Le-Stan

AT (!) Ridgeway Forge Studio, thanks for your input! Didn't know at all that it was possible to figure out when the cracks occured... I'll first copy the design (that kind of came by accident but that I really like), then (try to?) break the blade and see what's inside Tempering started about 1/2h after quenching, so I hope the timing is OK Mike: Next time I'll quit messing around and quench it fully,... Didn't think that as "advanced", otherwise I wouldn't have done it, since I'm definitely not an "advanced" knife maker. Quite the opposite

Ouch, sorry, didn't know about that... Most forums allow that, but I'll avoid it in the future

@Mike BR the idea of quenching only the cutting edge (be it good or bad...) was to put less thermal stress on the upper part of the blade and hope that - being straight - it would keep the whole thing to go banana. In a way, it seems to have worked (the blade is straight after all...). I obviously don't know if quenching the whole blade would have made it curl or not. @Frosty I did heat treat before finishing grinding, but maybe I should have left more material. I had a look at what the "ideal thickness" is, but found a lot of different answers to that question... You don't want to start grinding (without overheating) a huge hardened chunk of metal either, so I still don't know how thick "forging it thick" actually is...

As you guessed, it was a "mystery steel"... Probably not the best idea, but I used what was at hand. Next time I'll use a leaf spring from a car suspension... So i won't be sure about the exact alloy either, but it looks like a very good advice to use offcuts as samples to test heat treatment for that specific alloy AND to go for less aggressive quenching mediums. Especially since I'm pretty sure my first successful attempt won't end up being the most used knife around the house, so it doesn't need to be insanely hard... @Rojo Pedro: I also think the shape was pretty cool and since I only noticed the cracks after starting to grind again, I really thought I was going to end up with a splendid knife (and it was even straight !), but it turns out beginner's luck only brings you so far... Thank you very much for this precious advice,... I'll make sure I share my next failure in this topic (if it's not closed by then) Stan

Hi, I'm not entirely sure this is the right place for this kind of discussion, but I'll post anyway. Please relocate if necessary, then forgive me ;). Oh, wait, let's first introduce myself a bit ! I'm Stan, DIY enthusiast and woodworker from Belgium. I like most things involving creating beautiful objects and experimenting with new techniques. Last Sunday, I was invited by a friend to try and forge a knife in his workshop. Exactly the kind of things I love. What could possibly go wrong? Well, I had a wonderful day, but ended up with a bit of a disappointing result (to say the least). To be honest, failure didn't really come as a surprise (when you forge your first knife, it's pretty rare to end up with something incredible...) but I wasn't expecting what I got: A blade full of cracks. Since I'd like to give it another go but without repeating the mistake(s) I made at the first attempt, I come here looking for an explanation about what actually went wrong... I'll detail the process hereunder: 1. I started with a cylindrical piece of metal that used to be part of a stone chisel, quite hard. 2. I forged it (gas forge - part drop forge hammer, part hammer) until I ended up with a flat piece of metal about 4-5mm (0.2 - 0.15 inches) thick. 3. I used a angle grinder to cut the shape of the blade (13cm/5 inches long + 13cm/5 inches handle), then a backstand to grind it until it completely flat on both sides, and I started to give it a very light bevel, which left me with 2.8mm/0.11 inches at the spine, 2.1 mm/0.08 inches at the - future - cutting edge). 4. Hoping not to end up with a banana blade, I put it back in the forge and quenched only the cutting edge (dropping about half the width of the blade held horizontally in water). 5. I tempered it in a kitchen oven (205°C - °F) for 1,5 hours 6. I started grinding again (being very careful not to overheat the blade this time)... until I realized the blade was completely cracked. 7. I cried 8. (Now) I'm looking for answers I hope one of you (after having had a good laugh at the idiot belgian who tought he would get away with this nonsense) will be able to give me the reason why things went that way and what I should do to avoid such catastrophic failure in my next attempt. Thanks in advance, Stan