A standard corner rounding bit can work in two dimensions – the table (also known as the router base) runs along the side of the workpiece while the bearing controls the cut depth so it rounds over your square corners.
However what happens when you have a compound curve, which is common in wooden toys? You may come across a concave section, and there is no way you can get the router bit to that section. You may try sandpaper to match the curves and radius.
This is where the 3D Corner Rounding router bit comes into its own. Amana Tool®'s Industrial Quality 3D Corner Rounding Bit works brilliantly. Instead of having just a bearing on the end, this bit comes with a sleeve (that also spins) restricting vertical movement. The benefit of this tool is that you can use the bit above the table without the need to rest the workpiece on a flat surface.
This is no ordinary corner rounding bit. A guide ring on the bit perimeter coupled with a guide bearing above the profile allows you to round the edges of stock that curves in two planes. Just what’s needed for shaping chairs or any furniture that has compound curves.
Available here from Toolstoday.com, manufactured by Amana Tool.
Originally Posted by Stu on April 27th, 2014.
Read the original blog here.