Would this be safe?

[fatlazyhomer]

So I got this 80$ triple monitor mount. The problem is my middle monitor is much more in front than the side ones. I'm thinking about getting some wood blocks and drilling holes in them to get them to align. Would that be a good idea or should I worry about something breaking because the weight will be poorly distributed?

[hunter4u]

why not use longer grade 5 bolts and then a bunch of washers to extend the screens out.

[fatlazyhomer]

That'll take alot of washers, but I guess that could work too.

Whats grade 5?

[hunter4u]

bolts are graded on there strengths, grade 5 will bend some under there stress factor, grade 8 will not, they will just sheer off but it takes alot of force to sheer a grade 8 bolt.....

http://www.boltdepot.com/fastener-in...ade-chart.aspx

there is you a chart, comes in handy when you work on cars and stuff...just dont put any old bolt in something, make usre it can handle what forces are going to it.

[hunter4u]

my reasoning for going with grade 5 is that you going to have a long skinny bolt so leverage will have more force on them

you might be able to use 2 nuts instead on the bolts....
put the bolt thru the hole on the stand part, put 2 nuts on the bolt run up about mid ways, screw bolt into monitor, run one nut to the monitor to keep it tight and one the other way....
I have used copper tubing as well instead of washers when fashioning things., all this is going to depend on if the bolt is fully threded or not.
hanve fun modding!

[fatlazyhomer]

I like the nuts and bolt idea. But do you think having my monitors protruding from the arm like that would significantly increase the load on the arm? I see it as either me extending my arm holding a dumbell, or me extending my arm, holding a pair of tongs, that are holding a dumbell.

[hunter4u]

i am sure it will put a greater load, twist even on the arm. Dunno your solution as it looks like you bought a stand for going wide, not to surround. Not sure if they even make that kind, as i have never been in the market for it, but it might be a thing to look into..

[Spankin Partier]

You will add a greater torque load to the bracket, but you wont increase the weight by much. This will make the monitor want to twist the bracket downwards more.

You'll really have to watch two parts of the bracket to see if it can handle the additional torsional load. The first part would be the expandable cross member that runs between the three monitors. The second part would be the tilting hinge. You can test these by simply grabbing one of your outer monitor and gently (a few pounds) try and wiggle it up and down. If it feels spongy and everything is bouncing around, then maybe its not a good idea.

If it doesn't seem to bad when you do this, it should be fine. But without touching it myself I can't say one way or another. Its pretty much a judgment call you have to do there.

If you're just looking at adding less then an inch spacer, you should be fine. Just remember the formula for torsional load is:

T = F x D

T = Torque
F = Force (weight of the monitor)
D = Distance (distance from the center of the monitor to the cross bracket or hinge)

So looking at that picture and guestimating, you may have about an inch between the monitor and the tilting hinge and maybe 2 1/2 inches between the monitor and the bracket. So adding an inch spacer would increase the torsional load by about 140% to the bracket, yet at the same time it'll double the load at the hinge. Adding a 2" spacer would increase your bracket load by 180% and hinge load by 300% (triple the normal load)! So you don't want to go too far.

It all comes down to the geometry of the brackets and how heavy your monitors are versus the heaviest monitor the bracket manufacturer states their brackets can handle.

[fatlazyhomer]

It seems pretty stable. I don't know... wouldnt 4 separate screws twist and stuff? Wouldnt a solid wood cube be more optimal?

[Spankin Partier]

I just pulled out one of the screws from the back of my LCD. It looks like a M4. Not sure as I don't have proper measuring devices here. It may be an #8-36UNF, but not sure. So don't quote me on that.

The wood block idea should be fine. It may take a little more work to set up (cutting to size, laying out the four holes for the screws, and drilling it - Tip, use the bracket to lay out the holes if you do this). Only other down side to using wood that I can think of, is its soft so you'll need to make sure the screws are tight so they preload the wood.

Beside wood, some small copper tube, or some oversized nuts (as Hunter said) would work just as well. But again, the screws must be properly tightened down.

When designing a bolted connection, its the friction caused by the squeezing force of the screws does all the work. Most engineers never even consider the shear strength of the screws in their calculations. The shear strength of the screws become an extra safety factor.

The tighter the screws are, the less you'll need to have a large block holding everything in line. But if your screws are loose, then any side loading can easily damage the brass nuts built into the monitor (wooden block or not).

But we don't need to really over analyze this. When you put it together, you'll be able to feel if it feels safe or not before you ever let go of your monitor.

[fatlazyhomer]

Well, I just got back from Lowes, they didnt even have m4 screws long enough.

FML!

On top of that, they no longer sell the 6' shelve piece I used to cut my support beam. I don't want a white one cause its distracting. This means I can't even revert back to my ghetto old desk setup since I chopped off that extra foot of the support beam that was protruding out and onto my bed.

I'm basically left with 3 options:

1) Shop around for another shelf piece and pay another 15$ to revert back to my old setup.

2) Get an Ergotron Mount, which is stupid expensive

3) Get a bigger desk

I would prefer option however, which is turn back time before all this monitor mount malarky, but I don't have a delorian that can go 88.

[no2guncntrl]

Wow..Thanks for the link to the chart. That's great.

[hunter4u]

see if you can f ind some threaded rod in the size you need, cut it yourself to the lengths you need

http://www.grainger.com/Grainger/thr...ecatalog/N-8k5

I do not think you are tracking on how the bolts / rod idea would work. I will try and post a pic of the idea when i get time to find some bolts and nuts as a "example" of what I am trying to get you to imagine.

[fatlazyhomer]

Actually I bought another shelf piece and basically got my old setup back. But I am intrigued on the nut/bolt thing, so maybe if it looks feasible, I'll give it a go before putting this on craigslist. However, looking at the lack of grade 5 rods, I dont think I want to risk 900$ of monitors.

[Spankin Partier]

Metric fasteners do not use the Grade system. They use a Class system. They don't work out perfectly, but a Class 8.8 will be similar to Grade 5. Class 4.6 will be similar to Grade 1.

A Grade 1 bolt should do you fine so long as it is a Grade 1 bolt. The problem is Grades 1 thru 4 are not marked so they can easily be mistaken for unrated bolts. Thus Grade 5 is usually specified where assurances are needed after assembly. In this case an inspector can simply look at the bolt and see the markings. If a lower grade was specified, then a paper trail would need to be followed and this assumes the person who put the bolts together grabbed them from the correct box. So its easier to prove the strength of a Grade 5 bolt even if you do not need the full strength of a Grade 5 bolt.

That said, if you used a M4 x 0.7 Class 4.6 studs (similar to Grade 1), they should see over 440lbs of tension prior to even causing them to stretch, and over 800lbs of tension prior to breaking. That is for each stud.

But if the studs you buy are unrated, they can and may fail at well under 100lbs of tension. Unrated bolts and studs conform to no strength standards. Thus you need rated studs one way or another.

Now lets take your wooden spacer idea and four Class 4.6 M4 studs. Drill 4 holes in the wooden spacer for the studs to go through, assemble everything together so the studs are applying 800lbs of force onto the wooden spacer. The four studs can take a combined load of 1700lbs. Subtracting the 800lbs leaves you with still 900lbs of force you can pull on the monitor. The Coefficient of friction between wood and steel is 0.2 or better. So 800lbs*.02=160lbs. If your monitor weighs less the 160lbs, then there would be no shearing for at all exposed to the studs.

So even if you were to only tighten the studs to apply 50lbs of force each, you'll still be able to support 40lbs of monitor.

So taking this worst case scenario, as long as you have some sort of rated studs (and nuts), you will be fine. The weakest point in this assembly will be the threaded holes in the monitors them selves and they can handle them selves.