Setting-up to Cut a Recess in a Trapezoid Using the Shopbot
by togo1919 in Workshop > Woodworking
2538 Views, 6 Favorites, 0 Comments
Setting-up to Cut a Recess in a Trapezoid Using the Shopbot
I recently had a need to place an aluminum panel in a trapezoid for a mantelpiece. I decided to use the Shopbot so I could ensure a consistent depth for the recess.
The attached video shows the recess being cut.
I do my work over at the Techshop in San Jose...
Start With a Trapezoid Image Which Has the Same Dimensions As the Piece of Wood
![Capture2.PNG](/proxy/?url=https://content.instructables.com/FON/QLU3/HRPT1R3V/FONQLU3HRPT1R3V.png&filename=Capture2.PNG)
![image1.PNG](/proxy/?url=https://content.instructables.com/FAE/TD8M/HRPT1R3X/FAETD8MHRPT1R3X.png&filename=image1.PNG)
For preparing drawings for the Shopbot, I generally start with CorelDraw. Mainly because I'm most familiar with it.
The tool I used is called the Contour tool. I made a 1-step internal Contour, about 1/4" from the original.
Select the Object (trapezoid) --> Effects --> Contour. Alternatively, you can select CTRL + F9 to get the Contour tool.
The tool I used is called the Contour tool. I made a 1-step internal Contour, about 1/4" from the original.
Select the Object (trapezoid) --> Effects --> Contour. Alternatively, you can select CTRL + F9 to get the Contour tool.
Apply the Appropriate Contour
![Capture4.PNG](/proxy/?url=https://content.instructables.com/FRB/ZJV7/HRPT1RHH/FRBZJV7HRPT1RHH.png&filename=Capture4.PNG)
This process is pretty straightforward, especially since I wasn't worried about the colors or gradients or anything along those lines.
With the object (trapezoid) selected, I chose the following:
Inside
Offset - .25"
Steps - 1
Then I selected Apply.
And We Have Our New Trapezoid, a Quarter-inch to the Inside of the Original
![Capture5.PNG](/proxy/?url=https://content.instructables.com/FEI/K8U6/HRPT1RI5/FEIK8U6HRPT1RI5.png&filename=Capture5.PNG)
This is the new trapezoid I was looking for.
Now, CorelDraw allows you to separate the two trapezoids, but I did not want to do it. So, I went ahead and added a curve (set of lines) that matched the internal trapezoid to use for my eventual export. The next step shows this new curve.
Use the 2-point Line Tool to Make a Copy of the Internal Trapezoid
![Capture6.PNG](/proxy/?url=https://content.instructables.com/FYD/9YCR/HRPT1RO1/FYD9YCRHRPT1RO1.png&filename=Capture6.PNG)
I drew lines from node-to-node on the internal trapezoid. I changed the color to red to make it easier to see.
This curve is the shape I needed to export to VCarve to prepare a file for the Shopbot.
I could have simply ungrouped the Contour pair (probably saving some time), but chose not to do so.
This curve is the shape I needed to export to VCarve to prepare a file for the Shopbot.
I could have simply ungrouped the Contour pair (probably saving some time), but chose not to do so.
Move the Red Trapezoid to a New File, and Export for Vcarve
![Capture7.PNG](/proxy/?url=https://content.instructables.com/FS7/8CL1/HRPT1RPK/FS78CL1HRPT1RPK.png&filename=Capture7.PNG)
I opened a new file and added this new trapezoid.
I then went to File --> Export --> Save as Type --> DXF (using the AutoCad R10 option)
I then went to File --> Export --> Save as Type --> DXF (using the AutoCad R10 option)
I Opened VCarve Pro to Get Ready for My Drawing.
![Capture8.PNG](/proxy/?url=https://content.instructables.com/FXO/OQWD/HRPT1RR8/FXOOQWDHRPT1RR8.png&filename=Capture8.PNG)
I set the following in VCarve Pro for my piece to be cut.
Job Size
Material Thickness
XY Datum Position
Units
This data matched the piece I was using - your needs may be different.
Job Size
Material Thickness
XY Datum Position
Units
This data matched the piece I was using - your needs may be different.
I Imported My Trapezoid
![Capture9.PNG](/proxy/?url=https://content.instructables.com/FZH/4WXG/HRPT1RRV/FZH4WXGHRPT1RRV.png&filename=Capture9.PNG)
![Capture10.PNG](/proxy/?url=https://content.instructables.com/FAR/YD57/HRPT1RS9/FARYD57HRPT1RS9.png&filename=Capture10.PNG)
File --> Import --> Import Vectors
I selected the dxf I created in previous steps.
And I Prepared a Toolpath
Once I'd imported and moved the trapezoid onto the VCarve canvas, I created a toolpath.
Since I was using a 1/8" router bit, I used this info to set up the Pocket Toolpath, and carved down to 1/8".
The output file was a Shopbot Arc (inch)/with speed .sbp file.
Since I was using a 1/8" router bit, I used this info to set up the Pocket Toolpath, and carved down to 1/8".
The output file was a Shopbot Arc (inch)/with speed .sbp file.
And I Cut My Recess.
After aligning my piece and testing the alignment with some sacrificial pieces, I was able to cut a very nice recess.
I had to use a knife and chisel to complete the corners which had a 1/8" radius, since I wanted sharp corners.
I had to use a knife and chisel to complete the corners which had a 1/8" radius, since I wanted sharp corners.