Custom bench for electronics lab, using T-slot extrusion frame

[TiN]

Got tired of piling equipment on top of each other, so it's time we have nice bench to make everything neat and organized. 

Since my woodworking skills are non-existent, decision was made to go with T-slotted aluminum extrusion to work as a structural frame, with plywood/MDF sheets for shelf and bench-top surfaces.

After trying multiple iterations, here's somewhat final variant.



This frame will carry all the weight and loading. About 80 meters of extrusion, ~150kg.

Estimated layout:





Many standard benches don't have enough depth to put full-size test equipment, such as calibrators, network analyzers or even just high-end oscilloscope and still leave enough area in front to work comfortably on DUTs/boards. This design supposed to solve this issue, with 1.5m deep main level working area, and additional 1.35m deep shelf for stuff like power supplies/scanners/standards/aux gear.



Here each 2 meter long section shown leveled, but actual design is flexible, and each surface can have own level to fit specific use/project.

Ideas? Suggestions?

[beanflying]

Just to throw a complete spanner in your design I would have used 3060 or even 4060 rather than the 45x45 you show. The deeper profile should tend to give less deflection on any shelves.

You might get some ideas from this recent Laser build on fittings, cutting and basic drilling and tapping for assembly of T slot. Worth a watch regardless https://www.youtube.com/channel/UCZ72zDm2feverqV7qAbNH7Q/videos

Also if you are planning on cutting your own shelves a Track Saw is a very worthwhile tool to add to your collection.

[awallin]

• any plan for how to place AC-outlets and run all the AC power cords (+possibly Ethernet switch and cords to all instruments?)
• lights? will it be dark in the work area under that wide shelf
• shallow and wide drawers under the working-surfaces? for e.g. SMD organizers (mini-boxes)? or keyboard/mouse

I'll take a 2-module wide unit, with oak surfaces please 

[H.O]

Massive bench! Are you going to anchor the backside of it to the wall? If not I think you'll need some bracing.
Depending on the type of fastners used to attach the pieces to each other you might want to add some brackets to support the horizontal pieces onto which the worksurface rests. I know I wouldn't want that thing to colaps on me.

I take it you're ordering the pieces cut to length?

And, as has been mentioned, I would look into how much sag you'll get on a 2m long 45x45 but it sounds like you might already have done that.

Looking forward to see the build!

[Muttley Snickers]

The shelves on my twenty year old storage racks are 1800 x 600 and rather than use MDF or Plywood I used Melamine instead as it was easy to keep clean, not affected by surface water and less prone to warp. Price wise it was about the same as the other options anyway. For those not familiar melamine is laminate covered particle board as used in kitchen cupboards.

[PTR_1275]

Looks good TiN. It would be easy enough to put in extra braces under the shelving where needed too. I would be a bit hesitant having that much weight on such a large area of shelf without extra support under them to stop bowing.

Looking forward to seeing how it all ends up

[nctnico]

@Tin: You'll need to add ways to make the frame stiff (like closing up the back and sides at least partly) otherwise the whole thing may flex and even fold / collapse in on itself.

[Renate]

Melamine is too thin for my taste.
I had a cheap desk that used that and it gouged pretty easily.
The layer can be as thin and cheap as shelf paper.

For a work bench (or even just a desk), I suggest Formica (TM) or other plastic laminate.
They are tough and don't mind alcohol or the occasional solder blob.
You need to contact cement it down, route the edges.
You can either use plastic edging hammered into a slot or laminate them too.

A 2 meter span is large.
It would complicate your multistage design, but for many of your positions you could do it differently.
You could have supports every meter (with an offset of 0.5 meter).
This would leave a clear one meter section in each position for your legs.
This would also compartmentalize areas for storage on the bottom, drawers, cabinets, whatever.
You've got a lot of space there that is not being used.
You could dispense with the whole top layer of your design.

I'm a big fan of 1" square aluminum tubing.
For vertical members it's plenty strong.
They also sell it with slots so that on the bottom you could add "vanity panels".
Even a 1/4" panel in the assembly adds a lot of rigidity.
https://www.mcmaster.com/structural-framing/=25f3da55d1bc41db84542ac8f5749febk5azxob1

I'm typing this on a two meter desk with four legs a meter apart, 3/4" plywood with laminate, two side panels of 29" x 24".

[Kleinstein]

Near 2 m span is quite a lot with heavy instruments / supplies. So there can be quite some bending.

I would not like the beam or full depth board in some 1.7 m high over the desk. It probably would not take long before it gives you a headache.
One would have a hard time to use the full depth of the upper boards anyway.

For stability some diagonal connections are needed, unless firmly bolted to the wall.

[Muttley Snickers]

Melamine is too thin for my taste....I had a cheap desk that used that and it gouged pretty easily...The layer can be as thin and cheap as shelf paper.

I suspect that there are different grades which all fall under the name of Melamine, the stuff I used is 16mm thick and has a slight grain or textured surface which has stood up well to all sorts of abuse.

[wraper]

IMHO not recessed top shelves will suck big time. Besides all obvious downsides like obstructing view and accessibility of any equipment standing on it, it will also block light coming from top. So you will be working in a sort of dusk. If you add local lighting, it will sit in front of your eyes, partially shining directly into them. Decent lighting should be way above your head.
About monitors, sitting in the middle of tho monitors placed under angle is not good in my experience. You won't be able to observe both of them simultaneously anyway. And to switch from one to another you will need to turn your head. As both of them are in sub-optimal position, it will suck even if you choose the main one. You'd better sit in front of one under straight angle. Second monitor placed under angle for secondary tasks, on the left side if you are right handed. Not to say 43" may be way too big. Don't suggest going above 32-34" unless you really tried this in practice and find satisfactory.

[ogden]

I would use generic electronics lab shelving, without structural elements dividing work surface into strict sections. Like in this TI video. Also good idea to make heavy system supplies mobile - put them below table, on trolley(s). [edit] Don't forget "service" PC for rework/assembly area. It could be small netPC with 22" LCD on articulated arm.

[Yansi]

@Tin: You'll need to add ways to make the frame stiff (like closing up the back and sides at least partly) otherwise the whole thing may flex and even fold / collapse in on itself.

If he is supposed to make it from the industrial strength grade Alutec like we use in EU for building industrial equipment with, it won't budge.  Maybe couple mm if you sit in the middle of it.

Pretty hefty stuff, also VERY expensive.

According to a calculator provided from one manufacturer I am used to, a 2m long section will budge just 5.8mm at 100kg load in the middle.  I'd say good enough. You will never have that much load on it.

[RoGeorge]

The design looks great!   

That's exactly how I have it organized, mine is only 3 benches with shelves above, and chairs at bench 1 and 3:
- first bench with the PC monitors
- second bench the instruments (oscilloscope, generator, power source, etc) so they can be operated from either bench 1 or bench 3
- third bench is for soldering tools, microscope, etc

Storage is everywhere in the room, and some other shelves on another wall.

What I miss is a monitor on the 3'rd bench, to keep a schematic or a datasheet display while working, but it will cover the storage shelves, so I'll not put another monitor there unless I'll found a good and strong suspended boom arm for a small monitor.

The biggest drawback for now is the window is on the left side, so natural light is at the first desk instead of the 3rd, exactly opposite than how it should be.

To me, a circular cutting in the middle of the desk would be a big disadvantage, since many times I end up having the board I'm working right on the near edge of the desk.

[Renate]

Sitting in the middle of two monitors placed under angle is not good in my experience.

I agree! You are always just looking at the crack between them. That's why I have three.

[jogri]

Have you ever worked on a 1.5m deep bench? Even if you have full size, 50-60cm long test gear it would be uncomfortable to use it: You can reach 70-80cm without leaning forward, and if you have 1m between you and your gear you are going to hug your DUT every time you want to adjust something.

The same problem applies to your cold storage, you won't be able to reach most of it without using a ladder.

Btw, you should probably screw down the legs, should be rather easy if you install a 90° angle and screw it to the ground before dropping in the horizontal beams.

[Conrad Hoffman]

Seems like a good way to go if cost is no object. At work we build a lot of things out of Minitec rail and it's strong as heck. It helps that the Minitec warehouse is only a few miles away. Good ideas above. I had my (wood) bench built deep, but only about a meter. That's enough for my boat anchor HP meters and stuff. Deeper would be a problem. I have some holes in the back with plastic inserts for power cords but integral power strips might be better if they had enough outlets. Agree about the shelves above killing the light.

[TiN]

Wow, lots of feedback. To reply on some of concerns:

Stuff on top shelf would be rarely needing front panel/knob access. Part of the reason is that everything in lab interconnect via GPIB or LXI bus. So far I often find large gear like PSU or parametric analyzer occupy valuable working area space while running days long experiments. Some of my gear need 63-65 cm depth, plus cables plus space for airflow for cooling fans.

Moving gear out can help to resolve this issue.
LED panels would also be installed on top shelf's inside surface,as well as ambient lights. LED panels, such as 60x60 cm ceiling type are one of reasons why I thought to make top shelf as deep. To mount light out of sight if one sits in normal position, looking forward.

Top shelf perhaps bit too wide, so I'll see if it's better to reduce it slightly in. I was hoping to keep frame like a box tho for better integrity. Most of heavy gear will live on working bench level.

For monitors, I spent a decade with 30+24 or 30+20+20 setups until moving to single 43" 4K monitor. Day and night improvement, life without bezels and 4K resolution with Windows scaling 100%. 32-34" is just too small for 4K. There will be small 24" FHD screen in assembly/rework area. And fume extractor as usual.

AC power cords, Ethernet cables, switches, UPS stuff, all that will go to top shelf. Only smaller power distribution board would be installed on two middle sections for daily work.
I don't draw all that yet, as it would be Phase 2 of the project, when refining apply.

I am rather tall person (almost 2m) so large legroom space is paramount for me. This means no drawers, no shelf or anything like that under the workbench. Hate to bump into stuff when move from one side of the bench to another.

[RoGeorge]

The depth from the front edge of the desk to the instrument's front panels (or upper shelves) in my benches is about the length from the elbow to the tip of the fingers, and is a little bit too much.  Making it even deeper will be very uncomfortable to use.

About multiple monitors, I noticed that having 3-4 of them doesn't really make one more productive.  I prefer one big (32'' 4K or bigger right in front, and one lateral smaller monitor on the left.  The left monitor is only rarely used, a big diagonal 4K or so can display more than enough windows to work with.

Having a 3rd monitor on the right side is not an option for me, it will stay in the way while fiddling with the instruments or with the device under test while staying at the PC.

[Brutte]

Got tired of piling equipment on top of each other (..) decision was made to go with T-slotted aluminum extrusion to work as a structural frame, with plywood/MDF sheets for shelf and bench-top surfaces.
(..)
Ideas? Suggestions?

I do not like the concept, because:

1. The 2m wide span requires a stiff beam to span under your MDF. You have decided to put this stiffening beam just above your thighs.  Take a piece of that extruded beam and glue it under your current desk, just near the edge. Any conclusions?

2. Putting vertical supporting legs just in between sections is also unfortunate. You cannot move from one section to the other without sliding out the chair and bypassing it.

3. This design has very low stiffness for any shearing forces. It will collapse under its own weight. You have to redesign it.

4. I suggest you should think over the way this construction behaves on overload. If it collapses by plastically straining one member and then stops then it is fine. However, if the design is to fall apart completely on failure of single connection then I would not use it to keep my gear there.

How about fastening some trusses to the back wall?

[SparkyFX]

The overhang top shelf is great to install lights underneath and have good workspace lighting. However you need to consider using connectors between the beams like these, they lock into the slots and stabilize the construction sideways.

[TiN]

Yup, there will be double angle connectors, with 4 bolts on each junction side. It's just not shown on 3D model. As well as feet pad on bottom.

Brutte

All sheets are supported by square beams right under. So I don't quite get the number 1 item. For item 2 I don't see any reasonable solution otherwise, since total length is 8 meters, and load on main bench would be about 400kg.

[TiN]

To go back in time, back 10 years ago, I had similar idea bench but much simpler in construction and design. It used vertical beams from hexagon extrusion, and angles to mount shelf and bench.
Depth of that bench was 1.1m and it was very nice to use, but I didn't have large instruments like now. Width of segment was 1.37m and there was zero support under. Laminated MDF did sag but bench didn't collapse on me after daily use for 2 years 
I found old images from server for reference:





Beams:



MDF sectors with laminated surface



Mounting hardware



Shelf support:



Assembled:



Workbench with monitors (Dell 3008WFP + two Dell 2007FP in pivot)



Middle shelf.



Obviously this design wouldn't survive the new needs, hence I go with much beefier aluminum system and full square supports under working areas, and reduce from 2 shelf to 1 shelf build.

[free_electron]

nice
.
i like the cutouts in the workurface

i built mine from three ikea jerker tables that i added in front of breadracks

[TiN]

Added junction connectors, reduced depth of top shelf and minor tweaks.