Inset Routing with a Shaper

Advice on how to rout a cavity into the middle portion a long piece of solid wood. July 29, 2011

Question
I am trying to find the correct way to use our shaper to perform inset routing. We need to take a long piece of solid wood and route a cavity using some custom made knives for a portion of the piece's length so it is not an edge shaping or side shaping operation. I have searched through four dedicated books on shapers and there is very little information on this process.

One says you should have your start and stop blocks and rotate your piece into the shaper cutter from the right side of the cutter head. Another book says never rotate your work into the cutter from the right side, but only the left. I am assuming regular, counter clockwise rotation of the cutter, looking from above the cutter head. Any suggestions regarding sources for examples? How deep a cut should one make in a single pass? The machine is a 3 HP Grizzly shaper with special ordered cutting head.

Forum Responses
(Solid Wood Machining Forum)
From contributor B:
A tall wood fence is affixed to the shaper with the knife just cutting through it. The end of the stock is placed against the stop (to the right) and then pivoted into the cutter until it is flat against the fence. The stock is then pushed forward until it contacts the other stop to the left. The board is then pivoted out from the right (one continuous motion is what you're looking for). A little tip - start with a slightly thicker board and run it through the thickness planer after you've made your stopped plow cut.



From contributor M:
Your shaper is reversible, so keep in mind you can go right to left or left to right at your preference. Just be sure you are feeding your stock into the rotation of the cutter or it can grab the part and launch it.


From the original questioner:
One book I read was correct and the other was incorrect. I am going to make a few test pieces to insure I get the hang of it. If you have any suggestions for resources for this kind of operation I would appreciate learning about them.