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Been awhile since I was here. Last time we talked about an Peter Wright anvil I was given. Now I thought I would show you my first project. The main body is mild steel, then the handle I threaded this and put on a brass nut followed by a few stainless steel nuts and another brass nut. the last brass nut I threaded and put on a larger brass nut. I braised both ends and tig welded the SS nuts together. Overall length is 20 inches.

I am curious about harding mild steel, as this project was cut out of a 1/4 inch steel plate that I had laying around. I used 5W-30 motor oil. Good or bad? What would be best?

thanks again for sharing all your knowledge.

Bob

side 1.jpg

side 2.jpg

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Unfortunately mild steel does not harden. Not enough carbon in it. You would of had to forge weld in a piece of good hardening steel for the edge. The mild steel won't hold an edge. Other than that, it's a pretty cool 1st project. Good job 

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This will sound harsh, but:  Wow all that work for at most a mild steel kindling chopper for a fireplace. Part of why we do not suggest blades as an early project for smiths is that they don't know these details yet.  The concept of mild steel is that it won't harden. However you are not the first person who has asked about hardening a mild steel blade they have spent hours forging on here---probably not the 50th either.  The oil quench was just a useless waste of time, fuel and oil.  Now if it was A-36 you could get a bit more hardness out of using super quench; but still not keep an edge like you would want an axe to have.

Now if you cut the next one out of an old agricultural disk then you probably would have a steel that could be hardened appropriately (some of the newer disks are not suitable)---note: higher carbon steels have special forging requirements, (temperature ranges, watching out for overheating or contact quenching, etc---why you should know the basics and then add on the extras for blade forging)

 

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So you made something that ultimately won't totally work out because the steel you started with. Guess what? We've all made stuff that ultimately didn't work out even when we started with the proper steel. You managed to make something that looks pretty good and you learned some things in the process, so don't get discouraged. Hang that guy on the wall in the shop and have another go at it with some higher carbon steel. If using repurposed steel take a look at some of the threads on here about testing carbon level. There's the spark test method described in some threads. I've personally never gotten the hang of that, so I just take a small piece and sample harden it and try breaking it. Even a simpleton like me can tell a snap from a bend :) 

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  1. Thanks for all the feed back guys. I do think I will just hang it on the wall. What about coil spring steel? Leaf springs? Lawn mower blades? I have some of all those laying around.
  2. Harding, what to use works best? 5W-30 motor oil? Someone was telling me about a "receipt" that had salt, water, dawn dish soap and some other stuff mixed together. WHAT?? Any thoughts on what to use would be appreciated. I will work the next project out of better steel. 

Thanks again!!!

we think he means hardening, there are pinned sticky posts about heat treating, we suggest you read them

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Buzzkill   

Most coil springs and leaf springs will make decent blades.  It's still a good idea to test them first, since there are some out there that do not harden in an oil quench.  Lawn mower blades are less predictable.  Some will not harden at all and others harden quite well.  Again, you'll want to do a test piece before putting in a lot of time and effort on a blade.

We generally recommend against used motor oil due to the contaminants that tend to be in it. Unused motor oil is probably not too bad, but is expensive compared to several other alternatives. Canola oil, peanut oil, vegetable oil, or even used fryer oil are safer for you and work ok.  The recipe you are referring to is called "Superquench" and is normally used for steels that barely have enough carbon to harden.  It provides a very fast quench and would likely cause cracks in a lot of the simple high carbon steels at knife blade thickness.

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Do you have the recipe for this superquench? and would this work on mild steel?

Next question is testing the steel. I have looked over here and there for the test. I know there is a grinding test and breaking test. The grinding/spark test to me seems a bit difficult to tell just by looking at sparks unless you have a good eye and lots of experience. the breaking test seems the way to go for me. To quote Lanternnate:  "Even a simpleton like me can tell a snap from a bend." I am sure I can tell that to.

Thanks again for all the help and advice, and when the project #2 is finished, I will post a picture.

Bob

 

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Nice axe,

looks like you enjoyed making it. Am new to this myself. But you could forge weld at some point a bit made from carbon steel into a purposely cut slot at the cutting part. Is very difficult to pull of but then you will be able to harden it me thinks. 

David. 

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Buzzkill   
On 9/2/2017 at 10:10 AM, Bob Cofer said:

Do you have the recipe for this superquench? and would this work on mild steel?

Recipe:

5 gallons water
5 pounds table salt
28 ounces BLUE Dawn dish detergent
8 ounces of Jet Dry or equivalent.

I haven't tried it on anything, so I have no personal experience as to what can be hardened using it. As I understand it, there is a threshold for carbon content below which the steel will not harden regardless of the quench medium, but I'm not sure exactly where that point is.

if you read the HT sticky , then you would know

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Don't hang it on a wall, you can still use it for splitting small firewood by using a mallet on the backside. 

Mower blades are hit and miss because some are a boron based steel that takes a special heat treating to get the best out of it. 

 

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On 9/2/2017 at 10:10 AM, Bob Cofer said:

Do you have the recipe for this superquench? and would this work on mild steel?

Next question is testing the steel. I have looked over here and there for the test. I know there is a grinding test and breaking test. The grinding/spark test to me seems a bit difficult to tell just by looking at sparks unless you have a good eye and lots of experience. the breaking test seems the way to go for me. To quote Lanternnate:  "Even a simpleton like me can tell a snap from a bend." I am sure I can tell that to.

Thanks again for all the help and advice, and when the project #2 is finished, I will post a picture.

Don't bother trying to harden mild steel. Lanternnate was referring to hardenable steel....if its hardenable, once quenched, it can be snapped instead of bent. It will be brittle like plate glass.

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OK first do you really want *best* even if it' costs tens of thousands of dollars?   "Best" is a useless term unless you add in all the details like "cheap, easy to find, Can be used without fancy equipment, is legal in my country, etc.  My standard example is:  I need to buy a vehicle; what is the *BEST* one for me to buy?  Now I am not going to tell you if it needs to haul 16 people at a time or 16 tons of coal, whether it needs to be cheap to drive 200 miles a day or has to haul a house trailer, whether it has to be able to cross rivers, an ocean or make it to the international space station;  So What is the BEST vehicle for me? And I will be upset if you can't give me a correct answer!!!!!

BTAIM may the proper quenchant for a specific alloy may be different depending on that alloy: Water, Brine, Oil, Air are the basic old quenchants.  If your coil and leaf springs are 5160 or 9260 they should do well in warmed vegetable oil---around 110 to 140 deg F and you need enough oil so that the blade does not heat the oil past tempering temperature OR IGNITION POINT!!!!!

If you do not know the alloy you generally start with a mild quenchant like oil and test to see if it hardened correctly (watch out for decarbed surface layers!).  If oil didn't work try brine or water.  Knowing that moving to a harsher quench may result in the blade breaking during quenching. ALSO TEMPER IMMEDIATELY AFTER HARDENING!

Super quench: is for A-36 steels that you want to make a touch harder or tougher IT WILL NOT TURN A MILD STEEL (OR EVEN A-36) INTO A PROPER HARDNESS FOR A GOOD KNIFE EDGE. 

Not that all this info has been posted here many many times before; may I commend to your attention the stickies in the knife section that covers alloys and heat treating?

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Thank you very much. I think it looks good too.

The balance is nice and comfortable. The brass and SS nuts makes it a heavy piece. But I like the way it looks and feels in my hand. I am looking at forge welding videos on u tube and might find so high carbon steel to forge weld to the blade or the head of the ax. I don't know yet. I am going to learn to forge weld, that is my next goal. Then hardening steel. After I get a good grasp on those two, project # 2 will follow.

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Where is the balance point on that piece? Axes generally tend to balance forward for chopping.  As I mentioned it would make a good display kindling splitter; though I might forge out the spike a bit and curl it around to make an eye to hang it from on the fireplace tools rack.

May I commend to your attention "Step by Step Knifemaking" by David Boye  he shows a lot of blades cut out of high carbon scrap stock and how to work them up.

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Buzzkill   
On 9/2/2017 at 10:43 AM, Buzzkill said:

 

I haven't tried it on anything, so I have no personal experience as to what can be hardened using it. As I understand it, there is a threshold for carbon content below which the steel will not harden regardless of the quench medium, but I'm not sure exactly where that point is.

if you read the HT sticky , then you would know

I must have missed it the last 5 or 6 times I read the heat treating stickies in addition to the recent review this comment prompted. If it's there I missed it again which could mean I need to slow down and read more carefully, but it might also be an indication that it's worth repeating occasionally for the benefit of others.

This is the closest thing I found, which is a different way of saying what I said:

"Physics states if there is not enough carbon present, as in mild steel, to form martensite in an appreciable amount of the steel matrix, then no amount of super quench can change that, simpler to use correct steel for the application."

While it is clear that mild steel is not a good choice for blades, what is not clear is the cutoff point for steels with regard to carbon content where some hardening benefit may be obtained by using something like superquench.  As mentioned here and other places, steels like A36, definitely considered a mild steel, can gain some increased hardness.  It's still not a good choice for a blade of course, but the OP put in a lot of time and effort and is trying to make the best out of what he did. 

I guess my question would be, "What's the down side of trying it?"   The work is already done.  I'm sure he'll use a more suitable steel the next time around, but can he make his axe shaped object slightly better through the use of superquench?

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Depends on the carbon content of the A-36; but as you mentioned it can't hurt.  I'd do an edge heat and edge quench so as to not mess up the rest of the blade.  Or he could use the time, money and effort making the next one out of better steel.  If he's wanting to do blades having a bunch of superquench around isn't  much of a help and is an attractive nuisance---(the temptation to quench a higher carbon steel in it as it's handy resulting in multiple pieces...)

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On 9/4/2017 at 8:24 AM, ThomasPowers said:

Where is the balance point on that piece? Axes generally tend to balance forward for chopping.  

The balance point is about 1-1/2 inches above the handle.

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I find that leaf springs harden nicely in veggie oil. No toxic fumes. Buzz down to Sam's or GFS and buy a 5 gallon bucket of it. It'll go bad after a while, but I'd rather quench in Veggie oil than toxic-fuming stuff. Great work on your first project. Keep on forging, Bob! 

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Will W.   

I don't think it going bad will have any effect on its ability as a quenchant though. You just wouldn't want to cook your fries in it (which I wouldn't recommend even if it's non spoiled quenching oil lol.)

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of course the smell of glowing steel hitting rancid oil tends to attract neighbors with pitchforks and torches not to mention incurring the wrath of any SO's!

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Not when they are chasing you---or the SO is glaring at you and telling you to burn your clothing and run yourself through the car wash several times...

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Will W.   
30 minutes ago, ThomasPowers said:

of course the smell of glowing steel hitting rancid oil tends to attract neighbors with pitchforks and torches not to mention incurring the wrath of any SO's!

Now that sounds like a man speaking from experience. Lol. 

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