The right tool for those 1/8" bits is a Rotozip or other brand of spiral saw. A palm router would be fine if it has the right collet bushing. Do not attempt to use them in your Hitachi router. The router is too heavy and you will snap those bits in a NY second. It is not safe to stack collet bushings, they will seperate. Remember that even with their tiny diameter they are still spinning at close to 20,000 RPM.