Rockler's 8mm Dovetail Router Bit Upgrade

As you've probably noticed, there are two common sizes of router bit shank, and two common sizes of router collet: 1/4" and 1/2". Why?

A larger diameter shank is necessary to safely carry the mass of a large router bit. A large diameter shank is also less prone to vibration and consequently tends to yield a smoother cut. In certain applications, on the other hand, a 1/4" shank is either necessary or all that's required. The shank of a dovetail bit, for example, has to be narrow enough to fit through the opening in a guide bushing if it to be used with a standard dovetail jig.

Is there anything magic about the 1/4" and 1/2" inch diameters? Of course not. They're just handy standard sizes to use so that everyone has bits with the same diameter shank in their toolbox. It's a great system and we wouldn't mess with it unless we had a very good reason - which brings us to Rockler's 8mm Dovetail Router Bit Upgrade.

In a delicate operation like cutting dovetails, where precision really counts, you want every advantage possible. By adding 25 percent to the typical 1/4" shank size, Rockler has come up with a dovetail bita that produces a consistently smoother cut, but still fits comfortably inside a standard guide bushinga. The kit comes with the three bits used most often for dovetailing and an adapter that fits in a 1/2" collet. It's a small investment that's likely to have a big impact on your dovetail cutting accuracy.