Originally Posted by
Chip Lindley
Tom, if you look at a Shelix cutter head, each carbide insert is held in place by an allen-head set screw. The screw registers the insert. There is no other adjustment other than the tight tolerances built into the design and machining of the head, carbide inserts, and set screws. A cutter-full of bolted-on inserts has no adjustment other than to be shimmed exactly to be parallel with the outfeed table.
As Chris explains above, on a conventional cutter head, we assume the cutter head has been shimmed parallel with the tables at the factory, or after a rebuilding. When mounting knives, each can be raised up/down with jack screws to a desired height, parallel with the table.
Old jointers (before the marvelous jack screws) relied rather on trial and error, even with knife setting gauges pressed down on a spring-loaded knife to achieve exact (sorta) height. Then, the jib screws were tightened to secure the knife.
Very OLD cutter heads had no springs and relied strictly on trial and error to set the knife height! Those MagnaSet gauges are somewhat useful in holding those knives at exact height before tightening the gibs.
During all this knife-setting activity, shimming the entire cutter was not indicated. Only upon initial manufacture, or perhaps after new bearings were mounted, was the cutter head shimmed parallel with the table. Suffice it to say, the cutter head is shimmed (adjusted) only Once! The knives are adjusted every time they are sharpened and inserted.