Grinding bevels

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sjensen85

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Jul 18, 2013
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So I have made my first knife:

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I messed up a couple things. Not sure why I put the later choil(?) directly under the edge. I wanted to make the blade mainly for chopping, but also useful for other tasks (not filleting fish or anything of the sort.) I ground the entire bevel at one angle, what I was guessing was around 20 degrees, but don't really know. On first test, the edge folded over. It was mainly at the bottom inch - inch and a half. I figured this was decarburization, so I kept going at the same angle until I removed the entire folded over portion of the blade, and evened the rest of the blade out a bit. I started thinking while grinding, that maybe the edge was just too thin. So I went to a steeper angle on the edge. This worked out alright. A couple more tests and it seemed to work well, no more folding (at least until we started throwing it and it hit other metal, then a little more folding happened - not nearly as bad though. Why did we start throwing it? Well, it is actually a really well balanced knife and I didn't care too much as this one was a learner.)

I have read a few threads that have stated thicker for chopping, thinner for slicing. My questions are, do you grind to the edge or do you put a second bevel on the edge for certain types of knives? What angles do you generally use for each type of knife (the stock I have at the moment is 1/8" thick?) My bevel is not as pronounced as others, should I have gone at less of an angle to make the bevel wider (when I was filing I felt this was almost too little of an angle, but the edge came to shape pretty quickly?)

Thanks a lot for reading this, and hopefully it is not too repetitive. I just couldn't find the right threads to answer my questions.
 
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What type of steel, and how are you heat treating it? BTW, the mods will ask you to fill out your profile. It allows us to help you better.
 
^^+1 It looks like my first blade I tried to grind on a 36 grit ceramic. Is your goal here to get a usable knife that looks finished, or just a blade you can test?
 
Always give the steel type, source, and HT info with a blade post. That helps folks give accurate advice.

After making the main bevels you harden the blade. At this point the edge is a flat surface about half a dimes thickness or so ( .030" is good). After the final sanding and finishing, you place a small secondary bevel at the edge during sharpening.. If you don't, the angle of the blade will be very low, and it will roll or chip. The secondary bevel for a chopper is normally about 15° per side (30° inclusive) a slicer is about 10° per side.

The fact that the edge rolls is an indication that the blade did not fully harden in HT, or the blade was over-tempered. When ground thin, a hard edge will chip, a soft edge will roll, a just-right edge will flex.

I am not sure why most folks try and make a first knife capable of fighting Grizzly Bears, but making a smaller drop point hunter would be a better choice for your second knife. On that one, spend a lot more time sanding the blade with a hardwood block and sandpaper before and after HT.

From what I can see in the photo, your handle looks pretty good. One place you might have problems is with that little projection of wood sticking out at the ricasso (between your thumb and finger in the photo). That will easily snap off if struck in use, especially in chopping. You should make the handle front round back to the finger choil, and not stick out as a point.

Your little edge choil should be placed bisecting the plunge. Half should be on the ricasso and half on the edge.

These are just things for knife number two. Your first knife is pretty good as first knives go.


Now, as Willie pointed out, fill out your profile with all the info, like age, location, occupation ( or student), and hobbies.
 
chavez556 said:
^^+1 It looks like my first blade I tried to grind on a 36 grit ceramic. Is your goal here to get a usable knife that looks finished, or just a blade you can test?
Click to expand...

At first, it was to get a knife that was finished. Still have a lot of work to do on this blade - I was just doing some initial testing after the HT and temper.
 
Steel is the normal 1084 (at least I believe it is the normal 1084, did not have an fg on the stock) from usaknifemakers.

The fact that the edge rolls is an indication that the blade did not fully harden in HT, or the blade was over-tempered. When ground thin, a hard edge will chip, a soft edge will roll, a just-right edge will flex.
Click to expand...

This was my first thought as well. Is there a way of telling which did not go as planned? Can I still HT now that the [almost] final edge is on the blade? I am thinking if it isn't because of the tempering, that I need to improve the quenching (actually need to do this anyway.) The quenching was done in a glass baking dish. I am not sure of the temp of the oil. The oven was on the lowest setting, which I think was 175, but the oil did not feel this warm. For the HT I took the blade out, pretty much, as soon as it lost magnetic properties. The HT was done in a fire. The tempering was done at 400 deg for 2 - 2 hour cycles, cooled completely between cycles. I am thinking I definitely need to get a couple thermometers as the oil did not seem to be 175. As far as I have read, quenching oil should not be more than 120 degrees anyway, correct? I used typical canola oil for this.

I am not sure why most folks try and make a first knife capable of fighting Grizzly Bears, but making a smaller drop point hunter would be a better choice for your second knife. On that one, spend a lot more time sanding the blade with a hardwood block and sandpaper before and after HT.
Click to expand...

I know, I originally did not have a big knife like this planned. I decided on this later, for unknown reasons. My next knives are going to be smaller.

From what I can see in the photo, your handle looks pretty good. One place you might have problems is with that little projection of wood sticking out at the ricasso (between your thumb and finger in the photo). That will easily snap off if struck in use, especially in chopping. You should make the handle front round back to the finger choil, and not stick out as a point.

Your little edge choil should be placed bisecting the plunge. Half should be on the ricasso and half on the edge.
Click to expand...

I actually have to redo the scales in general, and realized that I didn't like that part of the handle anyway. I have completely filed the small choil off entirely at this point, so I was going to place it pretty much were you are indicating.


Thanks!
 
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bladsmth said:
I am not sure why most folks try and make a first knife capable of fighting Grizzly Bears, but making a smaller drop point hunter would be a better choice for your second knife. On that one, spend a lot more time sanding the blade with a hardwood block and sandpaper before and after HT.
Click to expand...

I have given some 8" lengths of 1084 and black walnut to a few people who have expressed an interest in knives, and they have all come back with "how do I make a 12" dagger from this?" or "how do you attach the handle to the 8"blade?" I even draw a nice drop point hunter on the steel as a suggestion. The only one who finished a blade made a kiridashi with a micarta handle. Its a lot more work than it looks.
 
I would be willing to place a large wager that your HT was faulty.

It takes at least a gallon or more of oil to quench a blade that size. The best quench method is straight in, point first. A tall can or bucket will work for the tank.
The oil should be at about 120F. Canola oil will work for 1084, but stay away from other "home quenchant" oils, like motor oil and ATF. Eventually, you will want to get some commercial quenching oil, like Parks/Heatbath #50, for 1084 and 1095.
The best way to warm the oil is to heat up a piece of steel and stick it in the oil, stirring well. Check the temperature with a cooking thermometer and repeat as needed until it is about 120F-130F. Then, start heating the blade steel. The oil will stay hot enough for the quench.

Your heating method is about the worst one there is, but it is all you have right now. You heat the steel as evenly as possible, trying not to overheat the edge( hard to avoid in a fire pit), and when it is non-magnetic, you want to heat about 100F hotter ( just a shade of red higher). This is also nearly impossible to determine in a fire pit. When the steel is at the target temperature ( about 1450-1500F) quench in the warm oil.
As soon as you can, you will want to build some sort of forge.
 
Thanks for all the useful info Stacy. It is greatly appreciated.

I have seen very basic forges with a basic pit with charcoal used for cooking. But what I have read/seen on blacksmithing, this charcoal is not ideal. Would it be more ideal than the fire pit though? What type of forge would you recommend that won't break the bank?
 
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