Wood shrinkage issue

[Kevin Jenness]

Are the drawer sides and/or cabinet dividers flatsawn? The issue may be those parts cupping rather than (unlikely imo) the overall opening size shrinking. In any case the primary cause is the difference between shop and in-service conditions. You could conceivably air-condition your shop in summer to minimize that but the truth is in climates like mine there is going to be a significant seasonal swing in relative humidity in use and it has to be designed for. That may mean easing off on the desired piston fit of drawers, using different species or cuts of wood for drawers and related parts or designing your drawers differently. As Mel said you can make NK style drawers with slips for the groove that are wider than the body of the drawer sides (or drawer sides milled thicker at the base) so that a relatively tight fit can be made only at the slips. https://www.finewoodworking.com/forum/nk-drawers