I received several questions about making and using drawer slips; in this entry I will show how I do it, using power tools and a simple layout technique.
Drawer slips are are grooved strips of wood, used primarily to hold the drawer bottom in place. It is a terrific way to reinforce thin drawer sides. The slips are glued to the sides, to provide the reinforcement. I showed one such slip in a sample drawer prepared for a client – nothing was yet glued:
It was this photo that prompted several questions from readers.
In the photo above, notice that the slip projects just below the drawer side. In fitting the drawer, the slips are planed even with the sides, which increases the total surface area; this results in reduced wear of the frame supporting the drawer(s).
What follows is how I go about making the slips, using simple tongue & groove joinery; rabbets would also be a good joinery choice.
I start by preparing several strips, including some spares that I will use for machine setup and testing – notice I match and mark each pair, to enhance their appearance when placed in the drawer:
Using one of the spare strips, I set up the groove router bit to height. A straight edge helps me align the bit’s bearing with the fence:
Remember the spare slips? I use one to assure myself the router bit height and groove depth are properly set:
A tip on the use of the tongue & groove router bit set I use: The “show face” is always down, to ensure flush surfaces of the assembled pieces. The router bits are perfectly matched in height, which simplifies changing from one bit to the other as needed.
Once satisfied the setup is good, I machine the grooves in all strips. Then I change to the tongue bit, in preparation to machine the tongues on the drawer panels:
Do you notice the bearing sandwiched between the cutters in the router bit above? This bearing is registered with the fence in the say as I showed for the groove bit. Another tip: The offset wrench allows me to change bits without changing the height of the bits!
Before machining the tongues on the bottom panels, I must first dimension the panels to proper width. I start by clamping two slips to one drawer edge, measuring the width, and adding 7/16″; this allows for machining the two 1/4″ tongues, while leaving 1/16″ of side-to-side movement. Then I mark a story stick with this dimension:
After trimming the bottom panels to proper width, I now machine the tongues – the Feather Guard is my third hand, as it keeps the edge of the panel tight against the router table top while I press the panel against the fence:
The next photo shows the bottom panel inserted in the slip. Notice the perfect alignment on the top edges – this is possible because I did not have to change the bit height:
All that is left at this point is to machine a very slight roundover on the top inside edge of the slip. After trimming the slips to proper length, and gluing them to the sides, the drawers will be ready for glue-up. Note to self: I must remember to machine the groove on the drawer fronts…
If you are interested in drawers, you might want to watch the video of Mario Rodriguez I shot during the Woodworking in America conference at Valley Forge, and later edited for the blog.
— Al Navas