May 11, 2021)

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,


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## mcostello (May 11, 2021)

I friction sawed a piece and the top half was dark like cast iron and the bottom was steel colored. Was not evenly mixed.


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## G Jones (May 11, 2021)

wrat said:


> This kinda throws me....
> 
> 
> Precision?
> ...


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 

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.


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## G Jones (May 11, 2021)

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.


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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## G Jones (May 11, 2021)

I still make 99% of my stuff out of 01 tool steel, and nothing will beat it for me, but, considering the fact that I do very small work mostly in brass and a little aluminum, the appeal of being able to make things like odd dovetails/ slot cutters quickly and easily, and pretty much entirely for free, has appeal.


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## Canus (May 12, 2021)

Auto coil springs would be your best bet for a material source.


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## G Jones (May 12, 2021)

Canus said:


> Auto coil springs would be your best bet for a material source.



yeah Ive used them before. definitely have to agree.


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## john.k (May 13, 2021)

There is a high tensile type of rebar,used especially as a long tierod to join large formwork together ......the knobs/bumps on it all spiral in one direction,and a sort of long nut can be screwed  on to tension the bar.........Its more or less as strong as a crowbar.....and I use the 1 1/4 " stuff for lifting machines with holes in the frame.


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## Karlito26 (May 19, 2021)

I have worked with rebar on the lathe. It was free and I was testing a concept. The big downer was it was coated in a type of plastic and I had a lot of cleanup.
But it machined well for what I needed to prove out.

Since we are talking about free metal; printers are a good source of round bar. Especially old printers and the Oki dot matrix ones.


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## ericc (May 19, 2021)

It depends on what the use is and what is being compared to.  I took a tong making lesson from a curmudgeon.  He had a somewhat unconventional way of teaching that probably ended up dating back to the middle ages.  He would not let students work on a forge that allowed bars to pass through.  When we asked how we could cut the tong blanks off the bar, he yelled "THINK"!  We complained that you couldn't heat the bar at the correct place to cut it, and he said "haven't you heard of convenience bends?" We complained that you couldn't bend the bar far enough up to get the cut location in the fire.  He replied, "are you limited to a single bend? THINK".  When it came time to punch the hole for the rivet, he wouldn't let us use his punches, since we might ruin them.  He also had no grade 5 bolts or O-1 tool steel.  We had to fish a piece of mild steel out of the scrap bin.  If you were not careful, the punch would get a kink at the business end that would be impossible to straighten out.  He would glance over and mutter that he was surprised that you were able to get a single use out of your lousy punch the way you were poorly managing the heat.  At the end of the lesson, I complained that it was a pretty unpleasant experience.  He said, you have learned some lessons that are much more important than your crappy tongs that you at least finished.  First, don't expect to be able to borrow tools, and second, pay attention to the different types of steel.  Remember your stumbling and humiliation every time you think that junk steel will suit your needs.  Too many beginner blacksmiths are enamored with mystery steel.  When I got home, I forged some hot work tools out of hardenable rebar.  They were so superior to mild steel.  I immediately ordered a sample pack of S-7 off Ebay.  It's one of the best hot work steels, but the jump in suitability from junk scrap to rebar was huge. Of course, I qualified the rebar with quench and break and spark tests.

For turning, rebar has too many inconvenient ridges.  Not appropriate use.


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## 9t8z28 (Jun 9, 2021)

I agree that rebar is usually not a good choice but certain structures such as bridges and tall building foundations require a specific grade of rebar (not 100% recycled steel from China) and depending on your needs may be the right material for you.  I know that you're not likely to come across this type of rebar at a scrap yard or job site because most of the time these high end jobs are gated and the scrap is sorted and recycled.  Also most rebar is stamped with a few numbers and letters that will tell you the manufacturer and the grade.  Grade 60 has more carbon than grade 40 and some rebar is actually a low to medium alloy.  Grade 60 has a minimum yield strength of 60,000 PSI and a minimum tensile strength of 90,000 PSI while grade 40 has a minimum yield strength of 40,000 PSI and a minimum tensile strength of 60,000 PSI.  To identify it you look at the numbers or characters between the lines or ribs.  Just do a quick google search using the keywords "what grade rebar is required for structural" or "identifying rebar".  That being said, I'm pretty sure your not going to go to Lowe's or your local supply chain and find this type of rebar but then again I have not really looked that far into it and I don't know that much about alloying elements to tell you which one is better


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## 9t8z28 (Jun 9, 2021)

Karlito26 said:


> I have worked with rebar on the lathe. It was free and I was testing a concept. The big downer was it was coated in a type of plastic and I had a lot of cleanup.
> But it machined well for what I needed to prove out.
> 
> Since we are talking about free metal; printers are a good source of round bar. Especially old printers and the Oki dot matrix ones.


I second this.  I have scrapped many printers, fax machines and copiers.  You can usually find the 200lb. commercial printer/fax combo machines on craigslist for free if your willing to remove them yourself.  I got a Zerox that had 8 different sections to it for free and after about 2 hours of disassembly I had three 5 gallon buckets full of ground rod from 2MM up to 20MM and coffee cans full of gears, motors, screws, springs, bearings, one way rollers, bushings, etc.


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