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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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test knife
finished my first knife and got it sharpened up. whittled through a 2x2 board, then went straight to shaving paper, then cardboard, then paper again (cut up a large paper towel box). Unfortunately I didn't have a brass rod to do that particular test. I used 5/32" O-1 steel.
Clamped it in a vise about 1/3" from the tip and pulled, blade snapped at about 30 degrees from what I could see on my video. I took the best pics I could, can't wait to hear your feedback. Last edited by RedstickJP; 04-15-2015 at 01:53 PM. |
#2
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Sounds like it performed OK and the grain looks good as far as I can see it. But 30 degrees is a little sooner than I would choose to have it break, I see two possibilities for ways that might be improved.
One could be the vise you used: did you put a piece of hardwood on each side of the blade so that the blade couldn't touch the steel jaws? If not, the sharp edge of the jaws will cause the blade to break early. Or, if it isn't the vise jaws then the steel might be a little too hard so a slightly higher temper might be in order. This assumes the grain is as fine as that picture makes it seem but its a low res pic so can't be sure. If it broke because of the grain then better temp control before quench is usually the culprit ... |
#3
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The grain seems to be pretty fine, but since it's my first one I don't really know what it should look like if it's too course. I did use two pieces of 3/4 plywood, had to clamp pretty tight. I tempered at 400degrees for 1hr, let it cool back to room temp then did another hour. I'll try to get a better pic of the grain.
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#4
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The break in the blade is kind of far from the tip. That leaves a short, stiff, section of blade that you were bending so that too can make it snap early. Clamping about an inch of the tip or a bit more is usually good on a 4 or 5" blade .....
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#5
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ok. When I was doing the tempering I noticed that my blade never changed colors, should it have changed to the straw color that I keep reading that other people are getting? Its an old oven, but I know it was at 400 because I used a digital thermometer. I didnt do anything after the quench except scrub the oil off, should I have sanded the blade first?
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#6
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Two things that I noticed from the pics..... 1. The blade doesn't seem to have much distal taper. (Tapering from the ricasso to the tip). Distal taper do two things for a blade..the lighten the over feel considerably, and they increase the way stress is dispersed when a blade is bent. 2. Square edges at the spine..... rounding off the spine reduces possible stress risers (places where a break starts).
Finally, flexibility is not O1's strongest suit. O1 hardens well, but compared to other carbon/alloy steels such as the 10xx series, and 5160, its just not the best choice for a blade that encounters lateral flexing. If the blade was "clean" prior to tempering (ground clean), it should have certainly shown some color..... generally at 400F, I'd expect to see straw color, with a little vermillion mixed in (reddish purple). From what I saw in the pics, the grain size is about average for O1..... in my experience the best way I can explain what I like to see when it comes to "grain"....is that is looks like melted, swirled up vanilla ice cream. Personally, I don't think a 1 hour temper is enough. I've seen too many instances where folks have come to me for their ABS JS test(s), and had a blade break during the bend test....without fail its always had to do with either the tempering method, or the length of time the blade(s) where tempered. I've also done my own experiments, and found that in many cases a shorter tempering time only creates a "tempered skin" around the whole exterior of a blade.....generally a 1 hour tempering time on most steels I've tested only gives about a .010-.020 depth of temper (in other words the tempering does not go all the way through the cross section of the blade(s) ) __________________ WWW.CAFFREYKNIVES.NET Caffreyknives@gmail.com "Every CHOICE has a CONSEQUENCE, and all your CONSEQUENCES are a result of your CHOICES." |
#7
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How long would you recommend? And no the knife didn't have much taper, hoping to improve on that the next time around. Glad two of you said the grain looks good, I was worried since it was my first HT and since I know an electric furnace is better for o-1 since you can keep the temp even. I do have some 1084 otw for future projects :-)
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#8
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I always temper in two hour cycles. Definitely with something as complex and high carbon as O-1. It would be better for 1084 too.
Doug __________________ If you're not making mistakes then you're not trying hard enough |
Tags |
1084, 5160, abs, back, blade, brass, carbon, choose, degrees, digital, edge, knife, make, o-1, rod, sharp, show, steel, temper, video, vise |
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