 |
| Tapered fingers |
 |
| Mating side |
Advantages:
This joint was not easy to create the toolpaths for. It took drafting skills I learned in high school and the great drawing tools in my CNC software to create. Tips of the fingers are the same width as the valley between them. One half fills the center area left by the other half. The tapered sides were accomplished with a 3 degree tapered end mill. It has a 0.125" diameter tip, 3 degree tapered sides, and just a little over 1" of cutting depth.
I'll use this joint for top and bottom zebra wood caps on 1.5" diameter cherry dowel legs. Applications are anywhere you want to join round wood parts end grain to end grain. Only limited by your ability to clamp parts vertically within your CNC cutting limits. If you do use this joint please consider referring those who see it back to this post.
With straight cut finger joints there is always a conflict of fit. A battle of wit. Too tight and the fingers may not fit together at all. A perfect match and while they do fit together they are a challenge to assemble and any glue in the joint gets scraped away when you do assemble them. Make the joint looser and you have a loose fit that glue ends up filling across gaps. By CNC cutting with 0.001" accuracy the fit of these tapered joints is both easy to apply glue to and assemble, and will go together tightly with even contact between inner surfaces.
 |
| 3 degree taper between fingers. |
Comments are encouraged and welcomed.
4D
4 comments:
What model is the 3 deg tapered endmill?
SGS 32307 2500 3 DEG
Thank you. Do you think this taper could lock well enough by itself to use as a temporary connection for knock-down furniture, or would it need extra help (e.g., key wedge)? --Stephen (@craftsbotship)
As a "temporary" connection for vertical parts with the help of gravity then yes. But as wood expands and contracts over time the fit will likely loosen unless glued together and properly sealed. I like tapering tenons and mating tapered mortises not for how snug they are when pressed together, but rather because they are always easy to slide together and only get tight when fully inserted. Glue or a screw to pull them in still are needed to secure the joint. 4D
Post a Comment