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The Newbies Arena Are you new to knife making? Here is all the help you will need. |
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#1
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edge knicked
my son made a bowie stock removal. 1095 stock, after heat treat he took it camping for the weekend chopped on some trees with it for fire wood and had some nails in it. any way the edge of the blade has a huge nick in it. what did I do wrong???????? it was edge quenched in veg oil and tempered at 375 in a oven. is the edge to hard or soft or what?? please help. Jae
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#2
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Hi Jae.
Could it be a combination of your tempering and edge profile? I tend to temper 1095 at 400F...but some may temper higher or lower....but thats what seems to work with me...so maybe 375 on your knife left the edge a bit too hard? Edge profile is important as well. What sort of grind is on the knife you made? A hollow grind, although gives a very sharp edge, may be a bit too weak for heavier chores like chopping wood (thin cross section?)...and if the temper was a bit to hard, then it is more likely to chip. A convex edge/grind should give more strength to the cutting edge (thicker cross section).... Just my 2 cents worth. Kevin. __________________ Kevin Davey Last edited by Coutel; 07-31-2004 at 09:31 AM. |
#3
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Even if your HT was perfect, whacking a knife edge into a nail will put a nick in it.
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#4
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I ground a convex edge on it. I have seen videos where they clamp a blade edge up and take round stock, lay it on the edge and hit it with a hammer and it almost cuts the stock in too, with out hardly a ding in the sharp edge.
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#5
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I think there's probably different physics involved between pounding a knife through steel like a wedge and chopping through it. Also it's highly unlikely that a swinging chop hit the nail at a perfect 90d angle, which means likely one side of the edge hits first and puts uneven stress on the steel while I'm sure when they hammered a blade through the mild steel that did their best to keep it close to a 90d angle. A last thing to concider is that the nails might be harder then regular mild steel, I'm not sure what kind of steel is usually used for nails, but it would make sense to be harder then annealed mild steel since it's intended to be hammered on without bending. You could try tempering a little softer if nails are likely to be chopped at alot, that way the edge will be more likely to roll then chip and will be easier to fix later.
__________________ ~Andrew W. "NT Cough'n Monkey" Petkus |
#6
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Quote:
__________________ Kevin Davey |
#7
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Retained Austenite in 1095
High carbon steels are notorious for retained austenite. That means after you quench it, not all of the austenite transforms to martensite. It leaves the edge softer than it should be for the carbon level. One way to deal with this is to cryogenically treat the blade. Since most of us do not have a tank of liquid nitrogen standing around, use dry ice. Quench the blade, temper at 250F, immerse in dry ice and alcohol, let it sit for about an hour, then allow it to warm up slowly. Temper at 450F as normal. And don't chop wood that has nails in it!
__________________ Which is worse; ignorance or apathy? Who knows? Who cares? |
#8
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thanks for the tips guys. you know how kids are he hacks and slashes everything in sight. sort of my field tester, if a blade can withstand him it will stand anything.
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blade, knife |
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