hey guys i made a couple of knives out of 1084, but i did something wrong and the last two were too soft. i made some before with pretty much the same process, same quenchent (veg oil) doing an edge quench and they were fine. the problem is that im not sure what contributes to the hardness of a blade other than a faster quenchant and a different temp or shorter oven temper. did i not get the blades hot enough? was the oil not warm enough? too warm? please help!
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Knife to soft
- Thread starter dalr753
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We can't tell you without more information. Please let us know what temp you heat it up to pre-quench, what temp the oil is, and what temp you temper at. That will help a lot.
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With 1084, making sure the entire knife is non magnetic is where you want to be when you quench. Temper at 375 or 400 degrees for two hours, twice. Get something large and heavy like a cast iron skilet and put it in your oven to help add thermal mass and even out the temperature swings from cycling. A good thermometer in the oven is crucial to know what temp it is actually in there. After tempering you need to grind the thin layer of decarb off, this is soft and will be a few thousanths thick.
What exactly is soft on your knife? Is the edge not holding? Could be many things, but a rundown of what you did will help us, help you.
-Xander
What exactly is soft on your knife? Is the edge not holding? Could be many things, but a rundown of what you did will help us, help you.
-Xander
Stacy E. Apelt - Bladesmith
ilmarinen - MODERATOR
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There are several places where it could have gone wrong.
Edge Quench - Unless done exactly right, the heat in the un-quenched part will un-do the hardening of the edge. Plenty of folks love an edge quench, but I am not one of them. If you want a hard edge and softer spine, do a full quench, and then draw the spine softer after tempering.
Heating Method and Temps - The blade must be evenly heated to about 100 degrees above non-magnetic ( sorry fast14riot, non-magnetic won't be enough). Heat until the magnet won't stick, and then a little bit redder. For 1084 the temp is 1500°F. The more controlled the heat source the better. A torch will work, but a forge or HT oven is far better. Doing HT by eye with a torch is a skill that takes a long time to master ( and even then has failures).
Oil - The oil should be a commercial quenchant or fairly new canola. Other oils aren't usually suitable. Heat canola to about 100F.
Temper - The blade should be tempered twice at around 400F. Make sure the oven does not overheat, as some toaster ovens do.
Edge Quench - Unless done exactly right, the heat in the un-quenched part will un-do the hardening of the edge. Plenty of folks love an edge quench, but I am not one of them. If you want a hard edge and softer spine, do a full quench, and then draw the spine softer after tempering.
Heating Method and Temps - The blade must be evenly heated to about 100 degrees above non-magnetic ( sorry fast14riot, non-magnetic won't be enough). Heat until the magnet won't stick, and then a little bit redder. For 1084 the temp is 1500°F. The more controlled the heat source the better. A torch will work, but a forge or HT oven is far better. Doing HT by eye with a torch is a skill that takes a long time to master ( and even then has failures).
Oil - The oil should be a commercial quenchant or fairly new canola. Other oils aren't usually suitable. Heat canola to about 100F.
Temper - The blade should be tempered twice at around 400F. Make sure the oven does not overheat, as some toaster ovens do.
Last edited:
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Yep, sorry I forgot to note that a little above non-magnetic is needed. I assumed a 2BF or similar for HT which is easy to get that little bit more when just checking for non-magnetic. I was trying to imply checking the entire knife for temperature rather than just the thinner edge section.
-Xander
-Xander
