Drop choil?

[Lin Rhea]

I have had some newer knife makers ask how they can get the choil to drop down straighter on the back of the cutting edge. First off, for some who don't know axactly what the choil is, it is the "heel" that is sometimes dropped down below the bottom of the Ricasso.

Lets look at it this way: We all have our strong point in knife making. Some can forge well but may not grind well and vise versa. Lets assume that most are just OK at forging, but will make up for weak forging at the grinder. OK?

My goal is to convince you that you can improve your grinding by making a small change to your forging AND then changing the sequence of your grinding.

I have some pictures ready to illustrate the steps.

Forge the blade as close as you can. But when you forge in the plunges, lean them forward at an angle.
 

In the above photo you will see that the blade has been mostly profiled just after forging. I knocked the high spots off and got it looking kind of like a blade. However, I did not touch the choil on the grinder. I'm saving that material for later. The next pic shows the ricasso sides being flattened a little and getting rid of scale. But it makes it easy to see the sloped plunge.
 

In the above picture, notice that the choil has some material that is now available to be removed, affectively straightening up the choil. Lets go to another picture.

 

In the above picture, the plunges have been started but notice that they are forward of the choil by a good margin. I now work on the other side and will change the grits if I can, while settling the plunges in evenly but remaining forward of the choil. This un ground area of the choil gives you some room to bump the choil forward again if need be.

The next picture is to show you the unfinished choil. There is still material that has to be removed so why not just allow for it in the grinding process?
 

In the next picture I have bumped the back of the choil closer to a vertical position, being sure to allow for the subsequent grit changes and finishing.
 

You can see where I'm heading now. The sequence is very important or you will be chasing your tail and end up with the choil way in front of the plunge.

All knives don't have dropped choils, nor should they. But I know that some are trying to get them just right and are struggling. I hope this will help. I can try to make it clearer if you need me to. Just ask.

[gables]

Great post, thanks for taking the time to illustrate. I have always liked how you maintain a slight choil edge on the back side of the plunge. That's hard to explain but something I have noticed on your knives. It appears that you slowly bring in the choil to your plunge but leave a little ridge of material that you may even later shape. Am i understanding correctly?

   

[DANA HOLMAN]

Good thread Lin, this should help alot of people.

[Lin Rhea]

Yes Jeremy, but more important than anything is to get control over the result. Not so much hit and miss. Each step of the grinding has its place on a list of priorities. To my way of seeing things, the plunge, since it is much more difficult to get right and even, comes first. So, I actually get it the way I want it first, then bring the easier choil forward to meet it.

But again, the material has to have been forged into place in order to grind it to it's final shape.

On the above examples, I have ground to 60 grit and will start back on the ricasso, then blade flats, then just lightly touch the choil. Actually, I could stay off the choil completely until the finer grits. This way, you can dial it in to look like you want it.

[DANA HOLMAN]

Lin, Is there a rule of thumb about the choil, as far as the curve/slant, most of my choils are slanted a little more then yours. I also remember a talk we had about how to forge the choil down. Thanks for that help.
Dana

[Lin Rhea]

That's a good question Dana. The only "rule" is that things need to be even/symmetrical. The rest is subject to opinion and taste.

But you and I both know that while being ugly might not be breaking a rule, we much prefer pretty. So, let's just say that another rule is that it needs to be pretty.

We're still talking about knives, right?     One can make the other look good or it can clash.

So, while your question is good, I cant pick which woma......shape of choil looks good to you. Then you have to figure in your individual taste and tooling (platen radius etc.)to make it happen.

[Lamey]

when I had flat dies in my power hammer I would just use a 1" thick "paddle" to set the choil.... this made it really easy to pull straight down and stay off the ricasso.  

since I no longer have those flat dies in the hammer, I do a lot more by hand hammer and the edge of the anvil etc...

good stuff.

[kbaknife]

I cheat. I go in reverse.
I forge the whole knife out wide, then forge the choil DOWN, leaving the cutting edge in place.
I just made a little slotted jig for my press and do it all in one squish.