# Compound Miter to mate dry fit joints



## breadlegs (Feb 23, 2013)

Hello. I'd love to pick your brains on this project im really confusing myself with.....

I am working on a round table project with joints that i hope can be un (de?) mounted . I am a newbie and have trouble cutting these joints on a miter saw ( let alone phrasing my question)... 

So the geometry is a bit complex (I have an architecture background) but think it would be sooo nice to join these components this way... the 5 legs would come together and slot into a rotational pentagram type shape. 

Not only would this require cutting a compound angle but i dont know how to get the angle of the plane on the inside of the joints correct. It has to be at an angle so that the parts fit properly. My first question is how would i produce dimensions for these cuts?. 

I can produce detailed angles from my 3d models but dont know how on earth to set them in wood. I have access to allot of tools a the Tech Shop in Detroit (cnc,miter saw, table saw, hand tools). Maybe if i could phrase what im trying to do better i would have a easier time working with the human resources at the tech shop. So my second question is what techniques would be best suited to do this? each angle woud have to be reproduced more or less the same on 5 identical components. 

The joins happen on 1X6's (or maybe furniture grade ply)









This shows the cuts from above (the 6" dimension of the 1X6")... about 37 degrees from perpendicular










Shows some of the thickness of the 1" dimension of the 1x6" this dimension is 22.2 from perpendicular. 









This image shows the assembly; the blue and red parts show the inside and mated slots of to components respectively 

Also does anyone have any examples of projects that have joints cut at angles like this? Do you any alternate ideas for joining these parts?

Thank you for reading... I really look forward to learning more about how to do this.


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## tc65 (Jan 9, 2012)

If you know all the angles, I'd probably transfer cut lines to the boards, cut them with a handsaw and clean them up/fit them with a chisel. Producing the cut outs shown in your second picture would be quick work with hand tools.


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## TooTightIsBroke (Feb 24, 2013)

Correct me if I am wrong , but it seems it would be impossible to assemble with nice tight joints. It seems you would have to work in a circle, one on top of the other, and when you got to the last one one, the first piece would be in the way of the fifth piece trying to mate on the fourth piece...blah. Make sense? You may have to split the fifth piece and re glue? As far as the angles... A lot of tinkering and test pieces.


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## breadlegs (Feb 23, 2013)

*re*

Thank you for the response. 

Yes... Ill give it a go with hand tools...Im worried about my accuracy this way. I've never used a chisel so yes that will take some tinkering. 

Im interested in speed, how I can reproduce the same angles & if there are any ways i could machine these in a mass production type way? The counter top will be made of 5 parts cut on a cnc router that fit together.

Thats also a good point about the parts getting in the way of eachother that i didnt address in my post... I've done the same thing with three components pinwheeling before and found when I flare the openings of the slots on one side and edge all the parts in at the same time... you can get them in... so will experiment with varying degrees of this.


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## TooTightIsBroke (Feb 24, 2013)

Mass production? Surely you could make jigs and use a dado setup. But the time required for that kind of troubleshooting (compound angles), may very become greater than the time spent chopping at those things, if your only going to make a few. And the cnc i am unsure of as i have no experience except for a couple sales demos, but i believe unless you have a high end machine those compound angles will not work. As far as chisels go, know that you will not get good results if they are not sharp. Brand new chisels are NOT sharp, you will need to sharpn them to at least 4000 grit before you produce manageable, quality cuts. Most guys go to at least 8000. Hopefully your shop has wet stones because they can be a bit pricey. For a good sharpening demo check out "askwoodman" on YouTube, he has a very detailed series, covering many things you won't even need. Flatten your sole, polish your bevel, knock off your burr. Simple enough.


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