Hammo Can - Radiated Nerdism

I'm a HAM.  Not that I'm funny, seriously, I'm a HAM.  An amateur radio operator.  I function as an emergency contact for neighborhood issues when infrastructure is down, as well as a point of contact and support for the city (I work with both data networks as well as voice networks in the radio environment).  I also work for a local healthcare company on their radio connection network in my spare time.  It's not what I do for a career, this is what I do for kicks and giggles.  My current portable radios are poor, my wife doesn't want an awful antenna sticking up from the house, and that leaves either a permanently mounted in the vehicle (it's been broken into once or twice, so things are not left in there) or a portable base station with some power.

Old ammunition storage boxes are often referred to as "ammo cans", so taking it into the world of radio and adding an "h" on the front is not a long stretch.  I am NOT the coiner of the phrase "hammo can".  I refuse to take credit on coining the terminology because, frankly, I'm not that smart.

Under the circumstances outlined above, a "hammo can" is the perfect option.  It will be light weight, portable, and not tied to a vehicle or property.  I can easily set one up under a canopy in the yard if it's needed. So, I finally decided (11 years after first obtaining my radio license) to venture into the "hammo can" world.  So, that proverbial bullet was bitten, and I started ordering parts :

• The radio is a TYT's "TH9800D".  It's tried and true, and a lot of HAM operators swear by it.  Theoretically, it will fit a Yaesu FT-8900, but I cannot confirm that without a radio.  This one also requires three m4-0.7 flat head machine screws, one being 16mm long and the other two being 12mm long.
• The container is a 50 caliber ammo can off of Amazon.  I ordered it in purple (they have other colors, and this one visually separated itself from my grab-and-go case of hard drives).
• The battery is a 12v LiFePo battery to be able to run this station for an extended period of time.
• A power manager (AtemPower AP100BM) is used in this build (and some switches so I can completely disconnect the battery for storage).
• Battery terminals (2 negative [black], one positive [red])
• Random switches and battery connectors for easier charging.
• Heat-set inserts for m3 screws - while it started out with some m2 screws threading directly into the plastic, it was eventually changed to all-m3 (except for the radio itself) for consistency.
• 27 m3x10mm machine screws (add four if you print this with the two-part top plate).
• 2 m3x10mm pan head screws (for the radio face-plate-to-battery box).
• Heat shrink tubing
• 1/4"-hole circular connectors
• 1/4" female spade connectors for the battery 
• A PL-259 90-degree elbow
• 4" Cable with PL-259 ends (male and female)
• Mounting connector for a PL-259 for the top plate 
• Wiring (I used a radio adapter that had long cables, and I just used the extra cable for all my power needs)

So, I have the hardware to have a "hammo can", but it is kinda ugly piled into a chaotic mess, and I don't want to re-organize everything before I can use it in an emergency.  I need this thing to be ready to run with only setting up an antenna.  The simpler it is in an emergency, the better.

Design 

That lead me on a course to print an insert for the "hammo can".  I mapped out a lattice, and started gluing things together in FreeCAD.  Please note - by the end of this write-up, the structure will change.  There is no lattice for rigidity, and it is all handled completely by brackets.  This will give more parts to print, but reduce the over all time it takes to print it.  But, let's skip this digression and just move to the original design.

There are compartments to slide the battery into, the radio into (faceplate goes on top), and the power management adapter.  So, I also loaded the "thing" to thingiverse if anyone else wants to go down this course of action.

I think this will work sufficiently, but it looks like it's just about 2 weeks to print (17 days).  Plus, without a brim, it looks like it just barely fits on a Creality CR-10s build plate (with a brim, it did not fit).  I do want to make one change - I'd like to make the radio area a bit more "modular" so you could potentially use other radios, so this could become a more viable option to build one-off hammo cans.  We'll see if I do.

I got into gear by printing the power module bezel (I was using it as the test platform for interrupted filament prints because the chassis is going to be 2.5 reels of filament (yes, that much).  I don't want to be so attentive for two weeks while this prints, so an empty filament reel should result in a pause.  That's two prints that I can use to make sure it is all running properly.  The power bezel print did abort, while I figured out the issues with the filament sensor housing, and I printed a new housing and had it working okay, so I could run some more tests.

I managed to get the bezel printed with interrupted prints, so I think I can test this once I get the time to do it (mid-to-late August at this point).

The bezel plate came out great.

The bezel plate will just screw in to the chassis.  There is one section I'm going to have to modify for a power shunt, so I might as well get the radio caddy a little more modular, too.  I spent a few hours getting things set up for a modular setup.

I then built out the shunt plane, as well as a modular radio, and also printed out the switch plane while I was at it.

The switch panel looks good.

There are two "generics" in the thingiverse file - one radio module and one shunt plane.  But I also have the shunt plane for the AtemPower monitor and the TH-9800D radio loaded in there.  The "generics" are in case you want to try something a wee bit different (e.g. fit in a different radio, for example).

I then started to print the shunt plane for the AtemPower (not the generic one - I don't need one of those).  Of course, the shunt plane print failed four times.  I re-leveled the bed, changed the nozzle, and then finally gave up and ordered a new PEI printing bed plate (I ordered a few, just because this could use up more  consumables like the print bed).  Then I started printing it yet again.  I'm getting close to running out of filament on one spool, so this is perfect - it's going to give me a real test of the filament sensor break.

The print was good - it finished right on time.  The shunt plane finally finished, and did not warp.  Now, if this should look funny, it's because I wanted to finish using up my silver filament.  I knew during one of these parts I would have an opportunity to prove out the filament sensor interruption, and it came about 2/3's of the second to last layer.  So, the base is "black", but the last layer is "silver".  It's going to be buried in the can, so I'm not at all worried about a discrepancy.  This print took about 4.5 hours with the filament reload.

Now for the radio module.  Since I had the silver installed, I simply just went for that.  It will all be hidden on the back end, so I'm not terribly worried about presentation here.

Again, I created a "generic" in the thingiverse file for this, but also a specific TH-9800D variation for my implementation.  If someone wants me to do a non-generic module for a different radio (if they fit in the same basic size), they can always donate a radio and I'll try to design it to make it happen.  Again, in theory, this may fit a Yaesu FT-8900 or 8800 radio (since that is what the TYT TH-9800 is based on), but no guarantees.  Send me one, and I'll make sure it does work.  I probably won't send the radio back when I'm done.

I only printed the TH-9800D radio bracket, not the generic, so I cannot vouch for the generic one's functionality, but the specific one came out well.  I assume the generic one is fine, since the TYT-specific one was based on it.  This print took about 16 hours.

I realized that my measurements were 0.039" off on the screw spacing, so I adjusted the module, but rather than take 16 hours to reprint, I just modified it using a drill.  The radio body fits in using one m4-0.7-16mm screw on the top and two m4-0.7-12mm screws on the bottom.

 

Next came the print that would take a few weeks, the one I've been testing the filament change in anticipation of - the actual chassis.  Seeing that my previous prints have come out slightly undersized, I did a quick google search, only to find out that an STL doesn't have real dimensions in it, so your slicer can only guess so much.  This means that you have to adjust the size in your slicer before you slice it.  That leads me to the following.  The chassis itself is 6.102" (154.9908mm) wide, 11.217" (284.9118mm) long, and 6.315" (160.4010mm) tall.  Okay, on to the printing.  My slicer seemed to have it pegged on dimensions well, so, off to the printer.  I know I should adjust for shrinkage, but meh.  We'll see.

This should start out in silver filament (because, again, that's what is on there), but should switch to black before the top layers when the silver filament runs out (it takes 2.5 rolls of filament, so it will definitely run out) - and that means it should look just fine on the outside.  My CDO (OCD in the right order?) will know the bottom is silver, but it will still function.

Yeah, that's a few layers of silver below the black.  Sure, it's going to look whacky, but I don't care.  (The fact that I am yet again referencing this "issue" probably means a second print later.)

This is going to take a while.  The slicer said 13.4 days, but the print isn't coming across at the same rate.  After 33 hours of printing time (started on the 11th at 8:54 AM), I've calculated each percentage point as taking 249 minutes, or 4.15 hours.  The stats claim that it will take a grand total of 17.3 days (on the dot, which puts it at finishing on the 28th at 2:54 PM) - which is what 415 hours equates to.

At the 20% mark (8:10 AM this morning on the 14th, 72 hours and 9 minutes in, I revisited the stats.  The target date shifted from the 28th at 2:54 PM to the 26th at 8:46 AM.  The per-percentage time went from 249 up to 277, which makes me question my math in one of these two check points.  We'll see what happens.  It does look good, and taking random photographs will help me post-process the supports, clearing this up.  As I work through it, the photos will definitely come in handy.

The next check point, 7:37 AM on the 15th, was 27% complete, with about 1.888" of height, 94 hours and 36 minutes into this (5,676 total minutes so far).  On this one, I took the time to also measure the chain guard distance to the stabilizer, because I know the stabilizing rods get in the way of the x chain.  That came out as 6.146" of height remaining, and the calculations are to 5.664" of height left (which falls a lot longer than the 6.315" of total height).

This 21,022.2222 minutes in total, or 14 days, 14 hours, and 22 minutes.  That brings the new estimate of completion to the 25th at 11:16 PM.  Of course, there are some filament changes that will have to happen in there somehow.

My next check point came in a few times on the 18th, while I started paying closer attention to the filament running out for a second time.  I clocked it at 171 hours and 51 minutes at 12:51 PM, and had the filament changed at 172 hours and 15 minutes at 1:39 PM, approximately 24 minutes in print time, but 48 minutes apart.  That means that the print timer itself is total time, and does not include time between filament being out to the change time - or print pauses.  That's good to know.

So, the estimate for the next filament change is the 24th at 8:46 AM.  At that point, we should be about 97% to 98% done with this, and we'd only have 1 day and 7 hours, and 53 minutes remaining (25th at 4:39 PM is the new completion target, depending on how much time I waste forgetting I need to change the filament).

It is now 62% done, but at 59% done, it was 203 hours and 45 minutes into the print, and 4.374" tall.   If this was fully linear, it would mean that the print would be 7.414" tall, but we know that the print should only be 6.315", so we have nearly a full inch shorter.  This is a solid indicator that the print percentage is NOT in layer count, it is either in over-all time, or in total distance of filament printed.  At this rate, it should be 5 days, 21 hours, and 35 minutes remaining, a target completion of the 25th at around 9:50 PM.

Now, if only I could wait patiently (and hope we don't have a power outage in the next 5 days, 13 hours, 22 minutes, and 46 seconds).

Bugger.

9 days in, at 66.3% complete, I walk into the room (I'm not living in the same room as this thing for a week) and hear odd noises.

The nozzle is being scraped across the top of the print!

Apparently, I printed a 6.35"x6.1"x4.6" pile of a roll of filament.  I aborted the print job, and grudgingly went back to the drawing board.  [sigh].

No fancy lattice work, no huge set of prints, and all of the modular parts will still fit.  This also includes other improvements that were re-developed int6o the new structure (I thought I would see interference on the corners with the curves in the can itself, so I added some fillets to work around that).  So, off to print a few parts for the printer itself, then to start with the four new parts :

• The bracket that ties the shunt plane to the radio, the battery, and to the top plate
• The extra corner bracket (where I have some space that could be used in the future if I wanted to add networking components or Raspberry Pi's)
• The new top plate with mounting tabs
• Battery box 

All said and done, these four new parts should take approximately 5 days to print - a massive difference in time down from the 15 days it was going to take.  Additionally, these new brackets can also be adjusted to make this even more customizable.  The top did not fit with a raft - so I created a 2-part top plate.  However, I really don't like the visual, but it does still function, so if you are making one of these without a large printer, it will still work.

The top parts did get plastic-welded together after being bolted with screws.  Here it is without the plastic-weld, which is still functional.

And the visual... really isn't so bad!  The top panel pieces took 40 hours and 40 minutes on the CR-10s with 100% infill and a raft, which is why the surface is a bit sub-par.  Here it is with the top panels all combined, and with no wiring.

Next was the battery box. Started at 9:44 Aug 31, followed by the brackets.  And, after all that, it finally started to come together!

Assembly

1. Install the heat-set inserts in ALL the parts.  If you used the two-part top plate, you will use an extra four of the inserts, and an extra four of the m3x10mm machine screws.
2. Next, install the radio itself to the radio module.
3. If you printed the two-part top plate, combine the two top plates together with four screws.  Plastic-weld the two parts together (*this is purely optional*).
4. Fit the switch plate to the top plate, and screw together.
5. Install wiring on the radio body side of the switch (you won't be able to get to that after you install the radio). 
6. Temporarily install the radio face plate (the part that comes with your radio) to the adapter block, but do not tighten.
7. Install the radio face plate to the top plate.
8. Measure where the radio adapter bracket (what came with your radio, not the block itself) sits, and remove the block and radio face plate.
9. Re-install the radio adapter bracket without the radio face plate itself to the adapter block.
10. Install the radio face plate adapter block and bracket to the top chassis plate again.
11. Shift the radio face plate adapter until it matches what was measured above in step 7.
12. Tighten the radio face plate adapter bracket (what came with the radio) to the adapter block.
13. Remove the adapter block, and add the cables required for the radio face plate, and install the face plate to the adapter block/bracket combination.
14. Install the battery box to the top plate through the radio face plate connector.
15. Install the radio face plate to the top chassis, running cables into the cavity underneath the box where they can be connected to the radio. 
16. Fit the power module into the bezel, then attach it to the top plate.
17. Install the battery connectors for the top plate.
18. Install the radio module itself to the top chassis.
19. Install wiring to the battery, and to the power module, the remaining switch terminals, the battery terminals, the battery box (add the connectors for the battery, too) and the radio itself.  In my case, the negative battery was wired to the switch, then to one battery terminal.  I essentially used the battery posts on the top chassis plate for the interconnection of wires.
20. Install the extra bracket.
21. Install the shunt plane bracket (not the adapter). 
22. Insert the battery to the battery box, and strap it in using a velcro strap (not really required, but recommended to prevent the battery from bouncing around) to secure it in position.
23. Route wires around the shunt plane bracket.
24. Install the radio module shunt plane adapter and shunt plane.
25. Program the radio using your computer (again, while optional, I highly recommend it).
26. Drop the block into the hammo can.
27. Weather strip around the top edge to lock the panel into position and secure the chassis. 

I did use a strap to hold the battery when I started putting it together.  It rattled around and went flying through the air and landed on toes when pulling the chassis in and out of the can while assemling.

 

I finally got the last few parts to finish putting this together (the one remaining battery terminal, and the antenna connector).

It does fire up, and things appear to be operational!

Your radio should now be ready for an antenna and an emergency.  A good source of information is the "Radio Reference" database (https://www.radioreference.com/db/aid/7771) where you can look up frequencies specific to your location.  I would recommend (if your radio supports these frequencies) :

• 27.065 (CB Channel 9) - Emergency
• 52.525 (6-meter) - FM emergency band for ham radio operators
• 138.225 - FEMA disaster relief (primary)
• 146.52 (2-meter) - non-repeater, HAM frequency
• Local Fire, Police, and Search and Rescue (frequencies will vary by location)
• 156.75 - maritime weather alerts
• 156.80 - maritime distress
• 163.4875 - national guard emergency channel
• 163.5125 - armed forces disaster preparedness
• 168.55 - federal civilian agency for emergencies and disasters
• 243.00 - military aviation emergency
• 462.675 (70cm) - GMRS emergency channel 20

Once set up, connect your antenna and give it a test run.

Summary 

Now, while I don't like the finish of the top surface, nor the fit, I think this will be operational for what I need, and I secretly think this is awesome.  I'm hoping to surround the top plate with weather stripping, and put some custom gaskets beneath the switch and power bezels for a bit more moisture-sealing, but with the gaps under the radio faceplate itself, this is definitely NOT water tight.  I'd like to revisit an antenna (if I can find a purple pipe wide enough to protect the antenna as well as act as a bit of a stand) to see if I can get that a bit more appealing.

With all of these prints together, it was time to assemble the whole thing.

And with that, we have a "hammo can" (portable base station) for emergency use! 

Old Hard Drives

When you visit family, and someone hands you an old hard drive from 22 years ago and asks for a data recovery because it could have your moms letters on it, you don't question it.  Grab that hard drive and take it.

So I started a little journey.  I popped it into my PATA USB case, and plugged it in.  It did not register with the system (I'm using Linux so I should at least see a USB interface get logged, even if the hardware has failed).

It spun up.  There were no clicks (so the hardware had not failed).  I dug into the logs - nothing, indicating the interface board was likely the problem.

So, I took the interface board off.  It was a Western Digital WD400 from 2003 (I told you it was 22 years old).  I grabbed my Western Digital WD400 from my case and started to swap the interface boards temporarily to commence a recovery.

One screw changed between them.  There are associated with the WD400 product line, but actually have different model numbers.  I'd wager that if it wasn't for that screw being in the wrong place and not being able to be anchored down properly, it would have been perfect, yet this would not be.

I could have 3D printed a bracket that fit across and held the interface circuit board down, but I just put the original back in, and looked at the jumpers.  Old PATA/IDE hard drives had a jumper on them for "Master", "Slave", and sometimes one or two other options (such as "CS" or "Chip Select").  There were no more than two IDE drives on the same IDE cable because of the electronic design.  One would be designated the "master", and the other a "slave".  In later years, they added a "chip select" option to try and make it a little more plug-and-play.

I had the thought I should move the jumper from Master to CS, and suddenly the old interface loaded when it was reconnected.  Ah hah!

It loaded no files (an empty filesystem).  The next step is always to run a recovery, just in case a new filesystem was put over the top of an old one.  So, I ran :

photorec /d Documents/recovery /dev/sdc

This dumped a few web files (CSS, XML, and HTML), a few executables (EXE and DLL), a few TXT files (that turned out to be nothing more than configuration files, registry files and some text extracted from executables).  Two files, a WAB and an EDB, both stood out to me, because a WAB is supposedly a Web Address Book, and EDB is an Exchange Database.  Turns out, they were simply mislabeled data files for the executables.

 No, the drives did not have any letters from my mother.  But it's better to know than not to. 

Doh! A Delicious Dish of Dumb Dumb!

Alright.  I'm only posting this because of the blatant error in my own reverse engineering.  I had a Coleman pop-up canopy, with fancy "push button" locks and unlocks.  It's really not bad - it's survived for 10 years with only minimal issues.  (Two years ago, one of the locking mechanisms on one leg wouldn't release.)  Here it is in all it's glory (still in it's bag).
 

This year, that same locking mechanism released (perhaps a better term is it fell apart).  Since I had silver filament and these were gray, I thought, what could I lose?  I'll see if I can draft and model up a replacement part, and print it.

I started out by taking the few remaining parts off to see what was broken.  This is a pretty ingenious device.  I'm impressed with the design (but not so much the implementation).

The broken part is circled in red above.  A few more photos, just to make sure :

It is time to create the model.  I whipped this up in FreeCAD :

About 50% done (I'm doing 100% in fill so it is solid), I picked up one of the parts, and realized - I didn't look deep enough.  There are two locking tabs on each end (I got both of those), and... recesses in the mating part where there were supposed to be four more locking tabs on the sides.

Really?  I play the part of an idiot VERY well, sometimes.  I'm missing the ones in green here.  Notice, I had them listed as an alignment pin.  Looking closer to the original, and these locking tabs had broken off (three of the four were down to the plate, one was half height, and I built all four off of that one).

So, back to the drawing board. I simply copied one of the two tabs and positioned the four new instances.

Okay, we can try printing this once more. Here we go.  8 hours and 38 minutes.

Alright.  The overall length should be 2.904", but the final print came out at 2.890.  In Cura, it shows 73.6, which is about 2.898", so we're losing about 0.008" in the print, and Cura is also not getting sizes from the STL file with much accuracy from FreeCAD.  That should be just fine, really, as long as I remember to adjust the size by 100.48% before slicing.

It looks good, the clean up was good (the aborted print gave me an idea of how this was going to be cleaned up), and with some fine adjustments (hobby knife and a Dremel for some inside work), it works exactly as I'd hoped.

I went to install it, and it simply didn't lock together.  So, that led me on a re-do, and I added the toggle cover with a new base that screwed together (no tabs).  This particular variation uses screws to bring the cover and the main housing together, but uses the same toggle switch itself, the same spring, and the same spring assembly.

Note, be careful how you print this - if you print side-to-side instead of top-to-bottom, the locking tab that holds the housing to the actual metal upper leg will break, and then you have to superglue it into place (ask me how I know). 

I have my canopy back! 

Moving Badge Access to your Finger

I work for an entity that implements physical security for pretty much everything.  Workstations in the office can even have their own badge reader (through "Imprivata") to "login".  One group of employees we cater to absolutely uses these systems to keep notes, and to be able to move from one office to another quickly and effectively.  The badge access systems make "authentication" quicker and slicker.

I wanted to make it even easier than reaching for my badge to tap in and out of the computer, so I bought a T5577 RFID writable ring off of Amazon, and an RFID reader/writer.  At first, I got fairly frustrated that neither of those tools did what they were supposed to do.

Then I made one adjustment, and things were suddenly magic.

So, what did I do?

Use the mode key to select "HID 125KHz".

Once the HID 125KHz is selected, insert the badge, and press "read".

The device will then say to put the T5577 card in and press "Write".  This will take some trial and error to find the right position to hold the ring for writing.

Once you have a successful position and press write, it will tell you it was successful.

With that, it was time to test it.  At a workstation, I used my primary badge, and locked the session.  Then I tried with my hand (ring) to unlock, and the light indicator went to "green" from "red", showing success.

The workstation unlocked, angels sang from the skies above, and I was suddenly being served pina coladas on a beach in Tahiti.  (Well, one of the three was true.) 

Now, it did NOT work at the office doors - those apparently require encryption on the badges that this simply cannot do.  I'll have to think around that.

Folding Desk

There have been a few times where I've had to temporarily set up "shop" (my workstation) in different places around the house.  For example, when we have a visitor and the bedroom immediately next to the workstation is occupied and the time they wake up doesn't match.

These situations have usually had me splitting the expanding table and attaching a dual monitor stand in between the two haves, then pushing back together and setting up in the kitchen.

I have a folding drafting table, and I wanted something similar I could use for a workstation.  I was severely tempted to just purchase a butcher block top along with a folding stand, but if you know me, if I'm going to put one together, I might as well go all the way.  I had some aluminum extrusion laying about for a different project that ended up not being used, so my brain said.... why not?

 I set about designing the desk in my head, and then just threw it together.  Here's what you'll need (with modifications from what I did because you likely will make changes).  Since I was doing this with 2020 series extrusion, my bolts and nuts were all M5.

• 3 fir boards 2x6 that are 10 feet long
• Biscuits
• Wood glue
  
• 2x 48" horizontal extrusion rails for the main body (mine were shorter, and you'll see overlap on the folding ends later, which messes with my CDO, er,  OCD)
• 2x 43" slanted extrusion rail to stabilize the main body (these form the "x" in the main body and stabilize the whole thing - one will need to be cut into two pieces, but do that after the first one is in place)
• 4x 23.5" horizontal extrusion rails for the folding ends
• 2x 27" slanted extrusion rails to stabilize the folding ends
  
• 6x 26" vertical extrusion rails for the height of the desk
• 8x 45-degree brackets for the extrusion rail
• 8x 135-degree brackets for the extrusion rail
• 16x corner hardware brackets
• 76 bolts (I had 40 for the piano hinges, so your mileage may vary depending on your hinges)
• 76 washers
• 76 extrusion nuts
• 2x Piano hinges about 20" long
• 12x extrusion end caps
  

Tools you'll need :

• A square
• Allen keys for the bolts
• A biscuit cutter
• A chop saw for the boards
• A band saw to cut the extrusion to length (and some angled cuts)
• Panel clamps (I used quick clamps along with off-cut boards to keep flat and Saranwrap to keep those off cuts from sticking to the glued up surface)
• Sanding pads
• Planes (optional)
  

First, cut the extrusion to the lengths you need.

Second, for the slanted pieces, cut the folding ends to 45 degree angles (angles are NOT parallel for these, but opposite of each other).  The main body angles ARE parallel.

Third, start bolting each frame it all (except for the second cross bar in the main body) together.

Once it is all together, you can mark where to cut the second cross bar in the back, cut it, and install that one half.  Then you can line up the other half and mark where that one needs to be cut as well, cut it, and then install it.

With that done, you can then mark where the top bar of the main body connects to the cross bars.  Then, remove the top bar on the main body, and cut those two pieces off, then reinstall the two pieces.  This should keep the whole thing somewhat stable.  That middle section shouldn't be discarded yet - in fact, you will cut a little more off and re-install it about 6" below where it originally was.  This should give you clearance.  (Pictures don't show it offset until you get to the end of this post, and they don't show the second cross bar installed, so be aware).

Fourth, install the hinges (but don't tighten quite yet).  With the folding area in place, open one end perpendicular to the main body and get it square and vertical to the floor.  While in that position, tighten the open ends' hinges to secure it in place.  Repeat for the other folding end.

You should now have a folding rack and desk base.

Yes, notice the folded ends overlapping.  This is because my desk was less than the 48" I've now recommended above.  But it's still "functional".  Anyway, back to the build.

Next, cut the fir 2x6 boards in half.  This should fit the span of the desk.  Line them up in position on the desk surface, and mark and cut for biscuits.

Then, glue it all up and wait.

With the surface glued up, it's time to finish it.  Granted, you don't have to, but you won't be using the desk to write with the way 2x6's have curved corners.  I'd recommend you use the hand planer to get it flat, and then sand and finish.  However, you may want to simply pour epoxy in (sealing the ends, of course) until you build it up far enough to have a flat surface.  My unfinished, but usable workstation :

I used lacquer spray to somewhat seal the bottom (I did not spray the top), and then taped the bottom and edges so I didn't have epoxy run all over.  While there, I also hammered some small gears, screws, etc into the surface.  All of that was filled with a metallic bronze epoxy mixture, then sanded.  I went to 220 grit top, bottom, and edges, then went 800 grit on the top and edges.  Then I lacquered the whole thing (yes, even the bottom again).  Once done, I hit it briefly with 2000 grit sand paper to knock off the little spikes that form (this spray can lacquer isn't the greatest and smoothest finish after spraying).

That gave me a phenomenal surface that won't poke holes in paper, and won't snag on clothes.  It also has a great look to it.  The epoxy will look black or dark unless the light hits it at a specific angle, so everything blends together in a fantastic way. 

I will have to build the nipples for the bottom of the table, the threaded tubes to make it a standing desk, and the fixtures for the top of the stand itself.  I whipped up the specs for machining the 12 remaining parts required (for what I'm doing at least - you COULD adjust with a top hinge and make it only a fully folding sitting desk.  I want the option of standing, so I'm manufacturing a few pieces yet.

I built a fixture plate that bolted to my lathe faceplate (so that I could screw the next part onto it and just make it match), and then did some bandsaw work so I could reduce the amount of turning work I'd have to do, and started cranking through. 

I needed four nipples for the bottom of the desktop, four threaded mounts for the frame, and four pipes with one end threaded to the same thing as the frame mount.  Plus, I had to shorten some M5 screws.

Once these were created, I could install the frame-to-table parts.

Then it to flip the desktop over, line it up, then install the nipples to the bottom.

A final test before I install the standing spacers :

And the final spacers :

I did slap the laptop on it and work in standing position for an afternoon.  This will work well for me when I need to be on the move.

 

Next, I didn't want to lose the aluminum "standing" rods, so I printed a storage case that simply connects in and locks them when not in use.

Now, I went to use this for a little bit, and there have been some issues.  When it was in "sitting" mode, the height just wasn't quite right.  So, I trimmed off lengths 3" (I already updated the measurements above).  When I tried to use a dual monitor stand that snugs onto the desktop itself, the rear, top bar was in the way.  I added a second cross bar in the main body (pic below), and I cut out the top cross bar and moved that down 6" so I could have clearance for the monitors.  When I threaded the standing-mode bars on, some wouldn't go on all the way.  I ran a threaded die onto them and cleaned up the threads (I had to use an adjustable die so that I could get it perfect, and that meant running it over the threads a few times while adjusting it tighter in between until it fit just right.

 

I'm loving this thing!  It is now perfectly level, it has excellent stability (though it is a bit heavier), and it all just works as it was designed.

 Now, if I have a mobile Internet connection, we could go just about anywhere and work, and my family can wander off to see sights while I work.  This would be good, as long as the family doesn't get eaten by bears without me.  That would be bad.   Perhaps if I'm eaten by bears along with them, but not without them.