Anyone done this? This is a groove inside a bore that runs parallel to the axis (linear) vs. alond the radius like threads.
The store's keyway broach sets are pricey:
http://www.grizzly.com/catalog/2004/483.cfm?
I'm thinking about using a dremel 90-degree cutter head, and mount this along a piece of PVC pipe that is fitted to the ID of the bore, and use a simple routing bit to cut into the material. The PVC would be the "jig" to ensure the router bit stays in the correct location, then just run it up/down the bore of the tube.
If this doesn't work, I'm thinking about cutting a slit down the bore, then putting a shim of some sort down it that will mimic a keyway.
Any other ideas? I don't want to spend a great deal of time building a tool...