Sharpening a Knife with a Belly (Inside Curve)

CDHumiston

CDHumiston

KNIFE MAKER
I am working on a couple of knives that have what I would call a belly. I borrowed a picture from another thread here to show what I mean.

How do you sharpen the portion inside the black circle? I'm using my grinder to sharpen/form the edge on the blade. Due to the shape, you can't just run the edge across a flat platen. Seems like I have to draw it on the edge of the belt.

IMG_4751.jpeg
 
I had a Bowie I made a couple years back that has a slight recurve. If I recall correctly I put the belt about a 1/4" over the edge of my flat platen and worked on it that way Then I finished up with stones. It's been awhile. But I'm fairly certain that's how I did it. I don't have a finished photo, but here is a WIP. As you can see your recurve is more pronounced. I hope this helps

https://imgur.com/yXmdPmh
 
You have to use a belt narrower than the full 2", like 3/4' - 1", depending on the curvature. I've also used lansky (sharpening system) stones, too which are less than that and leave a nice clean finished bevel.
 
You have to use a belt narrower than the full 2", like 3/4' - 1", depending on the curvature. I've also used lansky (sharpening system) stones, too which are less than that and leave a nice clean finished bevel.
 
I've never done a recurve blade, but I'd think a slack belt might one way to help you get where you want to be. Or, use the 2" wheel at the top of your flat platen arm. Even better if your 2" wheel is rubber. If not a lighter touch may do it, but the belt bump might be too much..
 
soundmind said:
You have to use a belt narrower than the full 2", like 3/4' - 1", depending on the curvature. I've also used lansky (sharpening system) stones, too which are less than that and leave a nice clean finished bevel.
Click to expand...

I have a 1" x 42" belt grinder. I may give that a whirl!
 
Sounds good - I also admit to not having done many. I remember figuring it out though when I was using the slack belt between the tracking and idler wheels. I noticed the sides of the belt would bend away with pressure and I'd have less contact at one time on the recurve edge.
 
I've only sharpened a couple of re-curve blades. I found that if I used the horizontal portion of the 2" belt that was above the upper platten - AND, loosened the belt tension - I could get an adequate edge grind. But, if not careful, the edge of the belt can dig in. So use either a J-Flex belt or a scalloped-edged belt. I found a 2" scalloped belt somewhere, either Pop's or Tru-Grit.
BTW - nifty looking blade!
 
You have to use a narrow belt, and/or favor just the corner of your platen with the belt tracked over. Just be careful not to slice your belt. If you can reverse the belt, all the better.
 
I've used the slack belt above the platen and a Lansky system. For that big recurve, I'll probably try a 1" scalloped j-flex I have and see if that works better.
 
I sharpen on my 12" wheel but on the inside curve I just use the edge of my wheel
043e3f1d15b72eb155a8366eea23162e.jpg


Sent from my SM-G981V using Tapatalk
 
I always sharpen on the slack belt between the idler wheel and the top wheel on the platen. The grinder is run in reverse. I’ve done a few recurves that way with no problems.
 
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