With this freehand sharpening method using three flat diamond sharpening stones, you can achieve a razor-sharp edge on your chisels without needing fancy jigs or honing guides.
Pour some honing oil onto the coarse stone’s diamond plates, then grip the chisel with one hand on the handle and the other near the blade — at about a 25- to 30-degree angle.
Pushing the chisel away from you, use long, steady strokes to remove any large nicks. Next, use your medium grit stone to refine the edge and smooth out any rough scratches.
Finally, use the super fine grit stone with light, consistent strokes to create a precise edge. Finish with a leather strop and polishing compound to achieve a mirror-like shine.
Hold the chisel with the bevel facing down, and draw it back along the strop 30 times at the same angle as used on the stones. Then, strop the back flat against the leather.