Making through-slots without a router may sound tricky, but it couldn’t be easier. In the days before I could afford a router, I made through-slots by gluing up scraps instead.
Here’s how to do it. Cut some pieces the same width as your desired slot. Cut these slot spacers to length and then glue them between two outer boards. This method is so easy that even after I purchased a router, I never used it to make through slot.
This method is a great way to use up scraps. Also, slot widths aren’t dependent on any particular bit size. You can make them any width you need.
The photo shows one of my favorite applications for through-slotted boards; adjustable workbench legs. If your shop’s floors are uneven like mine, adjustable legs are essential. A wiggly workbench is unbelievably annoying. -John Cusimano