Simple Desk Design. Tenon Array Joint.

My local Menards store had 1.5" thick butcher block birch counter/bench tops on sale recently.  I needed a new desk to replace a plastic topped desk that I use as a computer desk.  The plastic top rests on a metal tube base, but has started to sag and crack under the weight and heat from my PC.

I previously came up with a tenon array joint that makes a great connection between legs ends and table tops. The 1.5" thick hardwood is plenty thick for a good joint. All I would need would be something with a little cross sectional area to use for legs to support it. No stretchers required.

I've used cedar 4x4 posts in the past as legs for shop benches and my CNC cart.  With a little picking through of what was available I found some straight and clear 8' cedar 4x4s to use.

I wanted my desk to be 29" to the top when done.   I cut 4 leg sections roughly 28.5" long to allow for 1 inch tenons to penetrate the top.

   My CNC just barely had the capacity to hold the 48" x 25" top.  I used it as shown to cut the four mortise arrays each centered 1/5 of the length and width from the edges of the top.

The legs were first cut at a compound angle to tilt 4 degrees in the long direction and 2 degrees in the short direction.  Then I clamped them into my compound angle clamping rig and cut the tenon arrays with the CNC.  I made the tenons .004" smaller than the mortises for a slip fit and some room for glue.

I left the top clamped to the CNC while I tested the fit of the joints. I made a mistake when cutting the end on one of the legs, so I had to recut it a little shorter.   The tenons ended up .75" long and the mortises I cut .8" deep.  The legs slipped in with just a little wiggling back and forth. They come out using the same technique.

 If the legs would not have fit easily I could revise the CNC file for the mortises and recut them a little larger.   I didn't need to in this case.  All legs fit fine.

I haven't glued the legs in yet.  They need some sanding and finish, which will be easier with them detached from the top.  The outward flare of the legs give the desk a more solid stance, with less tendency to rack or twist than if they were vertical and all parallel.

The 3.5" x 3.5" mass of the legs has room for and begs a more interesting profile.   In use though I'll never see these legs. The birch top will look great with some clear finish on it.   I may paint the legs white or black to make a less distracting setting for the top.

I used my CNC to chamfer the bottom of the legs. With the bottom plane at a compound angle each corner bevel is slightly different.  A little hard to see in the photo below as most of the 1/2" chamfer sinks into the carpet.  The chamfer should keep the leg bottoms from getting snagged/worn as the table is moved/scooted around.

4D