CNC Cut Dovetails

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Forum topic by Ger21 posted 09-02-2014 01:46 AM 5522 views 1 time favorited 26 replies Add to Favorites Watch
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1047 posts in 2555 days

09-02-2014 01:46 AM

Topic tags/keywords: cnc dovetails router

This forum seems to be pretty quiet, so I thought I’d post some pictures of what I’ve been working on for the last year. I’ve been writing a program to create g-code for cutting dovetails on a CNC Router. No additional CAD or CAM programs were used. Just enter a few parameters, export the g-code and cut.

With a CNC, you’re only limited by the size of the tool. Dovetails can be any size, any width, any spacing.

Here are some samples I’ve been making for testing.
In the first pic, all the pins and tails are different sizes.

-- Gerry,

26 replies so far

View klw's profile


17 posts in 1785 days

#1 posted 09-02-2014 02:09 AM

Can you share any info on tools, set up, and how it’s actually done? That would be very interesting…


-- I don't remember being absent minded...

View ,'s profile


2387 posts in 2971 days

#2 posted 09-02-2014 02:28 AM

I’m all ears… First though, let me say very nice job.

We are only in our first couple of months with a CNC and have been flat cutting dovetail, but I cheated in that I rent out the Mozaik program. It works for us but I bet your deal is a ton cheaper.

Keep us filled in. Those are some really nice looking dovetails.

-- .

View TheFridge's profile


5683 posts in 910 days

#3 posted 09-02-2014 02:35 AM

They look as close to perfect as you can get.

-- Shooting down the walls of heartache. Bang bang. I am. The warrior.

View JayG46's profile


138 posts in 1283 days

#4 posted 09-02-2014 10:21 AM

Those do look absolutely beautiful.

It seems like the orientation of the piece would be an issue. For instance, cutting trough dovetails on a vertically oriented piece would be relatively straight forward (like you were using a Leigh jig), but if you had to do it on a horizontal piece, you would have rounded corners since you are using a spinning bit, correct? So if yo were working on drawer sides or a large case, could you still do through tails without a 5 axis machine?

-- Jay Gargiulo, Naples, FL "Once you understand the way broadly, you can see it in all things."- Miyamoto Musashi

View Ger21's profile


1047 posts in 2555 days

#5 posted 09-02-2014 11:52 AM

Can you share any info on tools, set up, and how it s actually done? That would be very interesting…


- klw

They are cut vertically. You need a jig or fixture to hold boards vertically, and the spindle needs to be able to reach past the boards by at least the tool diameter. Length of boards will be limited by roughly your table height, depending on the machine design.
For half blind dovetails, one board is cut horizontally, and both boards can be cut in one operation.

Ideally, you’d want a fixture with both vertical and horizontal fences. But you don’t need the horizontal fences for through dovetails.
If the fixture is permanent, or in a repeatable location, it’s simple to set up a work offset, so no zeroing is necessary, except for the Z axis.
My current router actually doesn’t have the ability to mount work vertically, so the samples were cut clamped to a block of wood bolted to my table.

In the samples, all the material is 5/8” thick.
The half blind joint uses a 1/2”, 14° bit.
The through dovetail joints were done with a 5/8”, 8° bit, and a 1/4” 2 flute upcut spiral bit for the pins. These happen to be the only dovetail bits I had. I need to order some other sizes and make some more test cuts.

I also use the 1/4” spiral to do roughing passes, removing the bulk of material before the dovetail bits are used. My homebuilt machine isn’t the most rigid, so this gives a better quality cut for me. The roughing passes are optional.

The software ouputs both ShopBot code, and generic g-code that works with Mach3, LinuxCNC, and many others.

While I guess you could use a 5 axis to cut these, my program won’t write 5 axis code. It wouldn’t be very cost effective to use a 5 axis machine for cutting dovetails.

Here’s a video showing how a test joint I did a few months ago.

-- Gerry,

View SPalm's profile


5249 posts in 3306 days

#6 posted 09-02-2014 12:12 PM

Hey Gerry,

Those look really nice. Your machine looks rigid enough.
Did you cut a slot in your table top? Or extend out the front?

Good job,

-- -- I'm no rocket surgeon

View helluvawreck's profile


22713 posts in 2291 days

#7 posted 09-02-2014 01:47 PM

That is some great looking dovetails.

helluvawreck aka Charles

-- If a man does not keep pace with his companions, perhaps it is because he hears a different drummer. Let him step to the music which he hears, however measured or far away. Henry David Thoreau

View brtech's profile


884 posts in 2347 days

#8 posted 09-02-2014 02:05 PM

Many CNC machines that hobbyists use have 8020 (or equivalent) extrusions holding up the table. You can usually adjust the setup so that the tool can travel off the edge an inch or so with the carriage staying on the rails. It’s easy to put some work holders to hold a board vertical for this process on the extrusion. The trick is getting the whole machine up high enough that all your work pieces fit. If all you are making are boxes or drawers, no problem, but cabinet parts might be a pain. Most the the machines I’ve seen have the bed pretty low to the ground.

I’ve seen some tables where the table top extends out a bit from the extrusion. You could fabricate a spacer to pad out the extrusion so you have a firm vertical surface to clamp to.

While my machine is currently out of service due to a complete shop re-org (and other projects seem to get in the way), I’ve adjusted mine to be able to do this. I’d like to try your code when I get it back on-line.

View dannelson's profile


181 posts in 1795 days

#9 posted 09-02-2014 09:21 PM

I’ve seen your posts on other forums but never a link to purchase. Are you planning to do so soon? I have done these in Vetric software before with a vertical jig, are yours cut the same way? Do you need a beta tester ? Awaiting your reply thanks Dan Nelson

-- nelson woodcrafters

View Ger21's profile


1047 posts in 2555 days

#10 posted 09-02-2014 09:54 PM

I ve seen your posts on other forums but never a link to purchase. Are you planning to do so soon?

Hopefully in about a month.

Yes, they are cut vertically. Watch the video I linked to above.

I think you’ll find this far easier than trying to do them in V Carve Pro. No drawing or CAD work needed. No need to figure out where the toolpaths should go.
Just enter the size of your board, and the size of the dovetails, and you get a preview of what they’ll look like.

Not looking for any testers. It’s pretty much ready to go right now. I’m just working on a manual, website, and tutorial videos right now.

-- Gerry,

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1727 posts in 1626 days

#11 posted 09-03-2014 04:46 PM

Excellent Job on the Dovetails…..

-- What we do in life will Echo through Eternity........

View DiggerJ's profile


69 posts in 961 days

#12 posted 09-03-2014 06:04 PM

That is a thing of beauty! And thanks for working with me on my cnc posts.

Is that the machine on your website?

-- Digger -- If you work long enough and hard enough to make it idiot-proof...the world will build a better idiot!

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1047 posts in 2555 days

#13 posted 09-03-2014 06:12 PM

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3940 posts in 1928 days

#14 posted 09-03-2014 06:20 PM

Beautiful and perfect. Can you post a video for us?

-- This is a Troll Free zone.

View Ger21's profile


1047 posts in 2555 days

#15 posted 09-03-2014 06:27 PM

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