Appropriate Router Bit for Pocketing

Tooling advice for pocketing. August 16, 2012

I've been doing a lot more pocketing lately with upcoming projects and I wondered what the best tool to do this with is. I've heard of guys using their fly cutter and dropping it in at a 45, although I'm reluctant because it's not really meant for plunging.

Forum Responses
(CNC Forum)
From contributor M:
You are correct, a typical flycutter is not a plunging bit. Ramping in will not be an issue though. As long as the ramp isn't too vertical, it should be fine. As for pocketing, I wouldn't choose that tool. There are other factors that you didn't include, like depth of cut, material to be cut, inside corners needing smaller radii than a flycutter will give, whether finish is important, etc. I use my flycutter for what it was designed for, and occasionally planing boards for thickness. Remember there is a limit on depth of cut for most flycutter designs that shouldn't be exceeded.

From contributor M:
You can pocket with a fly cutter, but it is rarely the best tool for the job. It also depends on the diameter of the fly cutter, these come in 2” thru 4" diameters. I have to use a two degree ramp on my 4 inch cutter to pocket with it, and then have to deal with clearing a 2" radiused corner with a separate tool. I am also pretty limited in depth to 12mm absolute max, but don’t try to take a 12mm pass in white oak 4” wide!

I do use it occasionally to pocket out areas of pre-laminated material to expose the core, (say you are making a microwave cabinet with a white melamine interior and want to change the color of the laminate where the microwave sits for example), but that would be the rare large area of thin material. I do most large pockets with a 50mm stagger tooth replaceable tip hogging bit.

From contributor B:
Don't forget too that you needed use only one bit for pocketing. If you are cutting a lot of pockets or large pockets, you can mill out the majority with a larger diameter bit and cut the perimeter with a smaller diameter, reducing the rounded corners. Most modern programs can actually do this as a step rather than having to program it separately.