Can a cnc carve the edges of a board?

This is a strange question, I’m still saving for my Longmill and in the mean time all kinds of weird thoughts are entering my head.

I was wondering if its possible to carve the edges of a board to a specific profile. Like as if you were using the Longmill as a router table except you aren’t limited to router bit shapes and the edge detail can be any shape you want.

As an example if I wanted to cut out a circle, but I wanted the edges of the circle to have like a chamfer profile, but one that alternated depth to make sort of a wavy profile would that be possible?

I hope I’ve explained what I’m trying to ask correctly.

Thanks

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@mu1sic2ian3 It is possible with some limitations. Some of those limitations will come from the CAD/CAM software you choose. In VCarve, for example, you can use the moulding toolpath to create moulding profiles on the outside edges of shapes. You cannot undercut, but you can get around that sometimes by doing a double sided project. If you have profile in mind, post a pic of it. I, and others here, will see what’s possible.

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Thank you so much, I don’t have anything in mind yet. I just had a thought that you might be able to make a 3d object by cutting out slices of material and stacking them. I suppose if you had a slice that needed to be under cut you could flip it and cut it upside down so that the undercut becomes and overcut?

@mu1sic2ian3 VCarve has a slicing feature, too. It may be overkill if all you want is a moulded edge, but it really depends on the desired end product. I cut a lot of picture frames and use the moulding toolpath to create custom profiles. I’ve only done a couple of sliced projects. Vectric has a couple of videos on it on their youtube channel.

Not only CAN you do the edge of a board you can also do complex joinery, dovetail, box joints, angled box joints etc. By cutting a slot in your cnc router bed and mounting a moxon vise below the slot and perpendicular to the table bed you can clamp your work vertically and machine the edge of your board shaped material.

I use some software called joint cam which offers a graphic interface for your joint selection, but you can also do decorative carving in Caveco by identifying your work piece as the edge dimension of the board with the depth of the piece being however much of the board you choose to poke through the slot in your table.

One of my most frequent uses for my Longmill is dove tail and box joints, you can make quality drawers in a snap, square and true every time.

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Thank you for the response! This is definitely something I’m looking forward to! I assume you don’t need to clamp the work vertically if you are just doing box joints?

box_joint
If this is what you mean by a box joint you need to clamp vertically to get the inside corners square. Laying flat each inside corner will have a curve to it. A curve the radius of the end mill. They can be cut flat if you don’t mind dog bones.
interesting_joints
On the left you can see some pretty big dog bones that allow the joint to fit. On the right is some interesting joints you can do with combination of vertical and flat work.

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I’m so glad I asked. That first picture is what I was thinking about as a box joint yes. I guess I need to plan to make the slot and vice setup once I build my work bench as I would definitely like to be able to do joinery like this.

Are there any videos or threads that you know of showing how to set this up?

Grant’s setup can be seen here.
My setup can be seen here.
This long thread has a bunch of tables and might give you some inspiration on your table design in general.

As Grant mentioned in his post you definitely want to cut the hole in the table with the LongMill so it’s square to the machine. So plan for the hole in the table design and cut it with the mill.

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When using the vertical vice is it difficult to align the board so that the machine cuts in the right place?

This has been very enlightening!

Thanks everyone!

I have the regular touch plate and that works fine with a vertical board to set zeros. As far as the alignment of the board itself if the moxon vise is square it’s pretty easy to get the board square. My slot is really wider than it needs to be. If you look at my setup you’ll see a small block of wood that I attached in the middle to help with squaring the board. Grant’s setup is more reasonable and I imagine he can just put the board to one side and it’s correct. Not sure why I made mine so wide as it’s unlikely that I’ll dovetail a 30" wide board. :laughing:

On a side note I’m considering changing my table to a torsion box as I’ve had some issue’s with my spoil board this summer when it got real humid. After not using my machine for a bit I went to do something and noticed that my perfectly surfaced spoil board was not perfect anymore. A cut that just touched the spoil board in one place was cutting into the spoil board by a couple mm about 12" away. So now I need to figure out how to incorporate a vertical rig into a torsion box design.

@mu1sic2ian3 Since @_Michael keeps dropping my name :grinning:, I will jump in. He has posted a link to my set up. It is crude by comparison to others, but it gets the job done. I have a cleat running vertically the depth of the support piece. It is perpendicular to the table top. By placing the material against that, I know that it is parallel to the Z axis travel. To hold the material at the correct height while tightening the vise screw, I have a simple block that runs up and down on a t-track.

My process is simply to butt the material against the cleat, run the block up to hold the material at the height that I want it, then tighten the vise screw. I have a removable cover that, when I’m not using the vertical mount, covers the hole in the table. When I’m using the vertical mount, I just butt the cover up against the material to reduce the volume of shavings that fall through the opening. Finally I have a chip drawwer at the bottom of the vertical side. It catches the rest of the chips and is easy to empty.

I want to emphasize that my set up really is crude. I am in this as a hobby and, since I have a complete woodworking shop in my basement, I was able to put this together using bits and bobs that I had laying around. And, it looks it. :grinning:

Finally, all this said, to get back to your original question, I would not use this set up to put a chamfer around the edge of a circle. It would be much simpler and quicker to create the profile you want and use it to drive a moulding tool path.

Well thank you everyone, this info is invaluable to me.

I guess we did go off on a tangent from my original question. Yeah I figured that wasn’t the way to do what I was originally asking. But I am glad that the subject of joinery came up anyway as that is something I absolutely want to explore with my Longmill.

Thanks again all, its a little difficult to imagine how all this will get set up from your descriptions since I don’t have a Longmill yet, but I’m sure once I get mine built I’ll get a better idea of how it all works. And it sounds kinda fun to come up with my own method of clamping under the table. So yeah looking forward to it!