Q:How do you keep a router from grabbing and cutting out of line when feeding it along only one guide?
A: Half the battle of using a router effectively and safely is knowing which direction to feed it into a cut. To figure this out, you first need to be clear about which direction the bit is spinning … then feed the router the opposite way. This is true for both handheld and router table operations.
Heavy cuts should always be made against the router bit’s rotation. Holding a router over a workpiece and feeding the base against a clamped fence — the bit spins clockwise (imagine looking down through the router with X-ray vision). So, in order to feed against the bit’s rotation, start the cut on the left edge of the workpiece and feed to the right. You’ll know you’ve got it nailed if you feel a constant, controllable resistance as you push the router along. On the other hand, if you start from the right edge and feed left, the bit’s clockwise spin will allow it to pull through the cut and veer off course, away from the fence. It will feel grabby and unpredictable right away. Some woodworkers use these sorts of “climb” cuts to shear off the last bit of burn or gnarly grain from a cut, but climb cutting is only safe to do on very light, cleanup passes.