Tempering schedule for digging knife

fast14riot

fast14riot

Joined
Oct 27, 2010
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I'm curious what you guys consider a good temper target for a 1084 digging knife. It will be used very roughly, prying, hacking, one side will be serrated for cutting roots, etc. Will be roughly 7" blade and 1/8" thick by 1.5" wide. I was thinking somewhere around 500*F for a target of 55-56 hRc.


-Xander
 
That's about what I was thinking... You'd rather it rolls than chips. 54 puts it in Axe territory - which feels right to me for hard use.
 
I make, test and use a lot of blades that get abused by conventional knife-use standards. Tempering differs with the choice of steel. 1084 would hold up well at 54-56HRC but you really have to get out there and use it to know for sure. I suggest you start out around 58-60HRC and play with the grind. You'd be surprised at what the steel can take. Geometry plays a HUGE role with blades like these.
 
Yeah, Rick, I agree that geometry is a bigger factor for ultimate strength and I have it pretty much figured out. It will be scandi-chisel grind on both edges, the whole blade will be forged to a large shallow radius (kinda like a trowel) and a blunt leaf shape. It will be kept sharp by a file, but nowhere near "knife sharp" because of rocks, dirt, roots, etc will dull it and going to a more obtuse edge geometry will suffice.

Good thinking starting at a little higher temp and testing.


-X
 
Draw your own conclusions, but I found scandi grinds to be among the worst for this type of use. Think of a regular garden shovel. They are rather thin... even compared to most of the knives I've seen from the "hard use" camp. Yet, they still dig all day in rocks and roots. What I would want is a sharp shovel, so to speak. The cross section you are talking about will assist with rigidity... I believe you can get away with a much thinner knife that you think. Shallow convex/flat grinds with a primary v-edge or serrated is hard to beat in my experience. It sounds like you'll be testing away at it, though... have fun, bud! Post PICS!
 
I've managed to bend, break and deform most trowels out there, hence the need for something a bit more stout. Its not going to be a true scandi grind, but just a short one.

This is one of the better digging tools on the market, I've used them and they are good, but I don't feel like paying $50 for one when I can make one for <$20 in materials... this will be the type of grind I will use, it is chisel ground.

(Not my pic, pulled from the web)
DSC02352.JPG


But, like you said, I will be testing it hard!


-X
 
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