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  1. #1
    Join Date
    Nov 2020
    Location
    Belgium
    Posts
    6

    Default Add carbon to mild steel (how to harden)

    Heya everyone,

    I'm new to the forum and this topic might not be on the right section. Apologies for that.

    It's been few years now I've been tempted to make/buy some japanese Kanna planes.
    However, due to the pandemic situation, buying is not an option atm.

    I then started thinking of how to make my own. The body part of the kanna plane wouldn't be an issue but the blade... I've checked for options to buy online... they are so damn expensive.
    I then thought of using the blade from my "eu" style planes. Have 100's of them but it won't work (this is just an assumption) because too thin.
    I thought then of making a blade myself but impossible to find some high carbon material. Thought of leaf springs... can't find nowhere in my country...
    Last option, use a piece of mild steeel and add carbon to it... to make it more durable (especially the bevel).
    One of the techniques I found is the one used on the youtube channel ClickSpring. Basically it involves a "paste" of grinded leather charcoal, water and flour. The steel is wrapped up in it. Let it dry then wrap it up in clay.
    Next step is to heat it up for a given amount of time.

    I've never tried this method but seeing the result of ClickSpring it looks promising. I have however one major question (actually 2) : do you think that this process does work with any kind of mild steel ? Is there any other method allowing to increase the % of carbon ?

    If I'm not mistaken, I should complement the process by quenching and tempering the metal which will be a necessity to get the hardening results I'm looking for. But clearly this won't work on a low carbon % steel.

    Thanks a lot for any piece of advice.

    Cheers

  2. #2
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    5,526

    Default

    Gday Xhinsy
    Well your are in luck then. You have arrived in a forum where there are more that a few that make their own planes.

    No doubt these blokes will login soon and answer. In fact you should see a page header above offering a challenge to build a woodworking plane.

    A heads up for you regarding the moderation of new posts.

    New members are usually auto moderated over the first 10 posts that can require lifting of moderation by an admin person if a pic or link is posted.
    Sometimes the auto moderation works and sometimes it doesn't. If you have trouble, please PM me and I can fix it. Its all about forum security and preventing spam.

    Usually it is the moderator who OK's the post and it can then be seen by all.

    Back to hardening your steel.

    The type or hardening to plain mild would apply to the surface of the steel only to a few parts of a millimeter depth and may not be at all suitable to a cutting edge as this would be lost each time the edge is sharpened.

    To have hardness right through, the steel need to have a 0.7% to 0.9% (and sometimes higher) carbon content to allow the needed transformation change need for all through hardness. By comparison mild steel runs about .3% carbon.

    However I don't make plane blades but the blokes who do will be along shortly.

    If you look up Derek Cohen on our sister woodwork forum, he is one that has a number of posts on the subject. He does post here on the MetalWork side but not too often.

    Cheers

    Grahame

  3. #3
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    5,526

    Default

    Hi Xhinsy,
    The plane makers haven't clocked in yet.

    I remember seeing a U tube about a cheap diy plane blade. It took a while but I found it.

    The presenter describes what is required in terms of carbon content pretty well and cheap source of the a perhaps suitable blade.You would need to test . I suspect the lawn edger blade would be tough but not hold an an edge.As he said its something that needs testing.


    https://www.youtube.com/watch?v=EHKu8v686VM.

    If the edger blade did not work I would be inclined to chase up an old cleaver maybe at the second hand markets if you are not still locked down.
    It will be around the correct hardness and you should be able to cut it to your dimensions using a angle grinder with a thin cutting disc, if you don't get it too hot.

    I hope that some of the above might be of use to you.

    cheers
    Grahame

  4. #4
    Join Date
    Nov 2020
    Location
    Belgium
    Posts
    6

    Default

    Heya Grahame,

    Thanks a lot for those useful tips and information. Now, the old cleaver is something I havenít thought of and I probably have around 10 of them (I love restoring things so Iíve build up a stock of old things). Itís a very good idea. I will definitely give it a try and why not take up the ďplane buildĒ challenge.

    I will make sure when cutting it with the angle grinder not to heat it up too much and ruin the tempering.

    Iíll give an update on that.

    If there are still suggestions about how to add cabin, Iím still interested in it, for my own culture.

    Cheers

  5. #5
    Join Date
    Nov 2020
    Location
    Belgium
    Posts
    6

    Default

    Oh, and by the way I watched the video of Rex Krueger, very useful. Helps understanding lots of things.

  6. #6
    Join Date
    Feb 2009
    Location
    Tasmania
    Posts
    41

    Default

    Hi Xhinsy,
    I wouldn't recommend case hardening mild steel for a blade. As Grahame mentioned, the hard part of the steel would be very, very thin and probably gone with the first sharpen. Something like 5160, which is generally used to make automotive springs, makes pretty good blades. There's other stuff with more chrome in it that would have slightly better corrosion resistance right up to full blown stainless steel - then you have more problems dealing with work hardening etc. Car, truck and trailer springs can be used to make great chisels, axes, plane blades, marking knives and heat treated without special equipment to suit the too you make - wait till your wife goes out and use the oven to temper your creation. I've hardened chisels using a butane torch and a couple of old bricks to hold and reflect the heat - you only have to harden the first 20mm that cuts, not the whole tool.

    As far as getting 5160 or some other spring steel, it can be hard to find in a specific size some times from steel suppliers, but I recommend a trip to the local tip or scrap yard to find some old discarded springs or even your local mechanic might have a couple of sets ready to be fished out of his rubbish bin. Don't overlook coil springs either. They are made from the same family of spring steel and will work well and as long as you have a way to heat a section up enough to straighten it and blacksmith it into the flat or curved shape you want

    I might get flamed for this, but in sheer desperation, the right variety of re-bar with enough carbon in it will make a blade, not a fantastic one, but certainly a blade that will hold an edge better than case hardened mild steel. Grahame's suggestion of lawn edger blades, or mower blades, especially ride-on mower blades as they are bigger, would work really well for your intended purpose. Probably get some for nothing from out the back of the local mower shop. I think they are 1080 series steels - 1080/1084 etc - and you can treat it like 5160. Either way, they will make good blades when hardened and tempered.

    I hope this helps a bit.

    Simon

  7. #7
    Join Date
    Nov 2020
    Location
    Belgium
    Posts
    6

    Default

    Hi Simon,

    Thanks for the explanation and suggestions.
    I dismissed the idea of case hardening.

    I think I'll give it a try to the solution suggested by Grahame, meaning the old cleaver. The only thing I hope is that it will hold the edge as I am wanting it to do.
    I tried with a file and it has a a very strong bite on the metal (cant tell the difference with a mild still). Maybe the cleaver hasn't been hardened as it should have? Duno.

    I've already been in 4 scrap yards, can't find a signle piece of leaf spring.

    The last option, if the old cleaver does not fulfill its purpose, I'll go with the lawn edger blade

    Cheers

  8. #8
    Join Date
    May 2020
    Location
    Willowbank QLD
    Posts
    67

    Default

    Out of curiosity I put in leaf spring works Belgium and come up with some results. This was the first https://www.weweler.eu/en
    Not knowing which part of Belgium you are in means it might not be close. When I was young Dad would get broken leaf spring parts from the local spring works to use for various jobs on the farm.

    Steve

  9. #9
    Join Date
    Nov 2020
    Location
    Belgium
    Posts
    6

    Default

    Hi Steve,
    Thanks for the info
    I think it's for B2B and we're not talking about scraps anymore.
    I can find new leafsprings to buy online but the price is quite high (around 100Ä) which at this point I can't afford.

  10. #10
    Join Date
    Jan 2004
    Location
    Mackay North Qld
    Posts
    5,526

    Default

    Hi Xhinsy,
    Another source of the blade steel would be the Knife making supply places. If you search online I am almost positive you find such a place in or near your country.

    We have those places in Australia and they not only can supply the stock but instruct you on how to heat treat and quench.

    Obviously the freight will be better buying local from your area.


    Here is an example of what a local Aussie knife supplies has if your search for 5160 ,1075 or or 1084( 38mm x 3.2mm x 1000 ) these are hard enough. These are simple to to heat and quench. Other grades are more difficult and if the above will do the job,it is probably better to keep it it simple.

    https://creativeman.com.au/steel/


    They will be sold annealed, that is soft, then you can cut , shape and drill until your hearts content.

    There is plenty of info online on making your on simple furnace though some knife making supply shops might be able to do that for you. I imagine that similar dimension would apply to what steel is for sale in Europe.

    The sites should supply dimensions of raw stock available.

    good luck

    Grahame

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