Standing and sitting

 I've been standing at my desk instead of sitting.  It has really helped my back.  Enough that I can concentrate on work.  Now my legs and feet ache.  I'm able to move the keyboard/mouse and sit, but the monitors are too far away.  I've ordered a new chair that I know will work so I should be ok sitting. However, I still think standing is good too.

You can see in the previous post, I have a laptop & 2 monitors.  I could adjust the stand I made, but not with everything on it.  It's time for a stand that can adjust with everything on it.  And to make it wider (13") so nothing hangs off the ledge.

I've seen some DIY lifts that use an X with 1 side fixed and the other moving.  Unless all the weight is on one side, it won't work for something distributed across the whole thing.  I decided to go with a scissor jack, like for a car.  The base is fixed, the top is fixed and a screw adjusts it. 

By using 2 crosses, I can have a wide stance to support across the whole 56".  The middle pivots are 12.5" apart.  And front to back are about the same.

I want to raise & lower about 20".  To make the crosses, I cut 8 pieces of wood to 22".  So, we have 8 links.

I found the center, drilled a hole and then drilled another hole just a bit in from the end (1/2"?).

I used those holes to drill another piece with matching holes.  Then, with a bolt in the center, I rotated the bottom piece to its undrilled end & drilled through.  Using this, the distance from center to the either end will match.  And then I drilled all the rest to match.

For the base, I have a long piece of 1x3.  I purchased v grooved wheels with bearings to roll along it.  It's important the the bolts through the wheels are the same height as the fixed bolts. 

I'm using 1/4" 20tpi bolts everywhere.  I have washers between pieces of wood to reduce friction.  The wheel bearing is recessed so I stack 2 washers and the fender washer prevents the wheel from rubbing wood.

I have a strip of 1/4" oak nailed to the base that works as a rail for the V.  Just lightly planed square off the bandsaw.

 

The crossed links are separated by a small block of wood and washers.  The total thickness should be the same as the 1x3 used for the base & top.

Looking at the end with the top & base.  You can see the oak strip is offset.

 Here is my initial assembly.  I have 3 horizontals fixed with dowels to the 2 56" long base pieces.  The front top rail is screwed to the desktop left right & center.  The back top rail is only screwed in the center.

With everything tightened down, it moves smoothly up & down.  If you look at the cross bolts, you can see the crossbars I bolted between.  This adds strength & some stability front to back.  

I used insert nuts in the end of the crossbar.  It's bolt -> washer -> wood link -> washer -> wood spacer block -> washer -> wood link -> washer -> insert nut -> crossbar.  The cross bars are oak.  Because I have lots of it.  And this is the part to raise & lower the desk stand.

I drilled holes in the center of the crossbars.  In one crossbar, I put a threaded insert.  

I screwed a piece of 1/4"-20 rod through the insert and through the hole in the other crossbar.  On the end of the rod on the other side of the hole I put 2 fender washers with paste wax between and then 2 nuts that I jammed together.  I also put paste wax on the threaded rod to help lubricate it.

There is lots of tension in the mechanism.  Enough to bow the 1x3s upward 1/4" in the middle when fully raised.  When moving, there can be a shift front to back that is easy to steady with a hand.

In the raised position, you can see the drill I'm using to move it.  It stays in that position, not moving left or right.  It's quick and I can't imagine how long it would take otherwise.

I'm pleased with this.  When seated or standing, everything is at the right height.  

 I'll have to add something to hold the keyboard & track when standing.   Perhaps something I can remove when sitting.

I might eventually wear the holes the bolts go through, but I can make the holes bigger and put some kind of bushing in if it matters.  They're only pine.

The 1/4-20 rod might not hold up.  I think the paste wax lubricating it will keep it from overheating.  The tension might fatigue it.  I'm going to put a rope around the crossbars as a safety when it's raised.  That will give be time to look for a thicker rod with coarser threads that will move quicker.