sharpening help needed.

Guindesigns

Well-Known Member
IMG_30032021_201736_(880_x_880_pixel).jpgI have gotten into a bad habit of giving ever knife I've sharpened here lately an unwantwd recurve.
What are some remedy for this?
Right now I use a 1 inch jfelx belt on my grizzly, I know I know way to fast but it's what I learned on and this has only started happening as of late, any help will be welcomed.
I also have a KMG with the pulley system as my main grinder set up if that helps or gives any ideas.
 
That’s the pitfall of slack belt sharpening when the belt has a dome to it. I started using the contact wheel the same way you would use a Tormek type wheel. Then I slack belt the burr off. The contact wheel is also wide enough that it makes the belt lie flat right before it enters the wheel. I can slack belt there about an inch or two before the wheel and the slack belt is stiff and flat.

On a Grizzly the speed is an issue, but very light pressure and moderately fast strokes ought to work.
 
In addition to what John said..... that is clear evidence that you are applying far too much pressure when slack belt sharpening. Even with a nicked up edge, no more pressure than the weight of the knife.... even if it does take several passes. Slow down, and ease up. I have shop knives that are decades old, and have been sharpened via the slack belt, on a weekly basis....and the edges are still straight..... just gotta be easier. ;)
 
Ed, that’s a great point about pressure. I was very guilty of that for a long time and was getting the same recurve as Guin. It happens very quickly, too! I was using the blade to flatten the belt out, thinking that of the belt was flat that it would cut flat. Just that tiny bit of extra pressure that the belt is exerting where the blade is pressing down the dome of the belt is enough to really eat the steel. The other pitfall is trying to get the edge sharp all the way to the plunge on a domed belt. I would put the plunge on the edge of the belt and rock the knife to follow the curve of the dome. Seemed like a good idea in theory, but having such a small area of the blade in contact with the belt at any one time only made the belt cut out the blade even more.

In my experience I have found that it’s all about having the belt as flat as possible. Not only does that keep your edge straight, but you also avoid that dreaded mistake of the dome of the belt scraping all the way up the blade to the spine and having to hand sand the blade all over again.

There’s a good reason so many makers prefer to use stones. It is very easy to botch up a blade sharpening it on a belt.
 
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