WAGONJON Posted September 4, 2021 Share Posted September 4, 2021 Quick question: what does it refer to when "drawing the spine back?" Quote Link to comment Share on other sites More sharing options...
Frazer Posted September 4, 2021 Share Posted September 4, 2021 The only context relevant to knife making where I hear that term is with respect to tempering. Drawing the spine back as in tempering the whole knife and then further drawing the hardness out of the just the spine. This differential tempering retains the knife's ability to hold an edge while allowing it to bend/flex with less risk of breaking. The easiest way to do it is to submerge the edge in water and pass a torch over the spine. Out of curiosity in what context did you hear the term? What kind of knife are you trying to make? I'm making some assumptions because the way you phrased your question provides no background... Without context "drawing the spine back" can mean different things to different people.. Quote Link to comment Share on other sites More sharing options...
WAGONJON Posted September 5, 2021 Author Share Posted September 5, 2021 Frazer, this was in reference to a post I made on another platform (IG) where we were talking about 8670 steel and its ability to be a tough working knife steel. The kind of knife I'm trying to make is a common bushcraft knife with the ability to withstand batoning and retain utilitarian qualities. Lots of info out there, I realize that. I've found some carbon steels are more prone to chipping than others and am researching carbon steels that are less prone to edge failure. Of course quenching and tempering have a lot to do with it, that is understood. Just gathering information at this time. 1080,1084 are tough steels also. Differential tempering does help to keep a knife more resilient to breaking as you mentioned above. Just was curious about "drawing the edge back" as I have not stumbled across that phrase before. Thank you for your response. Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 5, 2021 Share Posted September 5, 2021 4 hours ago, WAGONJON said: "drawing the edge back" I would have to take that statement as a typo. I'd like to know what material or use would require the edge be drawn back. I've never heard of such, then again I'm not a bladesmith guy. Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
WAGONJON Posted September 6, 2021 Author Share Posted September 6, 2021 Supposed to say spine Quote Link to comment Share on other sites More sharing options...
Frosty Posted September 6, 2021 Share Posted September 6, 2021 Oh well. Try to make typos I can have more fun with will ya? Frosty The Lucky. Quote Link to comment Share on other sites More sharing options...
ThomasPowers Posted September 7, 2021 Share Posted September 7, 2021 I picked up a set of tempering tongs used to draw the temper of the spine. Tongs with a cross bar welded to each bit. To use you heat the cross bars in the forge and then "grab" the spine of the hardened blade and so soak the heat in from the spine. Some folks also just heat a slab of steel and set the spine of the blade on that. Keeping an eye on it so you don't over temper the edge is important. Differential hardening and differential tempering are a couple of techniques that can help make handmade blades better than commercial ones. Quote Link to comment Share on other sites More sharing options...
anvil Posted September 7, 2021 Share Posted September 7, 2021 I built a set similar to that but found a better way for me. With a coal forge and a 3"-4" deep firepot, with fire control and a very low air flow from your blower, you can build and easily control a very narrow fire, say half to an inch wide. Polish your blade so you can see the colors run and place the spine onto the narrow fire. Watch the colors run, and with a rag or cotton balls to apply a little water, you can control the speed the colors run towards the cutting edge. With a bit of practice you can get pretty nearly a dead soft(or whatever you want) spine, a spring temper in the center of your blade, including the transition of the knife to tang, and a nice straw color on the edge. Pay particular attention to not screw up the tip. Quote Link to comment Share on other sites More sharing options...
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