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

[floobydust]

I found 80/20 T-slot expensive which is OK if I'm getting what I want. But the deciding factor was doing shelving. Just the usual screws and nut and bracket at each corner which cannot take much shear and high cost per joint. Then you need a level and tape measure at each corner. Even complained to the 8020 Co. that they have no decent shelving solution in their ecosystem. The cost per shelf was the project killer for me. $10 per bracket plus screws, nuts and I couldn't justify it.

If I was to go further, I would find a way to mount Knape & Vogt (KV) adjustable shelf brackets (pilasters) in the pillars. They are low cost metal strips and at Home Depot etc., and go with with wood shelves.

I also complained they have no 80/20 power bar solution because just mounting a i.e. Hammond strip is just too much hassle. I need an extra worth $20 of fasteners per power bar?
Get the fasteners from china and save $100's of dollars, or even extrusions on a custom shipment. It can also be cheaper to CNC machine some pillars and use anchor fasteners.

In your layout, my knees would constantly hit the pillars on either side of each bay. I would move them back in. You would not have elephants on the shelves. Put pegboard panels in there to hold cables or some tools. Lighting is something else to think about.

[TiN]

You would not have elephants on the shelves.

I will have ~100-150kg (330 lb) constant load on each section, so prefer to overdo in this particular case. Sadly this is was not planned as low-cost project by any means, but lab requirements justify it.
After all, this is planned to serve me for years and years.

[richnormand]

I did a similar setup in the past. On the back I used stranded stainless steel wire in an X pattern for each section with an adjustment turnbuckle at one end as diagonal tension members.
It stabilized and greatly stiffened the whole structure. It also allowed fine adjustments to get the whole thing squared properly and leveled once on the floor.

Also do not forget proper ground and and ESD precautions (for the electronics area)

As far as sagging shelves under load I used L-shaped "dixion" lengths bolted underneath the shelve. They resist bending very well, are cheap and are available in long lengths. Makes a nice way to mount rack equipment and hang stuff from too.

[nctnico]

Also think about cable ducting. I have an open slot at the end of my desk with cable trunking underneath.


The power distribution is a project in itself.


In total I have over 100 mains outlets under my work bench.

[cncjerry]

how much are those t-slot sections and how much weight can they hold over 4ft span?  I have a cabinet that i want to bridge across because the weight of my new spectrum analyzer will collapse the top preventing the top  drawer from closing.  The cabinet is about 42" wide.  I figure if I can build around it I could use the space.

Thanks

Jerry

[ebclr]

This thing is cheap,  strong and " programmable " 

https://www.amazon.com/AmazonBasics-3-Shelf-Shelving-Unit-Chrome/dp/B01M0XLTT5/ref=sr_1_13?keywords=Chrome+Wire+Shelving&qid=1578903111&sr=8-13

Make a regular table and put this shelf on top

[RoGeorge]

For "programmable" and zero tinkering, I'll recommend the IKEA ALGOT system.  That is what I use now, and since I don't have any boat anchor instrument, it's more than enough.  The heaviest instrument I have is a Rigol DP832 power supply of about 9 kg.

https://www.ikea.com/ro/ro/catalog/categories/departments/bedroom/22798/

In the link there are only suspended rails, but ALGOT has pillars and standing legs components, too, so it doesn't need wall anchoring.  So far very happy with it, strong enough, nice look, and can have shelves on the both sides of a pillar.

[DBecker]

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.

Errrmmm, what material do you think that Formica(tm) is?

(Answer: it's a melamine laminate.)

Making this relevant:
The name ForMica comes because melamine infused paper was originally used to replace mined mica in capacitors and electrical insulators.  It's properties are not as good as mica, but it enabled making better inexpensive rolled "paper" capacitors.  Real mica is still used in capacitors that must be stable at varying or very high temperatures, while Formica stopped being used long ago.

[Renate]

For a work bench (or even just a desk), I suggest Formica (TM) or other plastic laminate.

Errrmmm, what material do you think that Formica(tm) is?

(Answer: it's a melamine laminate.)

Erm, well, you got me there.
Still, looking into this, "melamine boards" are LPL, low pressure laminate.
Formica or Wilson Art are HPL, high pressure laminate.
I measure what I used on my desktop as 1mm thick.
Can somebody tell me how thick the facing on their melamine boards are?

Then there is the question of the substrate.
I don't like, won't use particle board, it's not good around moisture.
(Yes, I know you have facing and banding on it, but liquid can get into the edges and make it swell.)

I get a wider choice of colors with HPL and I can band the edges, also curves (as shown in my photo).

[Shock]

I made a post about surplus Rack PDUs being a viable option for lab power in the below link. In my main 2400mm bay I have up to 48 individually switched outlets. The PDU supports staggered powering, switched groups, shows loading etc.

https://www.eevblog.com/forum/reviews/lab-shelf-power-solution/

I use long span shelving and it's basically the same thing you are doing but the industrialized kitset version. I have in total about 13 cubic meters plus benches. I've probably spent about $500 all up on it including power and cabling.

Not meaning to be rude but the weakness in your design I noticed was lateral movement when fully loaded with an uneven distribution of weight. Front and backwards you are fine but sideways it's a collapsible box depending on if the system is free standing and how the desktop is secured to the uprights.

To illustrate this imagine shoving it hard from the side. Hopefully the interlocking system or desktop will hold it from moving sideways but I would put a few diagonals in the lower bottom so that lateral movement bears weight on the diagonals before the interlocks.

Anyway here is an image of 600mm deep longspan, you can make it as deep as you like and size the upright support horizontal and diagonals accordingly. As already mentioned shelf sag becomes an issue so to avoid that you they sell horizontal shelf support bars. Shelf heights are fully adjustable.

[DBecker]

For a work bench (or even just a desk), I suggest Formica (TM) or other plastic laminate.

Errrmmm, what material do you think that Formica(tm) is?

(Answer: it's a melamine laminate.)

Erm, well, you got me there.
Still, looking into this, "melamine boards" are LPL, low pressure laminate.
Formica or Wilson Art are HPL, high pressure laminate.
I measure what I used on my desktop as 1mm thick.
Can somebody tell me how thick the facing on their melamine boards are?

Then there is the question of the substrate.
I don't like, won't use particle board, it's not good around moisture.
(Yes, I know you have facing and banding on it, but liquid can get into the edges and make it swell.)

I get a wider choice of colors with HPL and I can band the edges, also curves (as shown in my photo).

There are many types of fiberboard.  Low end types act like desiccant-filled sponges, swelling even with modest humidity.  Some claim to be rated for moist areas (e.g. residential bathroom cabinets), but they still don't do well with constant water exposure.  You want an "enhanced MDF" backing at minimum, not "particleboard".  If you require formaldehyde-free products, you may need to compromise on other characteristics such as moisture resistance.

[rhb]

Interesting thread with some good ideas.  In my case I'm building an RF bench rather than a metrology bench, so very different requirements.  RF gear is very heavy and requires a huge number of special cables and other paraphernalia.

I am just starting on the design of a 16'  bench for my new lab area.  To provide easy access to the rear of the instruments  and wall I plan to have casters under it and toggle legs that lift it off the casters.   Very similar concept, though no cutouts and I'll use cabinet grade plywood for the top and shelves rather than MDF.

The aluminum extrusion is very nice, but as noted,  expensive.  Instead I plan to use square steel tubing and angle.   Naturally, that will have to be painted.  I'm going to cantilever the bench top supports between the end sections.  The cantilevers and a few other components will probably be welded, but most things will be bolted to allow for changing requirements.

To provider good air circulation full width instruments will sit on angle rather than a solid shelf.  I'm also considering baffle panels and muffin fans to pull air through the instrument stack and exhaust it towards the ceiling.  Instrument power will be supplied using EMT and flex all the way to the IEC connector as with my current bench.  That has proven very satisfactory, though I made the initial instrument feeds a bit short and it's a hassle to reconnect an instrument if I take it off the shelf.  The feeds for the new bench will reach all the way to the front of the instrument rack.

To address the shear stiffness issues mentioned earlier I'll have solid end panels which will have a 2nd panel mounted on a 100% extension slide which will store test cables.  So each bench will have a shallow, full height pullout for cables and adapters at each end.

[ramon]

While your design is visually beautiful I think that it is not cost effective and probably not the best option to place your elephants there.

Don't know if you already have ordered that massive amount of T-sloted aluminum. My guess is that it could cost at least US $1,800 just only on 45x45 aluminum (according to grainger and misumi prices). Then you will need add another $800 just only in hardware to make joints. And then add another $900 - $1200 for plywood/MDF. All that without shipping cost. If the extrusion is not cut to exact dimensions then just add another $200-$400 for a mitre saw / blade, and expend weeks doing cuts ... and grinding to match all sides !!!.

A lot of money - and time - wasted when there are already some cost effective solutions on the market :

All production sites use some kind of Laboratory, Packing, Industrial, or just 'steel workbenches' and 'shelving' (nice keywords for google). Of course there is not a complete specific custom solution to the problems that you want to solve, but you can mix them together to get some acceptable solution without not so much money AND time involved.

It is basically the same idea that Free_electron suggested ('Ikea jerker tables added in front of breadracks') with the difference that those (industrial steel) workbenches can handle loads between 1000-6000 lbs.

Does the top shelf need to be 1m deep? I think that is not a good idea. You would soon won the lottery to start having backbone problems ! Definitely not good idea to place big stuff there. Boatanchors better on separate shelves (unless you use them daily), and if on bench then make sure you have some smart way to move/slide them with ease.   

Think that you can also place two shelves at the sides of the workbench (with the same deep than the workbench, or shorter) and plywood across shelves to make the top rack. You will need some kind of supports that are already being sold as accessories (check grainger workbenches accessories section). You can check Tennsco 'bulk rack shelving' frames that is actually the same steel framing that Shock have shown.

Some links to check pictures and maybe get new ideas:

Workbenches:

https://www.cisco-eagle.com/catalog/category/244/workbenches
https://steelsentry.com/workbench-furniture/rd-workstation/
https://www.uline.com/Cls_41/Packing-Tables-and-Workbenches
https://www.uline.com/BL_3853/Industrial-Packing-Tables
https://www.uline.com/Grp_537/Steel-Workbenches
https://www.uline.com/Product/Detail/H-7698/Steel-Workbenches/Steel-Assembly-Table-Standard-72-x-48
https://www.fishersci.com/us/en/products/J461FINW/laboratory-benches-tables.html
https://www.nationwideindustrialsupply.com/workbench/
https://www.nationwideindustrialsupply.com/departments/tables-work/tri-boro-work-master-work-benches/
https://www.nationwideindustrialsupply.com/departments/work-benches-ergonomic/channel-leg-work-bench/
https://www.grainger.com/category/material-handling/workbenches-and-accessories/pre-configured-workbenches-and-worktables/fixed-height-workbenches
https://www.grainger.com/product/GRAINGER-APPROVED-Workbench-7D180
https://www.grainger.com/product/GRAINGER-APPROVED-Workbench-7DG17


Shelving:

https://www.tennsco.com/Category/shelving
https://www.tennsco.com/ProductsBySubCategory/bulk-rack-shelving

[TiN]

None of the standard benches support depth of calibrator and another 19" instrument in front of it + space for cables, accessory etc.
And aluminum profile with hardware will be arriving next week anyway. Yes, it's not cost effective at all, but it wasn't supposed to be.

[ramon]

Oops, then too late ... 

But they are available. 1.2m (48") deep workbench is available on those links above (model H-7698, 72"x48", adjustable height 28-48", and 2000 lbs capacity for $450). Nothing stops you to extend the depth to 1.5m if you put a custom board over it in the same way you have planed your bench (to still have available those semicircle cuts).

You can also check the sagulator ( https://www.woodbin.com/calcs/sagulator/ ) if you haven't done yet, to check yourself why I suggested time ago plywood instead of MDF (and you can still cover it with any material you like, plywood with laminate should be a very easy material to source.).

The 'semicircle cut' idea could have been expanded further and converted into a U-shaped working area in the following way:
   
   Area #1 : Workstation; R+D; and Rework. Three sections into one U-shaped (working) area, plus
   Area #2 : a separate (mechanically independent) calibration/long-term-testing area. (if not a separate room, or EMI closed rack ! Yes, I know you dislike racks as much as banana jacks, but they have it's reasons to exist)

Your drawing shows a depth of 1.2m + space for chair, so I suppose that you have enough space to make a U-Shape possible. Otherwise you expend your time walking along your room. A U-shape doesn't mean that all three working sections need to be joined close to each other. They need to be close, but not too close. Also I don't mean that they need to be mechanically connected in single beautiful rectangular frame (in fact, you'd better have them not connected). And that is what I wanted to point out ...

Cost/time effective or not is secondary issue. Main concern is that you don't need a single 1.2m or 1.5m deep bench. In my opinion that not only is not needed, it is not desirable.

Having a calibrator or any other big instrument on a shelve on the wall, and one or several separate workbenchs in front  (with a small gap between them) could be better. This way you don't transmit any mechanical vibration to the calibrator (or any other sensitive instrument). And if front bench has wheels, you can handle better how you access that heavy stuff at the end. There are workbenches with lockable casters that can move freely when you want and stay fixed on one place wherever you need. Yes, you said those boatanchors will be there permanently, except when you need to get them back and then once every 2 years you will get annoyed by this (and I hope that to be your only issue, take care when handling heavy stuff).

Many times I found myself needing extra items or instruments around and then I add movable shelves/racks/whatever to the sides to have all items nearby at 'elbow' distance (something that somebody pointed out before). That is nontrivial If I want to be time efficient, and that is usually most of the times.

Enough said, I hope you enjoy your dreamed bench for a lot of years.

Please don't take this as a negative comment. I hope it could help you, in case you need a new bench 10 years after this one.

The pegboard panel that was suggested is a good idea too for cables and common accesories. Much more if there are 'sliding pegboards' (check that on google images, or here -> https://www.fixturescloseup.com/2019/11/21/high-density-sliding-pegboard-display-details/ ). Rotary shelves are nice too for small items, but expensive.

Are all the aluminum rails already cut to size or will they deliver in bulk and you need to cut them?

[richnormand]

Another thing I have found most useful over the years with deep shelves (assuming available space permits it) is to have rear access to all the bench length.

This allows you easy access to rear cabling of the instruments (in particular when instruments are stacked on top of each others and you need access to the rear panel of the bottom one) and some out-of-sight storage space.
Particularly for the posted designs where the bench is fairly long and against the wall.

[TiN]

ramon
I didn't order plywood/MDF yet however. Thick plywood in large sheets is not very common, so would be pricey for that as well. Will need about 500 sq.ft. of it.

One other point most of usual benches/tables miss = adjustable height for shelves/tabletop. Design with T-slots allows that, and allows adding shelves fixtures without moving anything else. Sure, this flexibility comes at cost, but I missed this a lot.

I've used this concept, but with 19" 42U rack with oscilloscopes/PSUs/etc and movable table in front of it for DUT. Didn't like it at all...  More than once I connected all probes/wires between rack mounted gear and DUT PCB... then somebody knocked on table - it moved few centimeters, and hello.. wires and connections to PCB ripped clean off, changing development project into repair project  So I don't want anything moving on the bench.

Don't mind little moving around, it's good to have exercise at the lab, instead of sitting idle for hours   
I've thought to make non-connected benches. Still have this ability with extrusion, just unscrew few bolts, add two beams and have two dual-section benches, eh?

Current layout does not allow for U-shaped stuff.

All aluminum hardware ordered precut to length, so hopefully it would be all plug and play. Delivery is about $250 for all this (~150kg of stuff).

Pegboards, power delivery routing, lighting, tools fixtures will be niceties to work on after main structure is built. Need to experiment with few layouts first to see what works, and what doesn't.

[chickenHeadKnob]

Another thing I have found most useful over the years with deep shelves (assuming available space permits it) is to have rear access to all the bench length.

This allows you easy access to rear cabling of the instruments (in particular when instruments are stacked on top of each others and you need access to the rear panel of the bottom one) and some out-of-sight storage space.
Particularly for the posted designs where the bench is fairly long and against the wall.

This ^^^^!, if you can at all arrange it. It is pure joy to work in environments where the benches and racks are at 90 degrees to the wall instead of against it. I have done both and there is an obvious winner.

[TiN]

Today is the day. Got 230kg of aluminum goodness. It's more heavy-duty than I expected. All main bench beams will be supported by dual angles, with four M8 bolts each.

Assembled one section to get feel of the dimensions/sizing. It feels super-strong even in such most unstable configuration, without sides to support. Once I have all sections interconnected, it will be like a tank. Each beam is about 4.5kg. Need to buy some hardware and M12 bolts for feet and such.

Depth is perfect. With boat anchor gear like calibrators, linear power supplies, Tektronix scope/analyzer I have good amount of working area space and still can reach controls/knobs of the instruments.

Next step, order working surfaces out of plywood. Will be not cheap either, as standard 4x8' sheet are not going to fit my sizing.

[floobydust]

 

[beanflying]

Mmmm Shiny in a matt sort of way 

Make sure you are a bit careful with the ply you choose more laminates in the board is generally better and you also preferably want an A or B face grade on one side at least so look for AB would be sensible price to look for. A for up and B for down. When you get lower in grades into C's and D's there may be holes in the faces or the face may even be bogged with filler.

[TiN]

Got some proper M12 bolts and screwdrivers for assembly.
Got one more section added.



Just to illustrate the area available put some pressed wood panels. 24" monitor looks tiny on the bench.



This black ESD mat is 2 x 4 ft size.
Will be moving equipment away tomorrow and finishing the complete frame.



View under for stiffener beam. I have few extra extrusion beams, so I can reinforce one or two sections where I plan to put lot of heavy gear.



Next step is fine-tuning plywood desk drawings and ordering that to custom cut from 5x10' panels. 

[Shock]

Looks good, time to put the feet on. What vertically holds the weight of each shelf aside from the combined angle bracket clamp tension? Does it bite into the uprights at all?

[TiN]

Uprights?
The frame design shown on first post 3D card image.
It will be very close to that after assembly. Bottom short beams (at leg level) most likely will not be installed, after assembly I feel those are not necessary.
I tried to load middle of the single long beam on section 1 with 110kg today and barely detected <6 mm deflection. In actual use there will be much better load distribution always between 5 beams and plywood.

[Shock]

A length mounted vertically is called an upright.