Saturday, August 24, 2013

Matt's Adjustable desk - finished!

The completed desk, at standing height. (Please ignore the other white desk below it)
Hi all! It's been a while since I last posted, but I haven't been idle. Anyway, low volume is one of the main benefits to subscribing to this blog. I'll be posting some of the things I've been working on lately in the near future. Let's start with this very odd adjustable desk that I built with and for my friend Matt (also Aaron helped).

Matt's design requirements were simple, but ambitious. The goal was to make an adjustable computer desk that could easily be adjusted for use at a wide range of heights, from standing to sitting cross-legged on the floor. It also had to be easy to disassemble and move. The basic idea was to have all table surfaces, keyboard trays, monitor mounts, and computers move vertically together, with computers and wires hidden from sight on the back. Matt and I discussed many design ideas, including some with pulleys and springs, but ultimately landed on this more simple and solid design that requires a few minutes of aerobic excercise and a wrench to adjust.

Rather than write a whole lot more, here's a bunch of pictures to show you some of what we went through:
I look over our Ash that we had cut to size.
Aaron and Matt with the frame that will form the basis of the monitor mounting area. Made with table-saw dadoes/rebates, glue, and screws. The vertical pieces extent down so they can bolt on to the tabletop portion.
This single bolt attaches a tabletop support to one vertical side of the monitor-mounting frame. We have checked it for square one last time and clamped it in place before drilling the other holes.

There are two tees now. The nuts are inset flush into the wood and epoxied in place. Bolts are trimmed to match. All this so they don't interfere with our adjustment system.
This is the mounting hardware for the trestle legs, (which you haven't seen yet). The horizontal parts on the floor are at least 5' long and the verticals are more like 6'. Three large bolts connect two overlapping boards. You'll get a better look at this later.
Getting ready for the adjustment system, which requires extremely accurate measurements. Step 1 was to make sure we don't use this inaccurate yardstick by accident.
We drilled holes every 3.5" inches. For accurate positioning, we are using this hastily improvised guide fence and a bolt to index on the previous hole.
These holes will be used with another set of holes on the trestle legs that are spaced every 3". Using the same principles as a vernier calliper, we can adjust the desk height in 0.5" increments even though the holes are more widely spaced.
A second row of holes to match the first. We planned this so that the monitor-mounting box will have four bolts attaching it to the trestle legs. They will stay in the vicinity of each of the four corners, no matter the height. This took a lot of time poring over graph paper to get right.
Jumping ahead a bit. A strip of ash gets dowelled and glued onto the front of the main work surface.
While the glue dries, we prepare to dowel it onto its supports.
Dowelling the back work surface on to supports, which will hold a computer and any other necessary objects with less visual appeal than whatever is on the monitors.
From the back, you can see the handy little storage area inside the monitor-mounting box. We have set some blue tape and other handy items in there while working. The vertical plywood is where the monitors will be mounted.
The front/main work surface has some finish on it and is starting to look the part.
Here is a dicey repair in progress. We accidentally sanded through the plywood's veneer right near a dowel. We then alvaged more veneer off a scrap of the same plywood, then glued and sanded it until the dowel wasn't covered. When this photo was taken, there was still a little more sanding to do. Next time it might be better to be more careful in the first place.
These adjustable metal arms will hold monitors. The nearby holes are for cables.
Here the desk is in place, but missing the work-surface sub-assembly.
From the side, you can see how the vernier-adjusters work. This is a good standing height. Note the white desk at a more typical height for comparison.
The desk surface gets bolted on from the inside out. A computer and 2 monitors have been added. A 4' power strip is even nestled in there right between the back work surface and the vertical parts.
Here it is, ready to do its job. The white desk in the picture just got replaced.