Stacking test equipment - Page 1
Forum section: electronics / testgear

author: Grandchuck
author_rank: Super Contributor
timestamp: July 16, 2019, 03:05:24 pm
content: Hello all,I have seen photos and videos of stacked gear. I would like to stack two fairly heavy items on top of a 3458A DMM. Are there any guidelines? The two items are an HP 8903B (26 lb) and a GW Instek GOS-6103 (18.4 lb).Thanks!

author: tggzzz
author_rank: Super Contributor
timestamp: July 16, 2019, 03:12:21 pm
content: I doubt you will get a definitive answer.Sooner or later you will want to access the bottom instrument without disturbing those above.Consider getting a 19" rack, or similar.

author: edavid
author_rank: Super Contributor
timestamp: July 16, 2019, 03:21:21 pm
content: There's no general answer, but I don't think HP ever made a cabinet that couldn't stand up to a mere 44lbs of equipment stacked on top.The other question is whether you are in an earthquake zone

author: med6753
author_rank: Super Contributor
timestamp: July 16, 2019, 04:11:25 pm
content: Agreed, no general answer. If you decide to stack equipment be cautious and mindful to maintain proper ventilation. First hand experience here. Had a Tek 2430 stacked on top of another piece of equipment and didn't realize that some critical underside ventilation holes were blocked. As a result it permanently heat damaged 2 CCD hybrid modules. Lesson learned.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: July 16, 2019, 04:20:07 pm
content: If you open up the equipment, you would realize there is zero internal cross bracing or vertical support where the standard Agilent plastic feet would rest on top of, and you are only relying on the metal shell.I don’t stack equipment more than 2 high. I am using multi level shelf now, and switching over to professional 19 inch rack enclosure with internal fans when the new home lab is built.I doubt there’s a definitive answer, but why risk ruining expensive test gears for taking short cuts.If you want a less involved approach, stereo cabinet could also work well.

author: DaJMasta
author_rank: Super Contributor
timestamp: July 16, 2019, 05:51:49 pm
content: You can get a feel for how well things are going to hold up to it just by picking it up and seeing what shifts or bends. Most equipment should be no problem to stack at least one, probably two layers deep, but sometimes feet position, sizing, or the thing's weight get in the way of that.I try not to do more than 3 tall, and if they're tall/wide, I generally only do two (three works with those half width, half height stuff like DMMs just fine). I always try to keep the heavier instrument lower and keep the heaviest ones directly on the desktop. Beyond that, I try to setup a layer of durable shelving, then stack more on top, since then the weight of the stuff on the upper level isn't just pushing on the lower equipment.A rack is definitely a good option, but it's a big chunk of furniture and can be a fair bit of extra expense finding rack mount hardware or shelving.

author: tkamiya
author_rank: Super Contributor
timestamp: July 18, 2019, 05:48:57 am
content: Proposed two equipment are fairly light. I'd doubt you have any problem. Having said that, doing so will make maintenance a night mere after third and forth one joins in.In my case, after doing for few weeks, I quickly moved to wire rack method, then to 19" rack method. They are pretty cheap on Amazon. Sure, they are not as sturdy as HP or other name brand version. But it's quite sufficient for my purpose.That's what I recommend.

author: Grandchuck
author_rank: Super Contributor
timestamp: July 18, 2019, 05:28:34 pm
content: Stacking delayed! Tried to clean the air filter for the 3458A and it fell apart. New ones on the way. While waiting for those, will give consideration to your replies. Good thoughts all. Thanks folks!

author: Gyro
author_rank: Super Contributor
timestamp: July 18, 2019, 06:15:17 pm
content: If all else fails, read the manual!I think most test equipment manuals are fairly explicit, both from the mechanical and cooling perspectives.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: July 19, 2019, 02:03:50 am
content: Does anyone know which shelves Shahriar has? They look sturdy and nice.

author: 0culus
author_rank: Super Contributor
timestamp: July 19, 2019, 02:13:47 am
content: I've never had any problems stacking HP equipment. It was designed to stack. Heavy stuff on the bottom, lighter stuff on top. I agree with the person above that the ideal solution is a rack. I may get one in the next year or so.

author: DaJMasta
author_rank: Super Contributor
timestamp: July 19, 2019, 02:25:38 am
content: Quote from: jjoonathan on July 19, 2019, 02:03:50 amNot sure (maybe he'll see it and say), but for a while Ikea carried a set of legs that looked like that, I have a shorter set that I really like but wish were taller for other stuff. I think it was part of a configurable shelf system where you could buy various legs and various shelves and set them up however.

author: Berni
author_rank: Super Contributor
timestamp: July 19, 2019, 05:30:09 am
content: Its not that much of a problem to stack old sturdy HP gear. Id say you need to put >100kg on top before you would get any issues.The feet tend to be towards the corners so the weight is being applied to the sturdy upright parts of the thick metal case and some HP gear has a small grove along the top of the front bezel where the feet or other gear of matching groves on the bottom of the front bezel fit. Once it falls into the grove the two piece of gear become locked together and will not slide off anymore. So the engineers at HP intended them to be stacked if they designed in a mechanical feature for them to lock together like that. The HP gear usually does not have any vent holes on the top and bottom, but there are a few exceptions (Just use common sense to not completely block any vent holes).26lb is actually not that heavy for old rack sized test equipment. Most old RF gear or big PSUs are heavier than that. For example i have an HP 8566B spectrum analyzer that weighs about 50kg, but because this is too heavy to be easily moved they split up the display and RF section in two parts that stack together. Okay the top display section is less than half of the 50kg weight, but the bottom RF section has no special design for stacking, its just the typical oldschool HP "slidey cover" case design.If you plan to get a lot of large rack sized test gear i recommend getting a old server rack. You can likely find one used locally and some even come on caster wheels to allow the hundreds of pounds of gear to easily be moved around. But there is also the ever so popular series of Ikea tables that happen to be the same size as a 19 inch rack:https://wiki.eth0.nl/index.php/LackRack

author: TheSteve
author_rank: Unknown
timestamp: July 19, 2019, 05:37:28 am
content: This says it all...

author: Berni
author_rank: Super Contributor
timestamp: July 19, 2019, 05:45:27 am
content: Okay... well i might not recommend stacking it quite that high.But mostly for the reason that some equipment feet slide really easily on top covers, so bumping a piece of gear a little to much could cause it to slide off to the side enough for a foot to come off and if that happens towards the bottom, then the whole stack come could start leaning and topple over. Not only an expensive disaster but also potentially quite dangerous if it ends up falling on you.But then again the guy in the photo is a professional volt nut, he knows what he is doing, especially if it involves 8.5 digits.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 19, 2019, 10:30:07 am
content: Quote from: TheSteve on July 19, 2019, 05:37:28 amIts a mess, a total mess, i would have done somekind of rack mount system right away, not piling up like this ??

author: nixiefreqq
author_rank: Super Contributor
timestamp: July 19, 2019, 10:45:14 am
content: wimps!

author: Mr. Scram
author_rank: Super Contributor
timestamp: July 19, 2019, 10:53:09 am
content: Quote from: coromonadalix on July 19, 2019, 10:30:07 amYou buy a handful of 3458As and tell me whether you have cash for a rack mount system left.

author: coromonadalix
author_rank: Super Contributor
timestamp: July 19, 2019, 11:34:12 am
content: You can do / build / invent a rack mount for very low $$$ take some L shaped barsyou dont need to shell huge cash for a real rack ?? in my town, they are nowhere to be found.Ive done a similar thing for 40$ of metal, each bar can support around 60 pounds ... and a drill ? (4 bars at 12 feet long each)Unless its a war of stacking equipment loll with the latest photo

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: July 19, 2019, 11:57:12 am
content: I would say this depends a lot on what you are staking. Most of the top-of-the-line equipment is 19-inch wide. their side walls are also kinda strong since often they need to take the stress of a 19-inch rack mount at only the front. So you can stack 19-inch gear pretty high without any issue, as shown in TheSteve's picture of TiN's setup. But I think it is far less of a good idea to stack a tall stack of half-rack equipment on top of a full-rack-width thing, because then the top cover of that bottom thing is taking all the weight.

author: bitwelder
author_rank: Super Contributor
timestamp: July 19, 2019, 12:49:03 pm
content: Quote from: DaJMasta on July 19, 2019, 02:25:38 amThose looks like Ikea CAPITA feet (although I'm not sure if they are still selling such 'tall' models).

author: HKJ
author_rank: Super Contributor
timestamp: July 19, 2019, 07:27:20 pm
content: I do not mind stacking equipment, but I do not put heavy equipment on top of light equipment.There are two pieces of heavy equipment in the picture and they are at the bottom of a stack.The picture is a bit old, the center stack is two devices higher today.

author: Kinkless Tetrode
author_rank: Regular Contributor
timestamp: July 20, 2019, 12:51:58 pm
content: Quote from: Grandchuck on July 16, 2019, 03:05:24 pmAm I reading you right? You wish to physically stack heavy rigs atop the ultra-precise, ultra-sensitive, and ultra-expensive HP 3458A Reference DMM? For some of us, that’s like driving a Ferrari off-road through mud puddles! If I had a 3458A, it would get its own table, no, better yet, it would get its own room to insulate against the ravages of variations in mechanical stress, temperature, and humidity. A 3458A temple where fellow Volt-nuts come to worship and measure their voltage references.And man, I wish I had an HP 8903B as well...But seriously, IMHO, I don’t see a problem with stacking gear, so long as that 3458A stays at the bottom of the TE totem pole so it maintains a consistent temperature, since heat rises..., assuming that you will be powering the gear on and off frequently. And avoid stacking too high so the center of gravity of the stack doesn’t rise too high either. As others say, a rack is best since it leaves some space between rigs for air flow and ventilation, along with no risk of falling over.

author: Grandchuck
author_rank: Super Contributor
timestamp: July 26, 2019, 05:33:52 pm
content: The air filters for the 3458A arrived and they fit almost perfectly.https://www.ebay.com/itm/4pcs-60x60mm-Computer-Mesh-Fan-Cooler-Dust-Filter-Dustproof-Case-Cover-RS/113783990541?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2648It is time to stack!

author: Mr. Scram
author_rank: Super Contributor
timestamp: July 28, 2019, 01:48:23 am
content: Quote from: shodan@micron on July 28, 2019, 01:11:26 amAre those racks hanging from the wall?

author: dcbrown73
author_rank: Regular Contributor
timestamp: July 28, 2019, 04:10:27 am
content: Quote from: jjoonathan on July 19, 2019, 02:03:50 amLikely self-built. Those pylons are screw/bolt in. Probably just cut down some stainless tubing.I looked around for a long time and to not only find shelving that was the right size / width / strength. It was difficult and obnoxiously expensive. I ended up building my own for a small fraction of the price.

author: coppercone2
author_rank: Super Contributor
timestamp: July 28, 2019, 07:37:56 am
content: I recommend you levitate your equipment on an air cushion (like skydividing)don't forget the backup battery and generator, the floor is lava after first plug in.

author: coppercone2
author_rank: Super Contributor
timestamp: July 28, 2019, 07:39:57 am
content: Quote from: dcbrown73 on July 28, 2019, 04:10:27 amthose pylons suck

author: Grandchuck
author_rank: Super Contributor
timestamp: July 28, 2019, 04:31:04 pm
content: So, picking up the two upper tier items together sent simultaneous warning signals to my back and brain.Went to the store and bought some plywood and square stock and in about an hour and a half, voila!

author: tggzzz
author_rank: Super Contributor
timestamp: July 28, 2019, 06:13:42 pm
content: Quote from: coppercone2 on July 28, 2019, 07:39:57 amSo does liquipedia