Axe and Draw Knife bevel angles

[Claus]

I have a few old drawknives and a single bevel axe that I struggle to sharpen. Actually I can get an edge but it doesn’t last because the bevel angle looks too steep, on one tool I estimate it at around 40 degrees. These are old tools and I think that they’ve been sharpened so much that the cutting edge has gotten more and more narrow, hence the steep angle.

Normally with a hand plane or a chisel I would go to a grinding wheel to fix the primary bevel (sharpening 101 textbook scenario). But the wheel leaves a hollow grind, essentially a slightly concave bevel, ok for planes but not really for an axe or drawknife as the edge would be too fragile with a hollow grind. Blacksmith quality new tools like this have a flat grind rather than hollow and they work really well for me.

So, what’s the best method to put a flat a or even slightly concave bevel on these tools? I need to remove quite a bit of material and stones, even coarse, aren’t working. Any input/comments would be appreciated.

BTW - these are for working with wood riven from green hardwood logs, much like the work done by Peter Follensbee.

 

[Mike Davis]

I use a grinding wheel sometimes and I have learned to move the tool on successive passes so the edge does not form a groove or as you said a concave profile. The draw knife can be flat or convex grind but the ax should definitely be convex. A loose rule of thumb is for the bevel to be about 2 - 2 1/2 times the thickness of the tool. On the ax that thickness would be measured about 3/4 to 1 inch from the edge.

If you find the grinder difficult to use for a convex grind then the slack part of a belt sander works really well. I use a 1 x 30 inch belt sander.

 

[mkepke]

I'm far from an expert, but my go-to solution for an axe that needs significant work is a bastard file.

For re-profiling drawknives, it's a belt sander and a jig. I used a 6x48 until I bought Mike's 2x72 belt grinder.

-Mark