For a reliable saber cut in wood or fiberglass, use these Rotozip 1/8 inch Saber-Cut wood bits. These bits are a great addition for anyone using a Rotozip rotary tool. ZipBit for a variety of materials, from wood to fiberglass.
Zip bits
Sabrecut series
Cuts through all wood, fiberglass, OSB, laminates, plastic and vinyl or aluminum siding