On old TS trick for angled holes in a wood grille
1. Make an angled fence for your TS miter gauge & make it long enough
to support the wood blank all the way across from corner to corner
2. Set up your dado to whetever width you want the openings & raise it
to just over half the thickness of your wood ( maybe 1/32")
3. Lay & clamp the wood strips between the fence & your blade
4. Mark your fence with the number of passes it will take to cut dados
all the way across your board from corner to corner
5. Cut dados on one side
6. flip the board & cut dados on the other side. (also rotate it 90
degrees)
You should have your grille. It will take some experimenting to get
the angle of the holes you want. If you don't mind square holes, you
could just use the fence & cut one side, flip, & turn 90 degrees, cut
the other side, move the fence & etc. Let me know how it works for you