I get chipping when I use my pattern-cutting bit on my oak rails and stiles., I’m using CMT bits in a Porter Cable 7518 router, mounted to the top-of-the-line JessEm router table and fence system. My local woodworkers’ supply store tells me the amount of chipping is normal with oak grain, but I never see this problem with pieces made at large cabinet shops. Is their equipment that much better? Do they make enough so they can discard the imperfections? Or am I being too much of a perfectionist? I’ve tried all the rpm settings and feed rates possible.
Michael Dresdner: You did not mention where the chipping occurs. If it is on the trailing edge, you might benefit from using a sacrificial backer block. Many times, chipping is less an issue of feed rates and rpm settings than it is of how the stock is fed. Feed it evenly and at a steady pace and the cut is smooth. Jostle it ever so slightly and you run into problems. Automatic feeders, common in many large shops, eliminate the problems caused by our human inability to run wood in a perfectly machine-like pace, with no variation in speed, pressure, or plane.
Rob Johnstone: It does not sound like the problem is your equipment, ; what you’ve described is top-shelf. I am not clear if this is a problem all the time or perhaps with a specific lot of wood. I’ve experienced significant variations within species. One bunch of oak will machine like a dream and other pieces will be just plain perverse. Is it only oak that is giving you trouble? Is it all the same bunch of oak?