I drew my dados as rectangles. How do I turn them into centerline cuts? (Dado Toolpath Creator gadget)

What it is

When you lay out a cabinet side, it is natural to draw each dado (housing joint) as a rectangle showing where the shelf goes. For cutting, the library page points out it is more efficient to use a bit of the right diameter and run a profile cut along a center line. Dado Toolpath Creator automates that conversion. It takes pre-selected rectangles, creates the center lines for the tool size you choose, and can create the toolpath in the same step.

The official manual has no dado tool of its own, so this gadget is the packaged way to do it.

Steps

1. Download the version 12 build from the gadget library and install it with Gadgets > Install New Gadget.
2. Draw each dado as a rectangle and select them all.
3. Choose Gadgets > Dado Toolpath Creator.
4. Fill in the form:

• Tool: the bit that will cut the dado.
• Toolpath: the name for the new toolpath.
• Dado Depth: how deep to cut.
• Layer Name: the layer where the new center-line vectors are placed.
• Allowance: an allowance added onto the dado.
• Create Toolpath: tick it to get a toolpath as well as the vectors.

5. Click OK, then preview the result.

Limits and judgment

• It expects rectangular vectors. Curved or angled housings need to be drawn and toolpathed by hand.
• The method is built around a single pass down the center, so it suits a bit close to the shelf thickness. When the stock is thicker than any bit you own, pocket the rectangle instead.
• Plywood is often thinner than its nominal size. Measure the actual shelf stock and test the fit in scrap. Use Allowance to tune a joint that is too tight or too loose. The public page does not say which direction a positive value moves the fit, so confirm it in the preview and on scrap.
• The center lines are regular vectors on their own layer, so you can leave Create Toolpath off and build your own profile toolpath on them.

Pro tips

• Name the layer something obvious, such as Dado Centers, so the lines are easy to hide when you toolpath the part outlines.
• Cut dados before the outline profile so the sheet is still held firmly.
• See the entries on joinery fit for how much clearance sheet goods usually need.