Eventually, planer knives get dull and nicked...then the fun begins.With a conventional cutterhead, each knife is held in a slot against a steel gib bar and a series of bolts.When it’s resharpened, it must be adjusted for proper height using jack screws underneath.The height of all three knives must match precisely to plane properly. It’s time-consuming but do-able if you’re really patient.
JET makes the job much easier by including self-indexing, double-edged knives on its JWP-15DX planer. Here, the knives fit over a pair of tiny pins on the cutterhead, which automatically set them to proper height. Once both edges are dull, you throw the knives away.
Powermatic provides a Byrd Shelical Cutterhead on the 15HH planer, with 98 square carbide inserts. Each locks in a pocket on the cutterhead with a Torx screw. Four sharp edges make it easy to remedy nicks: just give the damaged cutter insert a quarter turn and tighten it back down. No gib bars, bolts or jack screws here.