Yes, it can be nerve wracking when you first grind the edge.
Some people scribe two lines in order to leave the desired thickness (say .020) prior to heat treat. This has the added benefit that if you go a little too far you don’t go past center and therefore you don’t affect the final edge.
I grind after heat treat, so I only scribe a single centerline. My first grinding step is to grind a 45 degree angle (give or take, in reality it’s just knocking the sharp corner off. The angle is irrelevant.) I grind to the scribed line as closely as I can but still maintaining the scribed line. The reason I do this is because that layout blue and the line are going to fade away sooner or later in the grinding process. Having a straight cutting edge defined already while I’m grinding takes out the guesswork when the visual reference is gone.
Once I establish this edge then I begin on the bevels. I establish a “flat” out there away from the cutting edge. From there on, it’s all about playing the game of trying to get my bevels to reach the spine (or wherever the top is going to be) and the edge at about the same time.
Freehand grinding clears my head. Since I have no way of knowing what angle I’m grinding at, I no longer obsess about angles. I don’t care because I couldn’t control it even if I did care. The final angle is baked into the the design. All I have to do is get the bevels to meet at the cutting edge.
The thinner the blade gets as your bevels grind in, the easier it is to see the final edge. It’s a lot harder to grind too far than people think. It’s a lot trickier to stop the bevel in the right place at the top, if you plan on having flats at the top.
One piece of advice, and this is just my opinion and my way of thinking- but where freehand grinding mistakes happen is usually when you present the blade to the belt and make contact. In a perfect world you’d lay the bevel on the belt perfectly flat. That doesn’t always happen. So my advice is to approach slightly edge in. If the blade doesn’t land perfectly flat I’d much rather the edge hit first than the spine. If you knock a tiny little bit off the side of the edge it usually won’t matter because that’s the steel you’re trying to grind off anyway. But landing on the top of the bevel may cut a trench that was intended to be a pretty flat area on the final blade. Now you have to grind that whole side to get past the trench and then do the same on the other side.
After all, think about just how much steel you’d have to remove at the edge to hurt a knife. You could remove 1/16 along the whole edge and nobody would even notice.
Of all things to fix on a knife the edge is about the easiest part to regrind if you had to fix it or re-center the cutting edge, at least on most knives.
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