On Sat, 01 Jan 2011 10:51:17 -0500, William Bagwell wrote:

Need shallow grooves in wood, *lots* of shallow grooves in lots of wood.
At least 48 in each side of dozens of 16 X 24" pieces of plywood and
almost as many boards grooved on only one side.
....
Have access to an old 6" jointer and think modifying the knives with a
series of flats leaving a row of cutting tips spaced approximately 1/2"
apart *might* just work. Cutting at least 12 grooves in one pass.
....
BTW these grooves need to be slightly rough. While I want to avoid
splinters extremely smooth groves are not what I need or want. Nor do I
want any radius at the top or bottom of the grooves. This would defeat
the whole purpose of having grooves for the bats little toenails to
grip

If the resulting pieces are going to be interior walls of bat
houses, it seems like you would want to simulate something like
tree bark or rough rock surfaces. Have you tried a coarse wire
brush or a flail on the plywood surface?

The surfaces of rough cut slabs probably would be ok without
further processing, if you have access to a local sawmill.

--
jiw