[JerryBurks]

So, I started a new software project, this time to machine void free finger or box joints. Such joints in general are easy enough to do on a CNC but due to the bit radius usually require dogbone fillets to avoid interference. I wanted to avoid that and have the option of varying decorative finger patterns including true half-blind joints. I started about a year ago and gave up because I could not figure out the algorithms for creating the tool paths (my trigonometry is not up to snuff, I guess). Lately I picked it up again and had some success. The user interface is almost done (see below) and I am in serious debugging mode. I made a few test cuts and will probably try a complete box over the weekend. If everything works out I will probably publish a Beta version in a few weeks. I am quite happy with the result so far.




Toolpath simulation (using other CAM software):


Practical result (I need to flatten the boards better to avoid the gaps):


Another test:

[Khalid]

Brilliant Your designing and programming skills are at par excellence.

[CarveOne]

That's a complicated looking joint with lots of glue surface. I like the looks of both versions. Maybe even a random length pattern. Looks like your software can do it. I like that it's all cut in from the flat side of the material. Nice.

[JerryBurks]

Thanks! Yes, the surface is quite convoluted but that is necessary to be able to do it with a single cut of a ballnose bit. And it was the reason that it took me so long. The 3-dimensional relationships of the internal surfaces are not exactly trivial. Optimizing the toolpath so that it does not take forever to cut was another challenge. Such a joint takes about 8 minutes on my machine with an 1/8" bit for both sides. The second joint in the previous post was done using a 1/4" bit and went a little faster. The speed limit is really the bit flex for small bits. I broke a few when experimenting. The following picture is the actual tool path for the joint on the first picture.

[wizard]

I like that the joints look good! Sometimes looking good is just about the most important aspect of a design.

Just out of curiosity how long does I take to do a joint like that on your machine? I'm imagining a bit of carving to get those profiles and tiny step overs.

As for the software is it Windows based? Linux or Mac OS possibly?

[wizard]

Thanks for reading my mind as I typed and answering my questions. 8 minutes actually seems to be pretty good from what I can see.

Thanks! Yes, the surface is quite convoluted but that is necessary to be able to do it with a single cut of a ballnose bit. And it was the reason that it took me so long. The 3-dimensional relationships of the internal surfaces are not exactly trivial. Optimizing the toolpath so that it does not take forever to cut was another challenge. Such a joint takes about 8 minutes on my machine with an 1/8" bit for both sides. The second joint in the previous post was done using a 1/4" bit and went a little faster. The speed limit is really the bit flex for small bits. I broke a few when experimenting. The following picture is the actual tool path for the joint on the first picture.

[Devastator]

This is really cool! Love the rounded fingers.

[cncadmin]

I love it..just in time as I'm build my own cabinets and need draws.

[JerryBurks]

I love it..just in time as I'm build my own cabinets and need draws.

Oh my....no pressure

But I am making good progress with the debugging. Cut my first real project over the weekend. Since it is not totally reliable yet I used plain 1/2" BB plywood. Next project will be prettier lumber.
Focus is now on specifying the drawer or box dimensions and create the gcode for the whole job, i.e. cutout for the board sides, slotting/rabbeting and making segmented lids.

[billwh]

I love it. Very nice looking joints. All I need now is a CNC to do my own.

[JerryBurks]

..... Maybe even a random length pattern. Looks like your software can do it. .....

Hello CarveOne, thanks for the suggestion. I added a "Randomizer" button. If you hit it a couple of times you may end up with a good looking pattern. Most of the time they just look weird but maybe even that is useful.

[Devastator]

Hello CarveOne, thanks for the suggestion. I added a "Randomizer" button. If you hit it a couple of times you may end up with a good looking pattern. Most of the time they just look weird but maybe even that is useful.

Friggin awesome is what it is. It looks like two pieces of wood that have been fused together via the "Philadelphia Experiment".

[JerryBurks]

I finally launched the finger/box joint software for public consumption. If you are interested in such stuff you can find more information here.

Some more demo samples that I did lately: