Hey there, I'm new around. Been reading the forum for a while, posting just now.
This post sparked my interest ( http://www.bushcraftuk.com/forum/showthread.php?t=14284&p=746058#post746058 ). I'll be using the term dovetail joint this post (not sure if what I made is a true butterfly joint).
I've taken up (stick) carving recently, and I'm particularly interested in perfecting my dovetail joints for speed and repeatability.
I've found two sticks roughly the same size, and started carving with a stanely cutter. My choice of a small blade was driven by my lack of precision with bigger knifes, plus the mechanical advantage. Alas, my results are rather disappointing.
http://imgur.com/a/ORdRj#0
The first 4 pictures are the first piece. I've found out that the easy way to carve to triangles into the stick was to slowly, slice by slice, remove them out, since this was going against the grain, between two stop cuts. After some "ground" has been established, i could simply remove roughly triangular chips (like in pictures 11-13). This proved to be very ineffective in the end, because it reduced the overall section of the stick (should have been more like pictures 8-9, second stick), but the end result was "pretty", no rough chips or edges. When I tried carving on the other side, somehow I overshot the angles, and I only corrected it later (pictures 2-3).
The second stick proved more of a challenge. The first method would have eventually led to splitting the stick in half, each with a V side (when viewed from above), so I changed my strategy to carving only to half the stick "depth" (picture 8). This proved much more of a challenge then I initially thought, because I had to carve a trapezoidal shape through the stick, which becomes smaller and smaller as I approach the medulla (core?), rendering the characteristic dovetail shape. I resorted to my initial strategy, dividing the two triangles to be removed into small chips and removing them (stop cuts), and then chipping triangular pieces from the new surfaces, using the edges of the triangle as stop-cuts. In the end, I resorted to using a two sectional stop cuts (think leaning sides of the trapezoid) and two lateral stop cuts (one on each end of the dovetail), taking a few chips, deepening the stop cuts, taking more chips, and so on. The central (smallest) portion proved to be the most challenging.
In the end, the sticks match, but the only provide limited support. There's an obvious backlash, and only two of the four contact wedges fall in position when I push against them. Plus, as you can see in picture 10 (not sure if it's really obvious), there's only one wedge falling in place, while the opposite one touches over a much smaller area, so technically, there's just a single wedge out of the whole four taking the whole load. Very bad.
The thing is, I haven't found a lot of info on specific carving techniques for a joint, or the mechanics of a joint, and so on, and after some googling (there's only this particular thread -> that sparked my interest), I started thinking on my own. But obviously, there are better ways to do it.
My questions
a) Take the two triangles you have to carve 'out' on such a joint. What's the best technique to do it? I find that taking small chips through the stick is inefficient.
b) How should I align the angles so joint will hold on at least two (opposite) wedges under load? Ideally it should hold on all four. Any tips for increasing the precision?
c) What's a better method to carve out the inside section?
Ideally, a few pictures or a stop motion of the making of such a joint would be great.
Also, I'm not sure if my terminology is right (I'm not a native English speaker), so I'll try to explain what I've said here:
I called "chipping" removing a portion of wood with the grain. This has a rather smooth feeling in the wrist.
I call "stopcut" pushing the blade deeply into the wood, through several layers of grains. The idea is that, once I start chipping, it should stop at that specific cut, so I wouldn't be forced to bend the blade and propel the chip out. I have tried using long chips, and cutting them at the end, but this proves to be imprecise. Making stopcuts requires a lot of pressure to be applied.
This post sparked my interest ( http://www.bushcraftuk.com/forum/showthread.php?t=14284&p=746058#post746058 ). I'll be using the term dovetail joint this post (not sure if what I made is a true butterfly joint).
I've taken up (stick) carving recently, and I'm particularly interested in perfecting my dovetail joints for speed and repeatability.
I've found two sticks roughly the same size, and started carving with a stanely cutter. My choice of a small blade was driven by my lack of precision with bigger knifes, plus the mechanical advantage. Alas, my results are rather disappointing.
http://imgur.com/a/ORdRj#0
The first 4 pictures are the first piece. I've found out that the easy way to carve to triangles into the stick was to slowly, slice by slice, remove them out, since this was going against the grain, between two stop cuts. After some "ground" has been established, i could simply remove roughly triangular chips (like in pictures 11-13). This proved to be very ineffective in the end, because it reduced the overall section of the stick (should have been more like pictures 8-9, second stick), but the end result was "pretty", no rough chips or edges. When I tried carving on the other side, somehow I overshot the angles, and I only corrected it later (pictures 2-3).
The second stick proved more of a challenge. The first method would have eventually led to splitting the stick in half, each with a V side (when viewed from above), so I changed my strategy to carving only to half the stick "depth" (picture 8). This proved much more of a challenge then I initially thought, because I had to carve a trapezoidal shape through the stick, which becomes smaller and smaller as I approach the medulla (core?), rendering the characteristic dovetail shape. I resorted to my initial strategy, dividing the two triangles to be removed into small chips and removing them (stop cuts), and then chipping triangular pieces from the new surfaces, using the edges of the triangle as stop-cuts. In the end, I resorted to using a two sectional stop cuts (think leaning sides of the trapezoid) and two lateral stop cuts (one on each end of the dovetail), taking a few chips, deepening the stop cuts, taking more chips, and so on. The central (smallest) portion proved to be the most challenging.
In the end, the sticks match, but the only provide limited support. There's an obvious backlash, and only two of the four contact wedges fall in position when I push against them. Plus, as you can see in picture 10 (not sure if it's really obvious), there's only one wedge falling in place, while the opposite one touches over a much smaller area, so technically, there's just a single wedge out of the whole four taking the whole load. Very bad.
The thing is, I haven't found a lot of info on specific carving techniques for a joint, or the mechanics of a joint, and so on, and after some googling (there's only this particular thread -> that sparked my interest), I started thinking on my own. But obviously, there are better ways to do it.
My questions
a) Take the two triangles you have to carve 'out' on such a joint. What's the best technique to do it? I find that taking small chips through the stick is inefficient.
b) How should I align the angles so joint will hold on at least two (opposite) wedges under load? Ideally it should hold on all four. Any tips for increasing the precision?
c) What's a better method to carve out the inside section?
Ideally, a few pictures or a stop motion of the making of such a joint would be great.
Also, I'm not sure if my terminology is right (I'm not a native English speaker), so I'll try to explain what I've said here:
I called "chipping" removing a portion of wood with the grain. This has a rather smooth feeling in the wrist.
I call "stopcut" pushing the blade deeply into the wood, through several layers of grains. The idea is that, once I start chipping, it should stop at that specific cut, so I wouldn't be forced to bend the blade and propel the chip out. I have tried using long chips, and cutting them at the end, but this proves to be imprecise. Making stopcuts requires a lot of pressure to be applied.
