To Split or Cut the Kerf.

[FortyTwoBlades]

Once again some great discussion however if you think about the bottom of a kerf, the wedge should not be able to be driven that far, it should do its job before that point and never quite reach it. In my experience, if it does, then the wedge should be thicker because either the wedge or the sides of the kerf are compressing enough to allow the wedge to bottom out. That should not be allowed to happen and there is no real advantage in having it bottom out. Sure there is the argument that filling that little void is the ultimate but for the percentage difference it makes to the overall effectiveness or resilience of the axe, it is negligible.

And if you took a wedge that was able to bottom out in the kerf at full appropriate depth and drove it into a split you'd end up driving it too deep and probably crack the haft.

At any rate, the method doesn't matter so much, ultimately, as the end result. If you can haft an axe securely with either method without resulting issues then who cares which method you used?

 

[Oxbow]

Functionally, I would say a similar sized sawn kerf vs split kerf would be identical. The issue for me is how incredibly easy it would be for the split to continue past the 2/3 eye depth and ruin or weaken the handle before it was ever hung. For me, using the saw is so much more controllable that I would never consider splitting one. It would be a viable technique for fitting a handle in a bushcraft situation, if you're into that kind of thing.

 

[rjdankert]

Hum...

Well, here are my thoughts.

When you split wood with a wedge, the outward pressure pries apart the piece along the long grain fibers.


When a wedge is put in a handle the outward pressure is resisted by the eye of the head.


At some point when driving the wedge into the handle contained in the eye, an ideal point of resistance will be met. This point of resistance would be enough pressure to keep the head on, but not so much as to affect the eye wall.

A thick wedge will meet this point of resistance sooner than a thin one. That is it will decrease the outward pressure of the wedge sooner. So there is no leverage left to split the handle.

As far as the split vs sawn question goes I don't know. It sounds like some may pre-split the kerf. I've not seen this method. The method I have seen is where the kerf is just started enough to get the wedge started. The wedge splits the wood as it is driven in.

 

[Square_peg]

The issue for me is how incredibly easy it would be for the split to continue past the 2/3 eye depth and ruin or weaken the handle before it was ever hung.

This is where the risk is - before the axe is hung. Once hung the eye controls the split and prevents it from spreading. A well-fitted haft should be snug in the bottom of the eye.

I've used both methods and consider splitting the kerf to be a fall-back method when a saw is not available. If splitting the kerf there's no need to split it deep. Just get it started and the wedge will do what it needs to when you drive it. Less risk that way.

Once again some great discussion however if you think about the bottom of a kerf, the wedge should not be able to be driven that far, it should do its job before that point and never quite reach it. In my experience, if it does, then the wedge should be thicker because either the wedge or the sides of the kerf are compressing enough to allow the wedge to bottom out. That should not be allowed to happen and there is no real advantage in having it bottom out.

Good point. And let's be clear. A wedge that bottoms out has been stopped by the kerf not by compression so it has not filled the eye tightly and it is not doing the job it's supposed to do. Your wedge should NEVER bottom out.

 

[quinton]

This is where the risk is - before the axe is hung. Once hung the eye controls the split and prevents it from spreading. A well-fitted haft should be snug in the bottom of the eye.

I've used both methods and consider splitting the kerf to be a fall-back method when a saw is not available. If splitting the kerf there's no need to split it deep. Just get it started and the wedge will do what it needs to when you drive it. Less risk that way.




Good point. And let's be clear. A wedge that bottoms out has been stopped by the kerf not by compression so it has not filled the eye tightly and it is not doing the job it's supposed to do. Your wedge should NEVER bottom out.

My goal is to have the wedge stopped by compression just as it touches the bottom of the kerf.. .

 

[300Six]

With a split kerf presumably you would use a sharp tipped wedge which by nature is more fragile and prone to crack/split/break as it is being started and partially driven in. At least with a saw cut kerf and a wedge tip trimmed to the same thickness you have a more rigid 'go' at starting and setting the wedge intact during the first few mallet blows.

No one has brought up the topic of wedge 'purchase' in this thread. At a microscopic level splits are smooth finish whereas saw cuts are very rough; consequently there would be inherent way more grab (purchase) by a cut wedge in a cut joint than there would be a split wedge in a split joint.