Joist Splines...

For the spline's, 7/16" Oriented Strand Board (OSB-Waferboard), was cut to approximately 4" in width. Before making the individual cuts, the sheet was cut down to the final length to save cutting each individual spline afterward. The width of the spline is determined by the depth of the dado cut into the rail's. I always cut the rails first and then use a scrap piece of OSB cut just slightly wider than I think I need. This allows me to slowly remove material from the width until it is exactly what I want (clamp everything tight to simulate the finished width of the product). After I have achieved the right specs., I move onto cutting/ripping the actual splines.

I have learned to never experiment on what would be the finished product. Take the time to do the set-up, measure everything twice and err on the side of having too much than too little. You can always remove material, but never put it back after a bad cut.