Edge geometry question

D

d.weglarz13

Joined
Jun 4, 2008
Messages
1,944
So, after studying many different styles of axes I am realizing that it seems mostly Swedish axes have a grind that stays pretty much parallel to the cutting edge, where as most western style seem to have the "banana grind," where the middle of the cutting edge has a wider grind at the bevel on the face as compared to the heel or toe of the head. Does that make sense?
So, what type of axe head would you guys say "need" a banana grind or even a Swedish style bevel? I ask mostly because I am starting to get into restoring older axes now, and would really love to know what about the geometry of the axe calls to grind one type of bevel or the other. And, since I'm starting to smooth out my council boys axe, I want to know what type of bevel would work best for it. It is pretty thin already, but both sides of it(faces) are so bumpy that after I took the paint off it years ago when I got it, I was really surprised how it covered up so well. I mean, the sides of the head are just so wavy, and I would like to smooth them out a bit since I love this little axe so much. And since ok doing all this I want to know the best way to profile the edge and bevels, plus I like to know since I have some more older ones that need some love.
I hope I am explaining this right, but I'm referring to the grind of the primary bevel on the face of different axes I think. I always see the banana grind, and often wonder why not put that bevel on other axes like let's say a gransfors for instance. So, thanks for any insights, I can't wait to start restoring some axes.

Dave
 
The banana grind is for axes that are thinner on the toe and heel. Swedish axes often have straight cheeks, so the entire edge needs thinned out. Since the toe and heel are thinner, that leaves the center of the bit thicker and that is why those are ground down more. If it has flat cheeks, like a gransfors grind it like a gransfors. If it has a tapered bit, then do a banana grind.
 
d.weglarz13 said:
....Swedish axes have a grind that stays pretty much parallel to the cutting edge, where as most western style seem to have the "banana grind," where the middle of the cutting edge has a wider grind at the bevel on the face as compared to the heel or toe of the head. Does that make sense?
Click to expand...

That 'Swedish' grind is called a radial grind. The grind is concentric with the bit.
Guitarist's explanation is good.

I'll add that either grind, banana or radial can be done with either a single flat bevel (Scandi grind) or a rolled bevel more commonly seen in N. America. For carving tasks a Scandi grind is desriable. But for chopping or splitting a rolled bevel is best. For chopping axes it's good to leave the rolled bevel at the toe a little thicker than on the rest of the axe. It won't cut quite as deep but it will be much more durable. Toes tend to wear out first.
 
Great thank you for explaining. Now that you mention toe, I have always wondered why my GB American felling axe since the day I got it, had the toe and heel sanded off. I mean they both look like someone hit them at a 45 degree to make sure they weren't sharp. I know that sounds a bit silly, but I figured it was a bad grinding job at the factory, but I loved the finish and everything else was near perfect that I thought I would just end up sharpening it out. I will try to get some pics of what I mean.
Thanks for clearing all that up though.

Dave
 
d.weglarz13 said:
Great thank you for explaining. Now that you mention toe, I have always wondered why my GB American felling axe since the day I got it, had the toe and heel sanded off. I mean they both look like someone hit them at a 45 degree to make sure they weren't sharp. I know that sounds a bit silly, but I figured it was a bad grinding job at the factory, but I loved the finish and everything else was near perfect that I thought I would just end up sharpening it out. I will try to get some pics of what I mean.
Thanks for clearing all that up though.

Dave
Click to expand...

Like this perhaps? I would like to know myself. Is this shape desirable or should it be groud off some. Is this what you were referring Dave. If not, sorry for thread hijack.



 
@Utican....No actually, the edge on my GB does not look quite like that. I don't have the knowledge to comment on that axe but it does look dangerous to me. I would be afraid to slip or deflect off my target. I mean, with an edge and belly like that, you almost have to hit perfectly square in the middle of the edge every time in order to not deflect off I would think. Someone who knows more will surely chime in.


I attached a few pics of my GB American Felling axe. It looks like someone knocked the very points off the toe and heel on purpose almost, and I have no idea why. When I first got it, I admit I knew even less and I thought there was reason for it. Unless there is? Now I think it was a shoddy sharpening job, or someone was drinking at the grinding wheel at the factory that day. I kept it because the rest, the fit and finish of the GB was just so superb, I really fell in love with it. So, now I'm afraid if I take the edge back a bit to get at those corners, I may end up with what Utican has there, except a newer and more expensive example.:eek:;) just kidding...
The rest of the edge is fine, and this thing feels great swinging and chopping with it so I'm sure it will get sharpened out eventually. But, it does kinda bother me that such an expensive axe came from the factory this way. And no, they didn't break off or anything, its been this way since day one. So, what do you guys think about this? Am I wrong and is there a reason for this? Thanks for any help or ideas..Do I just wait or should I sharpen those areas good and sharp?

thanks for looking....
sorry for the crappy pics
Dave

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I have trail crew and some man-powered logging experience... The plumb isn't dangerous, just as long as it has a good sharp edge,it shouldn't deflect. As for the GB, they probably round the corners to prevent chipping. A thin, sharp toe, especially can be prone to chipping and breakage. I don't know how many vintage axes I've restored whose heel and toe have been rounded over time, because they chipped and then were ground down.
 
Interesting. Thanks. So then it seems they did in fact do this on purpose.
Do you think I would be ok if I were to sharpen the heel and toe out a bit? I would prefer to but I would hate to break a corner off. I won't go to thin....
 
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