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  #1  
Old 11-17-2016, 01:32 PM
gkyle840 gkyle840 is offline
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multifaceted grind, Heat treat and and testing the blade.

So first I wanted to say that I got my grinder going, although not perfect. the belt wanders a tiny bit and its pretty unbalanced but it stays on and grinds. I used the grinder on my first knife today, the one that I plan to heat treat and break to learn about 1084. I put a multifaceted grind on it and it looks worse than any knife I have seen thus far. I am going to use 120 and 220 grit on it and then heat treat it and break it.
I have a few questions about breaking it to look at the structure of the metal. Do I heat treat it and temper it and then break it or do I skip the temper and just break it after the Heat treat? how do I go about breaking the blade? Am I supposed to bend it or smack it with a hammer?

here are some pics of my first grind

https://drive.google.com/open?id=0Bx...WFDMjBtcVQ0WTQ
https://drive.google.com/open?id=0Bx...mdObE9RcWlmU28
https://drive.google.com/open?id=0Bx...ll6bC1OaHlab3M
https://drive.google.com/open?id=0Bx...XR0cnllNFBxMDA
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  #2  
Old 11-17-2016, 03:31 PM
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Ray Rogers Ray Rogers is offline
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Yes, that grind is pretty crude. It appears that you probably didn't prepare the profile prior to grinding by first removing the corners from the edge portion of your blade. Not doing this means the sharp edges on the profile strip the grit off your nice ceramic belt and after that you are grinding with a dull belt. That's how a blade looks when you grind with a dull belt.

The purpose of testing the blade and breaking it is to see that your heat treat worked properly. Obviously then, the test is only accurate if you grind and HT the blade exactly the same way that you plan to make your blades. That means the same kind of grind and the same HT including tempering. Being as precise and accurate as possible is important because if you change much of anything when you do your real blades then the results may not match what you did for the test blades that allowed them to pass your tests.

When you break your blades, safety is paramount. Safety glasses at a minimum, full face shield if you have one (I use both together). You need a solidly mounted vise and about a 3 foot length of pipe large enough to fit over the tang of your blade. A couple of small pieces of very solid hardwood will be use to pad the jaws of the vise. The first i.5" or so of the blade is placed between the hardwood pieces which are in the vise jaws and clamped down. The pipe goes over the tang. You slowly bend the pipe over observing the angle that the blade achieves before it snaps. Some blades snap and throw very sharp shrapnel with considerable force so wearing a t-shirt and shorts might not be the best idea when you do this. Some blades don't break at all. Either way, we learn something.

Try to get a good picture of the grain and we'll go from there...


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Old 11-17-2016, 06:16 PM
gkyle840 gkyle840 is offline
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I just finished the hardening and put it in the oven for the temper. I tested it with a file after hardened and it skated off of the blade really nicely but it grabbed a good bit on the spine
we will see after I break it in 2 hours. I will post pics of the grain. I am also going to sharpen it first and test it a little.
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  #4  
Old 11-17-2016, 07:02 PM
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Yes, you should sharpen it first and test it. Especially do the brass rod test......


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  #5  
Old 11-17-2016, 09:12 PM
gkyle840 gkyle840 is offline
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I tested my blade on brass and chopping. it definitely has issues. the edge is pretty soft and folded over on the brass. when I went to break it I couldn't use a pipe as it was too short of a blade so I used a 5lb hammer. I hit it softly at first and it bent. I think it would have bent way past 90 degrees if I would have kept going. I struck a really hard blow and broke it and then took some pictures. the grains look wrong to me. can you tell if it got overheated or not hot enough by the grains? here are a couple pics, one with flash and one without.
https://drive.google.com/open?id=0Bx...W9pUVNucXhfMkk
https://drive.google.com/open?id=0Bx...0ppX0JoTWF2MU0
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Old 11-17-2016, 11:44 PM
jimmontg jimmontg is offline
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Are those cracks in the second pic kyle? You're right the grain is too big the way it looks. It should look more like grey velvet without all those cracks. Looks like you overheated the blade Kyle. The good news is that it isn't looking like it is too far overheated, but enough to make too much grain growth. How long and how high did you temper it? I looked at the magnification and that is some heavy grain growth, but I noticed you said the file skipped over it after HT. Hmmm...

Last edited by jimmontg; 11-18-2016 at 12:02 AM. Reason: addition
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Old 11-18-2016, 07:27 AM
gkyle840 gkyle840 is offline
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there are no cracks in it that are visible, in the second pic I believe we are just seeing a darker colored line. for the HT I got it to nonmagnetic and got a little excited and quenched it. I used canola oil and kept it submerged for about 20 seconds. I meant to keep it in the forge for about another 20 seconds but did not. after it cooled to room temp I tempered it at 400f for 2 hours. I have seen a lot of pictures of the grain structure of blades that have been overheated but I cannot find any pics of the grains of blades that have been broken after HT that were not heated to a high enough temp. could the grains still be large if the knife was not heated enough?
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Old 11-18-2016, 08:40 AM
WNC Goater WNC Goater is offline
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This may be helpful for your grinding. As far as grain, I can't help you, as I don't know what to look for anyway. "Fine" could be very subjective. But I agree with Jim, that looks like small cracks in the upper left. Could be a result of the hammer strikes... again I should shut up as I said.

Anyway, helpful grinding tips:
https://sites.google.com/site/vorpal.../grinding-tips


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  #9  
Old 11-18-2016, 09:19 AM
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Ray Rogers Ray Rogers is offline
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I've never hit one with a hammer so I'm unsure how that might affect the look of the break. One thing I am sure of though is that your blade wasn't too short to break by bending. Even a 2" blade can be broken by bending. Clamp the first third of the blade as described earlier, put the pipe on the handle and bend it. If the knife is too small and the pipe actually interferes with the bend then use a set of vise grips instead.

Technique aside, the grain looks coarse to me. Try again. Raise the temp checking often to catch non-mag on the way up (try not to go past that point). When you have non-mag, back in the forge for maybe 15 seconds (depends on how hot your forge is and how much mass your blade has). You want the quench temperature to be 100 - 150 degrees beyond non-mag.

Quench in warm oil, should be 90 - 120 F. Quench some mild steel bars to heat the oil if necessary. Once the blade is in the oil leave it there until it cools enough for you to comfortably handle it with your bare hands. Wipe off the excess oil and temper immediately. Temper for ONE hour at 400F, take the blade from the oven and let it cool in STILL air (don't wave it around) to room temp, and then temper it again for an additional hour. Now sharpen it and do your testing ...


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Old 11-18-2016, 09:37 AM
gkyle840 gkyle840 is offline
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I am going to cut a couple 1"x3" strips of the 1084 steel and HT this afternoon and test it some more. I heat my oil up to 150? and then start my HT with the blade. By the time the blade is out of the forge the oil is around 110-130?. I will lower the oil temp some. I am also going to change my quench tank to a vertical setup instead of the trough.
Are there any pictures or detailed explanation of the grain sizes at temperatures below nonmagnetic?
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Old 11-18-2016, 09:38 AM
dtec1 dtec1 is offline
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I agree that you should of bent the knife with a pipe not a hammer. I have made "coupons" to test the HT wich is just a square piece of steel and I have made them as small as 2 in x 1 in and broke it with a pipe so its deffinitly possible. also ray just pointed something out that I didn't see you or any one refer to before you have to heat up the canola oil. other oils don't make too much of a diference unless it gets to hot room temp is usually fine but canola it deffinitly makes a difference heat up scrap steel and when it gets hot stir it in the canola just don't heat it up to much...use a temp gun or a kitchen thermometer the one with a long rod on the end
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Old 11-18-2016, 09:40 AM
dtec1 dtec1 is offline
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just read your last post 150 is to hot for the oil try 100 or 110 I tried to keep it inbetween there when I used canola
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Old 11-18-2016, 12:13 PM
gkyle840 gkyle840 is offline
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I tried again. I heated oil to 110. I got steel to nonmagnetic and kept in forge for 30 seconds after. I did not temper but just broke the steel. it bent about 40 degrees before breaking. the grain looks finer but I still dont think its getting hot enough. the next piece I try I am going to intentionally overheat so I know what that looks like. I think my forge is just barely capable of getting hot enough until I figure out why my flame is not burning good once it is inside the forge.
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Old 11-18-2016, 12:27 PM
gkyle840 gkyle840 is offline
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here is the most recent piece. I still think it needs to be hotter but the grain size is definitely smaller than the earlier attempts.
https://drive.google.com/open?id=0Bx...W9zZkpjOGxXV2M
https://drive.google.com/open?id=0Bx...mQxYUxCMG55dDA
https://drive.google.com/open?id=0Bx...TBnSVV3eWtMRkE
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Old 11-18-2016, 12:39 PM
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QUOTE: until I figure out why my flame is not burning good once it is inside the forge.

Say what? Why is your flame anywhere besides inside the forge?

You say you got the steel to non-mag so that means your forge is getting the steel hot enough. Unless you are moving slower than Christmas 30 seconds should be more than enough time to re-heat the blade, possibly too much time but only more testing will nail that down.

This hasn't been discussed so far but how long does it take to get the blade from the forge to the oil? The oil should be a foot or two from the forge so that you can pull the blade from the forge and plunge into the oil without the need to take a single step. If you are walking even a couple of steps your blade has lost too much heat. From forge to submersion in the oil should take about two seconds, less if humanly possible ...


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1084, angle, belt, blade, blades, brass, edge, first knife, grind, grinder, grinding, hammer, heat, heat treat, knife, make, metal, post, rod, sharp, tang, temper, throw, tiny, vise


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