How to create a two piece circle with tabs

[jeffreywolf]

My laser bed is 20" x 12". I want to create a circle that is 18" in diameter. To do this, I need to split the circle in two pieces that will be 18" x 9", but one piece will have 3 male tabs and the other will have 3 female inserts for the male tabs, so that the 2 pieces can be connected together to form the 18" round. Can anyone tell me how to go about accomplishing this? Thanks!

[Wyked (Chris Gallaher)]

Not sure how well I can explain this but here goes, Draw a line through the 18in circle, Draw 3 rectangles the double the thickness of your material x say 3in and place them centered on the center line where you want the Tabs/slots, then use node edit to get the semicircle shapes with tabs and slots. Actually easier to do than explain.
18in Circle.lbrn2 (15.4 KB)

[RalphU (RU)]

Here is a way to do it with dovetails. Each layer gets an outward kerf offset.

Draw a 18" diameter and place the center of it at:
Xpos 9.25
Ypos 9.00

Select circle, right click, and convert to path

Draw a 18" line

Draw a polygon

Change shape properties as shown

Position the center of triangle at:
Xpos 9.25
Ypos 9.00

Select triangle, right click and convert to path

Duplicate the triangle and move the duplicate 6.25" to the right

Duplicate the center triangle and move the duplicate 6.25" to the left

Highlight the 3 triangles and the line, and go into edit nodes mode

Trim out the tops of the triangles so it looks like this

Select the dovetail, and Auto Join Selected Shapes

Put a 0.125" radius in the corners highlighted

Duplicate the dovetail shape and the 18" diameter circle

Move the duplicated shapes 20" to the right

Move the duplicated shapes to the black layer

Go into node edit mode, and delete the bottom of the red circle and the top of the black circle

Select all and Auto Join Selected Shapes

Move black shape 20" to the left

Set outward kerf value for each shape

[MikeyH (Mike Hembrey)]

Excellent description of how to do dovetails!!!