Dovetails and box joints with CNC

[db113]

I know this is probablly a simple question for this forum but Im new to the CNC world. Im a woodworking hobyist and I became interested in CNC after exploring plans for making a Multi-Router see attached photo). The cost of the multi-router is too high to buy so I thought I could make one. As I began learning about linera bearings and began to collect parts to make a Multi-Router I began to see more and more about CNC. It occurred to me that a Multi-Router with CNC control would be a great project and a bif time saver in the woodworking shop.
I would like to know if anyone is using CNC to make dovetails and/or box joints or mortise and tennons. If so, what is your setup and can you describe the process.
Thanks
A woodowrker in Tennessee
db113@mindspring.com

[HenryCNC]

I remember seeing a setup on the ShopBot forum... If you have time, browse through there and see if you find it.

One of the boards is verticle and either attached to the end of the table (providing the cutter can reach it) or through a hole in the table.

If you come up with any good pictures please share.

Henry

[ger21]

Basically you need to incorporate a vise into your CNC to hold work vertically. Then it's just some simple gcode to cut dovetails or box joints.

[HansM]

I'm interested in doing this too. My plan at this point is to cut a slot through the bottom of my CNC table so the wood can come up from underneath. The CNC table is mounted on a wooden table. Then I would attach some sort of angle bracket under the table to clamp the wood stock to. This would leave just the end of the board sticking up into the CNC working area.

I actually have a very nice Incra fence on my (non-CNC) router table that makes it pretty easy to do excellent box and dovetail joints. But with the CNC I think I could do some unique things like heart-shaped "dovetails". Throw in some spades, clubs and diamonds and you wolud have some one-of-a-kind joinery for a game box!

Lance

[db113]

Lance, where have you been all my life?
It was good to find another interested in making dovetails and boxjoints, etc. on a CNC machine. Have you started a CNC machine yet? So far, Ive only collected the parts: motors, control boards, powersupply, breakout board, precission rails, Thomson bearings, ball screws and software. I hope to begin framebuilding in the next few weeks. This weekend Im planning to put power to my motors and work out any kinks in the electrics. I think your right about having something beneath the table (angle iron) to clamp the work pieces to. Also, the decrative joints (spades, hearts, diamonds, etc) would make some pretty sweet pieces. Lots of opportunity to be creative. Let's keep in touch with one another as we progress with this project.
Good luck

[HansM]

I do have a CNC router up and running! It's a shopmade machine built by a contributer to this forum, Coldfusion. Here's what it looks like:

Lance's CNC router

The base of my setup is a solid plate of 1/4" aluminum. My plan would be to cut a rectangle in the base about 12" x 2". I think that would give me pretty good capacity for end joinery without comprimising the strength of the table (I hope!).

I also posted a picture of some of my test cuts. I'm using both SheetCAM and MeshCAM. In the samples the hand is a DXF file, and the leaves were a bitmap.

Lance

[wjbzone]

If you have enough Z clearance you can mount your router horizontal. This isn't exactly a dovetail, but it looks good.

[db113]

YES!! Thats the idea.
What software are you using?
How 'bout a picture of the assembled box.
How tight are those joints?
Any other woodworking tricks with that CNC router?

[HansM]

Wow, that's funny you say that because I was starting to think the same thing! Coming up through the bottom of the table would limit the size of the boards you could work on, and also I think it would be awkward getting the stock in and out of there. My router has 9" of Z travel so I think that would be plenty for joinery.

So, I either need a spindle mount that can rotate (and lock) 90 degrees, or possibly just a second mount that holds the spindle in a horiz position and I could just remove the vertical mount from the gantry and and attach the other one when I wanted to cut that way.

Lance

[ger21]

Or even better, 2 spindles. One horizontal and one vertical.

[wjbzone]

Here is a picture of the assembled box, I stained the wood so the joints would stand out.

I use turbocnc to run the router. The gcode came from my gcodeout.lsp program using Autocad.

All the joints were cut using a 3/8 bit with 0.005" clearance programmed in the gcode. I had to press the parts together. Other then my depths being slightly off because the boards were not planed, the joints are tight.

Also here is a drawing of a fixture to mount on my table to align the edge of the boards for the dovetail. Have not built this yet.

[spalm]

Wjbzone, awesome! You one clever fellow.

I have been thinking of this quite a bit (pun) and wondering if a small program like Spirograph that would preview the pins and tails why generating Gcode would be helpful. Seems like you did not need it at all.

Good job,
Steve