Re-shaping a double-bit axe head

R

RickW

Joined
Nov 5, 2005
Messages
167
I recently got something I'd been wanting for a while: a good double -bit axe. Its a Grandfors Bruks, but it isn't in very good shape. It's been incorrectly sharpened, and I want to re-shape it. Here is a picture:
My question is: How do I determine the right shape for the edges? Also, one side of the axe is longer than the other, by about 3/8". To make the edges the same distance from the center, I'd have to remove that much from the longer side. That seems like a lot. I want to re-shape it and hang it on an octagonal handle I have.
If this info is somewhere in this forum, please direct me to it. I will be grateful for any advice.
Thanks,
Rick
 
Unless you can find the exact model and pictures of it (this looks to me as a vintage one), you cannot tell the exact shape...so I'd only venture to say as much as "rounded" :).

Anyway, I wouldn't obsess over this, every sharpening may alter the "perfect shape"...in an effort to minimize good steel thrown away. This brings me to the other point: yes, you definitely want to preserve as much of the hardened steel as possible. Based on the hardening lines, which are not straight (hence I'd say they are in fact weld lines...), these may be inserted or overcoated bits; if the latter, the actual good steel may extend less than what the side view would suggest. (You may be able to tell apart overcoat vs inserted by looking from the top of the axe.) It does not matter, in the grand scheme of things, that one side has been sharpened more than the other one - you won't be able to tell from the balance...which for any double-bit will be by default better than for a single-bit. Just use the "healthier" side more.

I am assuming you will use this axe, and it won't be a wall-hanger. For the latter, the symmetry may have some value...
 
best way is an angle grinder with a rough flap disk, but dont wear gloves so you can easily feel the heat of the metal
 
Thanks for the responses. I'm glad to know that the difference in length doesn't really matter. I'll just hang it, sharpen it, and use it.
BTW, the dark areas on the axe head are where I painted it with Dykem, in order to see my layout lines where I found the center of the eye and measured the length of the blades.
Rick
 
FYI it's traditional for double bit axes to have one longer bit and one a little bit shorter, so don't worry about that because it's how it's supposed to be.
 
RickW, I find more double bits around here than many other patterns and I have to ask myself this same question.

Sometimes it’s helpful to find a picture or example of what heads look like when they are new to make a comparison. I wasn’t sure what your axe head looked like when it was new but here is a Google search image for “vintage Gransfors Bruk double bit” that looked somewhat similar to yours:

GBdoublebit.jpg



The edges normally look pretty straight from the heels to the toes on both bits unless they are originally designed to be more rounded when they are new.


A lot of times the toe (upper part of the bit) is worn more than the heel (lower part) – the toes get the brunt of hitting rocks, dirt, and often more wear just from more contact with wood. With that in mind, here is your head flipped over:


gransforsdouble.jpg


I don’t know if yours should be oriented that way without seeing the eye or you maybe taking measurements.


If you want it to look more “original” then you really might have to remove more material that you should to make the toes and heels even.

Example:

gransforsdoubletoetoheel.jpg



Sometimes it’s helpful to use a sharpie to draw out where toe to heel is on the edge and then sketch out where you want the actual edge to be. Some guys use a grinder to take off the excess material then create a profile back to the line, I usually use electrical tape as my marker and readjust as I go.


There are some really good tips, tricks, and videos about how to go about grinding, filing, and reprofiling old axes around here that can be dug up. Square_peg has a video on filing an axe if you choose to do it by hand:

Thread:

http://www.bladeforums.com/threads/filing-an-axe.1418233/



Keep in mind that I could be totally wrong about the "new" example of your axe that I Googled up, the orientation of the head, and what you want it to look like but I was thinking about it as if I wanted to rehab it for my own use. With the wear on it, I would probably not try to make it as straight as “original” or “new”. Sharp? Yes.

*I reserve the right to change my mind based on new information ;)
 
There might be/have been double bits designed shorter or stubbier to one bit but I am under the impression that most were/are intended to be even "at birth" and they got shorter on one end from use.

I'm ok with being wrong as well.
 
Agent_H said:
There might be/have been double bits designed shorter or stubbier to one bit but I am under the impression that most were/are intended to be even "at birth" and they got shorter on one end from use.

I'm ok with being wrong as well.
Click to expand...

That is my impression as well. I know there was a pattern with different bit lenghts, I think manly because of one of the bits being straighter than the other one.
 
Thanks for the additional replies. They help a lot!
My picture shows the axe head in what I think is its proper orientation. That is, the wider part of the eye is at the top. It would look better if the part of the axe that is more curved was at the bottom, but that's not how it should be hung. Or is it?
Thanks for the picture of the vintage Grandsfors Bruks axe head. I looked at the pictures of the new ones, which are very curved top and bottom and very symmetrical. The picture you posted looks much more like mine.
I think I will try sharpening it with a little less curve in the edge. I probably won't use it that much, so I can also try other sharpenings too.
Thanks again for all the responses.
Rick
 
Bigger side goes up. It may have been abused, by hitting the top with a hammer to "secure a hang", but you should tell from the marks - no one doing such awful things :) would take care to use a piece of leather or such to prevent the marks on the side of the head.

Due to repeated sharpenings, sometimes the toe may be "consumed" more than the heel.
 
It is my understanding the the shorter blade is also wider and is designed for more rough use such as cutting roots or where there is a possibility of striking stone or dirt. The longer blade is also thinner to hold a sharper edge. The difference in thickness balances the difference in length as far as weight of each side is concerned.
 
Agent_H said:
There might be/have been double bits designed shorter or stubbier to one bit but I am under the impression that most were/are intended to be even "at birth" and they got shorter on one end from use.
Click to expand...

That's correct. They leave the factory essentially equal, less whatever difference happens by incidence during the grind. The 'rough service' end gets dulled more often and worn out faster from repeated filings.

RickW said:
My picture shows the axe head in what I think is its proper orientation. That is, the wider part of the eye is at the top. It would look better if the part of the axe that is more curved was at the bottom, but that's not how it should be hung. Or is it?
Click to expand...

Yes, typically the wider end of the eye goes up. This makes for the more secure hang. There were 'reversible' pattern axes made with hourglass shaped eyes that were equal on each end. These were designed to be flipped at each re-hanging to compensate for the greater wear on the toe.

One of the chores of the man who was a swamper in the lumber camp was to limb the fallen trees. This often involved work closed to the ground. Their axes were frequently damaged and abused. Also, a swamper pattern axe was sometimes made thinner specifically for the task of limbing where a fine sharp axe is handy and there's no real need to pop the chip.

A feller might likewise use one side of his axe to bark the tree, work that might expose the edge to abrasive dust. This edge would have a little wider bevel. The other side would be filed finer for efficient chopping.
 
Square_peg said:
That's correct. They leave the factory essentially equal, less whatever difference happens by incidence during the grind. The 'rough service' end gets dulled more often and worn out faster from repeated filings.



Yes, typically the wider end of the eye goes up. This makes for the more secure hang. There were 'reversible' pattern axes made with hourglass shaped eyes that were equal on each end. These were designed to be flipped at each re-hanging to compensate for the greater wear on the toe.

One of the chores of the man who was a swamper in the lumber camp was to limb the fallen trees. This often involved work closed to the ground. Their axes were frequently damaged and abused. Also, a swamper pattern axe was sometimes made thinner specifically for the task of limbing where a fine sharp axe is handy and there's no real need to pop the chip.

A feller might likewise use one side of his axe to bark the tree, work that might expose the edge to abrasive dust. This edge would have a little wider bevel. The other side would be filed finer for efficient chopping.
Click to expand...

I find more swamping patterns than others when I stop places or ask where local vending occurs. Enough that they have to be pretty full for me to pick them up.
They are underrated in some ways. Maybe one reason is that they are on the long and thin side. If you can find one with the bits intact and a little bit of cheek they are nice.
The one I grew up with was a Plumb Victory. I didn't like it just because it meant I had to do work.
No name Swamping example:
78357D84-F50C-41EC-88CA-DA3BFCCAD7E6.jpg
 
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