VCarve Inlay - Rapid , Accurate, Versatile, and Easy to use
- Arbitrarily fine detail (not limited by bit diameter)
- Create multiple inlaid pieces simultaneously
- Fast cutting using standard bits
- Eliminates handling of individual pieces
- Inlays with hundreds of pieces in less than an hour
- Sharp interior and exterior points
- Eliminates traditional "bit offset" and associated CAD work
If you wish to follow along with this process, download your
Free Vectric Trial Software here (no registration required).
How VCarving Inlay's works
VCarve Inlay Technique in American Woodworker Magazine
: Aug / Sep 2011
VCarve Inlay makes beveled inlays using a V bit to carve both the inlay and the inlay pocket. It is VCarve Pro's unique ability to correctly handle the bevels on lines, arcs and points that allows the inlays to be cut without bit diameter offsets encountered with traditional CNC inlay techniques.
The resulting inlays rest in their respective pockets by contact along the sides of the inlay and pocket. This creates extremely accurate inlays showing little or no gaps between materials and rivaling the very best hand made inlays.
The versatility of VCarve Pro allows both pocket and inlay to be cut using the same design and same V bit but with simple differences in parametrics between the cuts. The optional use of an end mill may be useful to further reduce production time by hogging out large flat areas. (This capability is already native to VCarve Pro.) Note that additional CAD work, such as compensation for bit diameter, is not required.
The inlay itself is created with a backing which provides a base for multiple and otherwise fragile parts.
Choosing the Inlay Depth
The inlay geometry is shown below. This diagram is provided for reference only; you do not need to understand the diagram to make VCarved inlays.
Click for larger diagram
Typical values for the depths are:
- Inlay Flat Depth = 0.2"
- Inlay Start Depth = 0.1"
- Inlay Pocket Flat Depth = 0.3"
(Note that these values assume that the pocket
at least 0.4" thick
and that the inlay
material is at least 0.5" thick.)
These values will ensure a tight fit on the sides and leave a 0.1" gap between the inlay and the pocket bottom which will be filled with glue. They provide a large margin for error and final sanding. At the end of this process, the inlay backing
(which may be holding many parts of the inlay) will be removed. The final inlay and the inlay pocket will be sanded flush.
For reasons that are rather complicated, it is important to use a bit whose height is at least as high as the deepest cut you will be making. In the example above, that would be a height of 0.4".
I had wanted to make some inlays with my ShopBot but there were two issues:
- The artwork has to be revised to accommodate the bit size and that would require a fair amount of CAD work for each inlay
- The resulting inlay would have rounded edges.
I remembered that people who do intarsia will often angle their blade and rotate the piece as they cut to make up for the thickness of the blade. The resulting pieces fit perfectly even though they fit on a bevel. Could one achieve a similar effect using v bits?
It came to me that I might already have the necessary tools, both hardware and software (VCarve Pro). Here is the process that I used:
- This test was done with a 90 degree bit (A 60 degree bit might have produced better results.)
- Pick a graphic. I used Inkscape (free on the web) to generate an outline of the graphic. ("Fit vectors to bitmap" is now an integral part of VCarve Pro; One could also start from a DXF file or even make the entire design in VCarve Pro.)
- Start VCarve Pro and import the path file.
- Check for open, looped or duplicate vectors and correct them if necessary.
- Copy the path; paste it; and, using the mirror function, flip it horizontally.
- Move it to the right to get it away from the original path.
- Now decide how deep you want the inlay to be. Keep it relatively deep to make the inlay piece less fragile. For this example, let's use 0.2 inches.
- Create a VCarve Pro tool path with the original path (the one on the left) using a flat depth of 0.2 inches. This will be used to create the pocket for the inlay.
- Now create a profile tool path 0.2 inch deep on the flipped path (the one on the right) using the Machine Vectors "ON" option and no tabs. This will be used to create the inlay itself.
- Cut the pocket into your base material.
- Cut the inlay into material that is thicker than the cut depth.
- Glue inlay (with backing) into the pocket.
- Clamp, clamp, clamp. This forces the sides of the inlay into each other. The sides will even distort slightly to make a perfect fit.
- Wait for the glue to completely set. I have ruined many an inlay by not waiting long enough!
- Cut off the back of the inlay (I use a radial arm saw). If you sand the backing off, be careful not to get the wood hot enough to soften the glue.
- Sand down the top of the pocket piece.
Here are the pocket and the inlay (left) and the inlay in the pocket (right).
The result of this method is that graphics (many? most?) can be used without alteration and that the inlay can have sharp points.
Paul Zank & Damien Durrant