In our last instructable we showed you how to make a heart shaped wooden box, so this time we thought we'd show you how to draw any shape box that you want.
We use Inkscape to do all of our drawing, it's free, open source, cross platform and most importantly really good, download it now and give it a try.
All of these boxes have been sized to fit into a single A3 sheet and can be cut on a machine such as the Blacknose A3 Laser cutter. We have shared them in pdf, dxf and the original svg so you should be able to open them in any software.
Step 1: Making the Outline
First switch inkscape over to outline mode. "View->Display Mode->Outline Mode". This will let you see the actual lines that are going to be cut and it will not show you the line widths or colours of the lines, those things are unimportant at the moment.
Then draw your box shape at the desired size, in this example we've chosen to draw a simple egg shape. Draw a circle on the page using the circle tool, this will be drawn as an object. Inkscape knows that the circle object has a radius and start and stop points but this needs to be converted to a path before it can be made egg shaped. Inkscape understands a path as 4 nodes with curved sections between them. "Path->Object to Path" will turn the circle object into a path. We made the egg shape by pulling the top node of the circle upwards, distorting the original shape.
Inkscape can calculate how long this path is and tell us how long to make the flexible edge strip that goes around the outside of the box. "Extensions->Visualise Path->Measure Path". A "Measure Path" dialogue box will open, make sure the "Length Unit" is set to "mm" before you click the apply button. The measurement value will appear on the path.
Change the length of the flex section to be the right size for the outline of the box. You can stretch the or shrink the flex but you will get better results by actually adding or removing lines from the flex. You can also set the height of the box at this point.
Step 2: End Caps and Lids
For this step you're going to need some copies of the original shape, you can do this with the traditional "copy and paste" method and then realigning the newly created shapes but Inkscape also has a duplicate function ("Edit->Duplicate" or "Ctrl-D") which is very useful here. Duplicate creates a copy of the original in the same position as the original. In outline mode you can see when there are multiple objects because the lines appear darker.
Select the first shape and change the stroke width to the material thickness. In our example we used 2.7mm poplar plywood, available from Kitronik, so we set the stroke thickness to match the material. Select the second shape and set the stroke width to 10mm + the material thickness, in our case 12.7mm. This will create a lip on the top of the box that is 5mm thick, if you want a thicker lip don't forget to double this value when calculating the stroke width. The dotted outline for the shape will be larger than the shape but the shape will appear the same because outline mode does not display line thickness.
To create the appropriate outlines you need to convert the stroke to paths this time. "Path->Stroke to Path" will create 2 lines for each shape, one on the inside and one on the outside. These need to be broken down again to make 4 separate lines "Path->Break Apart" will give you 4 concentric rings. We have labelled them 1-4 in the diagram.
These are all the shapes you need to assemble a box. The final diagram shows the 5 panels you need to make to create the caps. The box is cut and assembled as per the other instructable. In our files we have optimised the layout slightly to reduce the material wastage and to make it fit into an A3 sheet. Switching back to display mode ("View->Display Mode->"Normal") at this point will allow you to set the colours for the different cut operations.
Step 3: Go Forth and Make Boxes
This technique can be applied to form lots of different shapes. So far we have made square boxes with rounded corners, egg shaped boxes and heart shaped boxes. We can't wait to see what designs you come up and please feel free to show us what you do make, don't forget to tweet us a pic https://twitter.com/addsharks.