say if i was to have a knife that was double beveled and knew a guy who could sharpen it to a single would that ruin the blade
P.S i just wanted to make it sharper because usually singles are more than doubles thanks
If you have a "good" knife and it has a double grind (eg. either a flat grind with an edge grind or a hollow grind with an edge grind) I would not have it ground to a zero bevel grind. A knife should really be planned to have a zero bevel grind, not altered later to have one. Zero bevel ground knives are not actually "sharper" than a double ground knife. The only way to make it sharper per se is specifically to decrease the angle of the edge grind (whether this is done through a zero degree grind or a double grind with a shallow edge grind angle is irrelevant). It is always a compromise when grinding an edge to a more shallow angle. The compromise is between edge strength and the sharpness of the edge. Scalpels are normally ground with a 10 degree edge, however, that edge will not hold up to a hard material such as wood. A 30 degree edge grind will hold up to wood, however it will not be as sharp as a scalpel edge ground to 10 degrees. One other thing to take into account is that you can actually shave with an edge ground at 30 degrees if that edge is finely honed or stropped.
the seconds grind, or what I have always seen called a blade bevel, is very important to a good knife. the only kind of knife edge that should not have it is a straight rasor. it may be slightly less 'sharp' but it will be much stronger... better is just about every situation you would want to use a knife
30 degree grind is far too thick to use whittling wood. 30-35 degree is used for choppers. Right angle for whittling wood is 22 degrees. Here in Scandinavia we don´t really now double bevel knives, our knives are single beveled and very sharp. They might have tiny micro bevel as secondary bevel to make the edge stronger.
Most of the double bevel knives are designed to be like that and are very difficult to convert as scandi grind. But what you can do to improve it´s cutting ability is simpe convexing it.