There are a lot of situations where being able to round over both the top and the bottom of a workpiece can be extremely convenient and save a lot of time. Let's say you just finished making a stack of kitchen cutting boards for gifts and are now tasked with rounding over all the edges of each of the cutting boards. You could use a standard roundover bit and round over one face then flip the board over and round the other. But you can save time by using the Infinity double roundover and beading bits to rout both sides at once, cutting the work in half.
If you do any form of production work you can see how these router bits could really be a time-saver.
Unlike a traditional bullnose bit, these woodworking router bits can be expanded from a full half-round bullnose profile all the way out to rounding over both top and bottom edges of a workpiece up to 1-5/8" thick. If you want to create a bead profile on both edges at once, you can work with stock up to 1-7/8" thick.
These bits can be customized to rout profiles based on the thickness of the workpiece.  You can add or subtract shims to fine-tune the spacing between the cutters by as little as .003" at a time. The order of the shims isn't important as long as the bearing spins freely and the distance between the top and bottom cutter are correct for your project.
Each of these bits comes with two bearings so that they can be used to make roundovers, beads with up to a 1/8" fillet, and full beads with 1/8" fillets on both faces. Remove the bearing to make a true bullnose profile or a full bead. With these options for customization, each of these bits can act like several router bits in one.
The double roundover bits come in your choice of 3 different radii: 1/8", 1/4", and 3/8"-radius. The best part is, all three bits are available in a money-saving set (Item 00-390).
If you've ever assembled a project, like a chest of drawers or a table, and forgotten to roundover the bottom edge of the top, these bits can be a life-saver. (Don't ask me how I know this.) Just use the bit in your hand-held router to finish off that bottom edge. This is just one of the many uses I've found for these bits that prevented me from having to tear down the project to finish routing the edge.
Another reason to have the 3-piece bit set is so you can mix and match cutters to create a different radius on the top and bottom edges in a single pass.
You can combine the 3/8" and 1/4"-radius cutters to create a very traditional and attractive thumbnail edge detail on a tabletop or chest-on-chest. This is a common profile on Shaker-style and other types of furniture.
If you want to make a decorative bead for something like the front edge of a bookcase shelf, choose the 1/4"-radius bit and set it up to make a bullnose profile, as shown below. Rout the edge on a wide piece of stock, to create a 1/2" bead with a 1/8" fillet along the top and bottom, and then rip the edge free at the table saw.
We recommend these bits be used in a variable speed router set to a maximum of 18,000 rpm and are ideally suited for use in your router table.
