Plywood

Notes and properties

End/Edge-Grain

The convenience and power of plywood material is immediately compromised by problems and quirks resulting from plywood edge-grain. The cut edges of ply are far from the Euclidean ideal we'd prefer. Voids (both small and large), tear out, and gaps due to delamination cause plywood edges perform quite poorly as a surface.

Deeper Plywood Edge/End Grain Notes in their own page.

Thicknesses

Manuf / Type Nominal Th. Average Th. Max Th. Measured Notes
Plytanium 1/4 0.292 0.292 0.292 0.292 Not sure how this is thicker than 1/4", maybe I purchased something different?
Plytanium 1/2 0.476 0.486 .486 .463 .484 .473
Hardwood Birch 1/2 0.473 0.473 .473 .473

Fit

This table has data I've discovered empirically for the fit between mating pieces of ply. This is a shorthand method that assumes that the mating surfaces are ply-thickness on the one hand and a CNC-cut slot or span on the other. Fit spacing is total span of gap added to negative from positive. For example, if a tenon is 1.00" and the span gap was 0.01", then the mortise slot would be 1.01" wide. When poor plywood is used, this is a distance from max possible thickness. See Appendix A for more notes and details.

Manuf / Type Tab-Slot Spacing Notes
Plytanium 0.01 TESTING
Generic Quality Hardwood 0.01 TESTING

Appendix A: Notes on Experimental Data

To add: when I finish first round of fit tests