Making Dovetail or similar joint in CarvCo

Hi All,

Here is the challenge I have. I need these two pieces joined at 90 degree without them coming apart along the way the arrows are showing (So finger joint doesn’t work).

Normally this would be a dovetail joint but my three requirements are

  1. I want to use the CNC machine to make it happen
  2. I dont want my board B to stick out from the other side of Board A
  3. I only want to have the board horizantally (Dont have a way to do it vertically)

Is there any CNC joint that I can use to accomplish this.
If the only way is a joint that is similar to dovetail, I am fine with making the board B (knowing that the corder would have the small hole , for the bit to make the sharp angle)

My problem mainly is the board A, I am not sure how to use carvco to make this cut, which toolpath do I need to pick? I guess I could pick the profile, make sure there is no stepping down and my first cut will go all the way to my desire depth. I just dont know if this is a hack (even if it works) , I feel like Im missing something and there must be a better (“Right”) way to do this.

Any help is appreciated!

I didnt show well what i meant with board A and B, here is a slightly better picture.

Hello Moosa. There may be other ways to do this but the only way I can think of, without a vertical mount, would be to do a modified finger joint like this.

But of course you would need to add dogbones because you can’t make the square corners.

EDIT: In my pic you would need 12 holes for corner relief, 4 on each of holes in board B, and 2 on each pin on board A. The holes in board A could be done from the right side and only go half way through if you are OK with doing a 2 sided job.

@moosa Since you’ve said that your problem is mainly board A, can you tell us how you are cutting board B?

@gwilki now that you ask I feel like Im doing it wrong, but here is what I was thinking:

just something that looks like dovetails and profile around it.
I would satisfy my need for the parts not to come apart the way I described.
Am I missing something?

@_Michael you are right, I feel so dumb if I swap the A and B it would accomplish what I wanted. I always had in mind that Board B has the Fingers, you have the Board A with fingers and that does what I wanted. I feel so bad. Still would be good to know how to do dovetail but that solves my problem.

@moosa It’s not necessarily wrong, but you will not get those sharp inside corners as shown in your preview. With the 1/8" end mill, those corners will be rounded.

@moosa I have a Dovetail Guide if you ever decide you want to add a vertical mount to your machine. If that’s even an option, I don’t remember what type of machine you have. Just throwing that out there in case you have not seen it.

@gwilki that makes sense.
Do you know of the “right” way of doing the corresponding Dovetail for my board A (If my board B has the dovetail shown above)

From this response, im guessing Carvco cannot simulate it (But maybe I need to try using a dovetail bit with Profile and make sure to go deep before I reach my board and go all the way in one pass without stepping down? sounds hacky


I saw that @_Michael thank you for putting that together, at first I wrote this question on that thread but then thought it might derail that conversation so created a new thread, but great post!
I will definitely setup a vertical mount someday.

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That is what I do in my vertical setup. set the pass depth of the bit to be at least as deep as you want to cut and do it in one pass. I go slow for this, it’s kind of scary!

Also Vectric cannot simulate it either and my dovetails are just entered as end mills.

So if your board B has the dovetail profile, with the addition of inside corner holes, I think you could use the dovetail bit, full depth, to cut a U shaped profile in board A. It won’t be exact because the dovetail is going to bevel the middle section of the U shape which wouldn’t traditionally be beveled. When making the U profile I put the line half the bit diameter away from where I want the cut to be and then cut on the line. It’s easier for me to think in terms of the center of the bit I guess.

That makes complete sense @_Michael thank you very much!

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@moosa Excuse the delay in replying, Moosa. Just to clarify for my slow thinking, in your original pic, you want the tail on board A and the pin on board B, correct?

No Problem at all! That is correct.