Why selecting a relief and carving bit is a critical step
The word is spreading about our carving of reliefs and patterns in the local community. With this comes interest and the desire of woodworkers to see how their favorite wood types will respond when they are carved on the CNC router. We have up to date received 14 new wood types for carving. We appreciate this, great news! It has thus become critical to create a physical library of relieves that will show the response of each of these wood types. We know that the 1/8’ ball nose bit carves very detailed reliefs on a 100 by 100 mm area but the feed rate when carving harder wood could potentially be too low. We thus set out to select a relief and carving bit that will work together well enough to provide an adequately detailed picture while maintaining the speed when carving a 100 by 100 mm area.
Creating a baseline for selecting a relief and carving bit
It was a close call between cherry and beech wood types, European Beech was succesful as it really carves very beautifully. We selected 5 very detailed or smooth flowing designs, three from the Artcam Express library and two from our own library. We chose the 1/8′ ball nose suitable for its detailing level and the 1/4′ ball nose bit from Amana Tools as it is more robust and should handle the harder wood. The test was run at what we have determined as the optimum feed rate and set the router speed so as not to make powered wood shavings or burn the wood (Yes, it is very easy to burn the wood when you have a bit running at a couple of thousand rpm) or limit the burs, etc.
The next sequence of carved reliefs show the outcome when carving with a 1/8’ CNC bit. The relief is clear with very fine cutting line. The surface of the relief is also very smooth. When using 1/8’ router bit any of these reliefs would work very well for the testing the various wood types.
In the case of the ¼’ router bit, the next sequence show the outcome. The time it takes to run the relief is about half of the time required for the 1/8’ router bit. It is clear that the finer detail is lost although all the reliefs still look great. The surface of the relief now have very clear tool paths and the cutting lines are more clear over the total relief. On smooth carvings, this is not a problem as these will easily disappear with a bit of sanding and polishing. This becomes more of a problem where there s lots of detail, as you start removing some of the detail when remove the cutting lines.
All 5 these reliefs still look great but one is all that we can use based on the wood that was so kindly supplied. It was close between the owl, lion and dolphin reliefs. The selected relief and carving bit were the dolphin relief with the 1/4′ ball nose. The main reason being the ease of sanding and polishing. The actual tests of the woods you will find under each of the wood types.
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