Router Compression Drill Compression Cutter is designed with upper and lower grooves. The upper portion of the cutting length closest to the tool holder has a left-hand spiral that forces the chips downward. When using a compression tip, you must ensure that the first cut is below the cutting part of the tip, otherwise you will not be able to use the compression tip. You will get similar results to using a cutting tip for a single cut. Guidelines for going deep into the material, dipping a distance rather than all at once, and starting from the outside of the design to the depth of fit ensure the entire piece is completely clean on top and downstairs. Compression drill bits are designed for a single cut, but if your machine can't handle this depth of cut, you can make multiple passes as long as the first pass is under the cut portion of the part. Industrial QualityMade of premium hard metal - Fast and clean engraving - Plastic bearings with dimensional information Suitable material for engraving, cutting, engraving, etc. on MDF, ABS, PVC, PCB, SMT, etc. Milling, grooving, engraving, CNC, acrylic, nylon, resin, plastic, MDF, wood, plywood, hardwood, etc. Ideal for 3D engraving, surface treatment, 3D relief sculpture, etc. Features: Flute: Both compatible with portable portable routers. Suitable for portable benchtop milling machines. Suitable for small CNC milling machines