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3 way miter joint

buckhuffman's picture

3 way miter joint (post #170352)

I've put the design for the 3-way miter joint into Sketchup.  I'm planning on printing this next week on a 3d printer (gotta love access to academic research).  Can somebody check my work to make sure I'm on the right track.  Once I've got a printed template I'm planning on doing this in my guild shop.




Attached file needs to have a skp extention

DaveRichards's picture

Well, they are all classed as (post #170352, reply #1 of 5)

Well, they are all classed as solid by SketchUp although I wonder why you have a combination of components and groups. Do you really want that little point sticking out there at the corner?

3way-joint.png31.71 KB
hkc94501's picture

Another Sketchup model (post #170352, reply #2 of 5)

The model Buck posted had some small problems at the very points of the miters so I did another that avoids the problem.

The probem is that Sketchup doesn't let you push/pull past an crossing line.  This makes it difficult to draw the compound miter angles.  You have to figure out where all the verticies of the intersecting planes are and draw in the intersection lines then erase the lines that define the portion to be removed.  You need to be careful to maintain the 3d integrity of the result but I think I got it right.  All of the miters come together in a nice single pointed corner.

I drew all of the components using a 1/7 ratio for all parts.  Which is to say that all of the dimensions are a multiple of 1/7 the thickness of the stock.  These proportions may be a bit different from the original article but it has the advantage that you can scale it for any stock thickness.  Unfortunately I did the drawing for 5cm stock rather than 7cm stock so the measured dimenstions will probably look rather strange and its too late to go back and change everything.

3dMiter.skp20.12 KB
hkc94501's picture

v 2. Fixed a bug (post #170352, reply #3 of 5)

Sorry there was one mortise missing from the red rail.

It's in there now but I haven't figured out how to persuade Sketchup that it is really goes through the solid. All the lines are in the right places but you can't see through the mortise as you should for a through mortise.  Either Sketchup doesn't like intersecting things at other than 90' angles or (more likely) I just haven't figured out how to do it correctly.




3dMiter.skp22.16 KB
DaveRichards's picture

How's this look? (post #170352, reply #4 of 5)

How's this look?

3dmiter_0.skp24.77 KB
forrestb's picture

Is this what you want (post #170352, reply #5 of 5)

I just extended the 4 corners of the red "box" out beyond the blue surface (why was the red box open at the bottom?)

I put a box on those extended lines and deleted the over-extended lines.  You should then edit the blue arm to show a hole.

Measure the distance out from the blue and move the red surfac in to the desired reveal.


3dmiter_0-2.skp27.57 KB