The bevel or grind of a blade refers to the shape of the cross section of the blade.
Along with the steel type, heat treatment and the thickness of the blade, the grind shape and angle determine cutting performance and blade strength.
In general the steeper the grind and the less material behind the edge, the sharper the blade.
On the contrary the less steep the grind and the more material behind the edge, the stronger the blade.
Furthermore a less steep angle can also be combined with less material behind the edge.
This gives a durable edge, while it reduces friction when cutting.
Examples are a convex grind, double grind and hollow- or flat grind with a less steep secondary grind.
Depending on the application of a knife sharpness is less or more important than strength.
I will make 20° angle sabre grind (giving a total- or "included" angle of 40°).
I think this grind provides a good balance between blade strength and cutting performance for a bushcraft knife.
To reduce friction you may want to convert the sabre grind into a convex grind.
Marking out the grind boundaries
Some knife makers use a jig that keeps the file on the same angle while filing in the grind.
Though you can easily file in the grind without the use of a jig.
To get a grind with the desired angle, you'll need to mark out the grind boundaries.
Measure the thickness of the blade with a caliper.
If you used a file that tapers in thickness, measure the minimum and maximum thickness of the blade.
Calculate the grind width b:
b = T / (2tanα)
with blade thickness T and grind angle α.
Mark out the calculated grind width on the two sides of the blade using a scriber and caliper.
Color the edge of the blade with a permanent marker, so that a scribed line will stand out.
Place the blade on a flat surface.
Scribe the edge using a drill bit with diameter T (thickness of the blade).
This way you get a line running along the center of the edge.
If you used a file that tapers in thickness, put something underneath the tip of the blade to compensate for the taper.
Filing in the grind
Secure the workpiece into a vice.
I you want to have a small ricasso (unsharpened section of the blade near the handle), clamp a piece of steel to the blade as a means of guiding the file.
File in the grind on both sides of the blade.
Apply the same filing techniques you've used to refine the knife profile (step 5).
Regularly check if the edge is straight.