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CRT Projector Chain Mounting

 
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UncleWill



Joined: 11 Dec 2012
Posts: 400
Location: WashDC area, ViennaVA


PostLink    Posted: Fri Feb 14, 2014 4:23 pm    Post subject: CRT Projector Chain Mounting Reply with quote


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I am thinking of doing a chain mount for my basement setup. I have never done a uni-strut mounting before and would feel safer with something bolted directly through the support beams. Not sure what it is but those very, very long threads make me nervous just thinking about them.

My idea is this:
2 unistruts bolted along bottom of Electrohome--> 4 eyescrews bolted to unistrut ---> 4 quick link --> 4 heavy duty chains ---> 4 quick links ----> 4 eyescrews bolted through wooden support beams.

Suggestions?
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UncleWill



Joined: 11 Dec 2012
Posts: 400
Location: WashDC area, ViennaVA


PostLink    Posted: Fri Feb 14, 2014 4:25 pm    Post subject: Reply with quote

By the way, what is the thread rating for an Electrohome Marquee?
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jeffslife



Joined: 17 Apr 2010
Posts: 4041
Location: ohio usa


PostLink    Posted: Fri Feb 14, 2014 4:28 pm    Post subject: Reply with quote

Steel is very strong. Don't worry.
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ecrabb
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Joined: 13 Mar 2006
Posts: 15909
Location: Utah

TV/Projector: JVC RS40, Epson 5010


PostLink    Posted: Fri Feb 14, 2014 4:47 pm    Post subject: Reply with quote

Chain? How do you keep the projector moving around?

Why do you need "very long" threads? For the mount, or for the process of lifting it?

Why are you worried about thread rod, but not eye bolts or chains?

Here's the deal: Assuming the same size and quality, there isn't a significant difference between an eye-bolt and threaded rod with respect to strength. Look at these charts:

http://www.engineeringtoolbox.com/loads-hanging-rods-d_1341.html

http://www.wemakeduct.com/spec-sheets/Hardware/Threaded%20Rod.pdf

3/8-inch threaded rod's safe maximum is around 600 pounds. That's max working load, so safety margin is already built in. Actual tensile strength is probably 10 or 15 times that.

So, let's use the 600-pound rating. The projector is hanging from four mounting points, so less than 60 pounds on each connection. That gives you essentially a 10x safety factor. Think about it: You could safely hang three projectors on a single piece of threaded rod, and you're worried about hanging one from four pieces.

SC
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mr_ro_co



Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM


PostLink    Posted: Fri Feb 14, 2014 5:03 pm    Post subject: Reply with quote

You are concerned about lag bolt threads directly into wood floor joists or ceiling rafters, not machine threads, right? This is a particularly legitimate concern if it's a new house with engineered wood i-beam joists, which use a very think OSB web and lightweight lumber for the caps - not a lot of material to engage with lag screws. Even if there is a lot of material it's always made me uncomfortable if the material is 2X whatever pine, particularly non-trussed rafters (older houses).

I think you want the ceiling fasteners supporting the load in sheer by going through the joists/rafters crosswise, right? That's always been the way I've done it, usually with large right angle brackets that then connect to unistrut. Do you have this option? It will give you more adjustment flexibility, and you can still hang the projector with eyebolts and chain.

The chain approach works great. It's also a very good way so securely raise and lower the set by yourself with the quick links. I assume you re putting the strut on the projector for adjustment purposes?

Steve

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garyfritz



Joined: 08 Apr 2006
Posts: 10644
Location: Fort Collins, CO


PostLink    Posted: Fri Feb 14, 2014 9:09 pm    Post subject: Reply with quote

Good God I hope nobody is putting lag bolts into engineered I-beam joists. Crabb is right about the holding ability of steel rod and the distributed load of the projector, but I wouldn't feel all that comfortable putting even 60lbs of load on a lag bolt into an I-beam. It's probably still safe but it's nowhere near as strong as putting into a 2x10.
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ecrabb
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Joined: 13 Mar 2006
Posts: 15909
Location: Utah

TV/Projector: JVC RS40, Epson 5010


PostLink    Posted: Fri Feb 14, 2014 10:33 pm    Post subject: Reply with quote

mr_ro_co wrote:
You are concerned about lag bolt threads directly into wood floor joists or ceiling rafters, not machine threads, right? This is a particularly legitimate concern if it's a new house with engineered wood i-beam joists, which use a very think OSB web and lightweight lumber for the caps - not a lot of material to engage with lag screws. Even if there is a lot of material it's always made me uncomfortable if the material is 2X whatever pine, particularly non-trussed rafters (older houses).

Ah, I didn't catch that he was referring to lags at all; seemed like the "all that threads" was referring to threaded rod.

Yeah, I'm definitely not a fan of lag-screws in joists for heavy load-bearing. The quality and strength of the connection is highly dependent on the quality of the installation. I definitely wouldn't lag into a engineered joist flange. The webbing is fine, but there isn't much to the flange, and drilling a 3/8" hole in it is taking away a significant amount of material. I wouldn't worry bout it failing as the assembly is over-designed for that very reason, but any time you weaken the structure, it could get bouncy, make the floor creak, and of course, the floor could deflect more if there's weight above it.

mr_ro_co wrote:
I think you want the ceiling fasteners supporting the load in sheer by going through the joists/rafters crosswise, right? That's always been the way I've done it, usually with large right angle brackets that then connect to unistrut. Do you have this option? It will give you more adjustment flexibility, and you can still hang the projector with eyebolts and chain.

That's essentially what I did, but used square-tube instead of angle, and threaded rod instead of chain. My buddy and I hung on it together before we hung the projector - over 400 pounds of our lard - and it felt sturdy as hell. I'm pretty sure it would have taken well over a thousand pounds - safely, even. Hanging the projector on it was like hanging a plant on a trailer hitch.



SC
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garyfritz



Joined: 08 Apr 2006
Posts: 10644
Location: Fort Collins, CO


PostLink    Posted: Sat Feb 15, 2014 1:16 am    Post subject: Reply with quote

Same with mine. I have two strips of Unistrut on the ceiling, each bolted on with 4 (4!) lag screws. I bounced my 180lbs on each one and obviously didn't budge it. I'm sure each one could hold a ton. Not so sure about the joists, though. Very Happy
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mr_ro_co



Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM


PostLink    Posted: Sat Feb 15, 2014 4:46 pm    Post subject: Reply with quote

My previous house had engineered i-beam joists. I reinforced three of them by sandwiching their webs with (6) pairs of 4' sections of .75" plywood that nested perfectly between the flanges and generously RTV'd them in place and clamped them with through bolts. I then used right angle brackets that connected to those through through bolts, which then provide the support points for the strut that allows horizontal adjustments, with the usual approach of another set perpendicular hanging off the first pair that allows for fore-aft adjustment. I don't like the traditional unistrut adjustable location nut (which may turn with it loose while trying to slide it), so I always make my own either out of really thick aluminum bar stock or steel, which I then tap for a 3/8 faster and run it through with the head captive at the top of the slider. Total overkill, but gives me complete piece of mind, and they slide nicely, making adjustments of a very heavy projector fairly easy.

http://www.curtpalme.com/forum/album_page.php?pic_id=910

Steve

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UncleWill



Joined: 11 Dec 2012
Posts: 400
Location: WashDC area, ViennaVA


PostLink    Posted: Sat Feb 15, 2014 11:26 pm    Post subject: Reply with quote

Didn't expect this much response Very Happy

I don't know all the proper terminology so will do the best I can to explain. We have wooden joists running from the back to the front of the house that hold up the ground level. Half way in between the entire basement, one steel I beam provides support to all the wooden joists. The house was built in 1983. Will post actual pictures later. My idea was to drill into the wooden joists like in the description here:

http://www.curtpalme.com/MountingMethods.shtm

Anyways, I ran the whole idea of mounting the Electrohome through my dad/landlord. He said no f**king way unless we got a professional to do it. Ugh. So today we went out to a video installer in Virginia. We explained everything and were told that the entire setup would be around $1,200. For the entire job, we could almost get a high end JVC that was just traded in. Coming to this realization, we began smiling and laughing out loud in the store. Then the CRT haters took full swing..

I explained to my dad that it really is not that heavy in comparison to all the furniture up above. Looks like it falling on deaf ears Sad

He wouldn't mind a chain mount on the I beam, but that would take some fancy footwork on my end. Plus it would be hanging a bit lower (enough to hit it with one's head) The projector's path would have to clear a lightbulb and an air vent just to reach the screen.

Any ideas or suggestions?
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UncleWill



Joined: 11 Dec 2012
Posts: 400
Location: WashDC area, ViennaVA


PostLink    Posted: Sat Feb 15, 2014 11:35 pm    Post subject: Reply with quote

P.S. If anyone has any direct messages I could pass onto my pops about such an installation, they would be most appreciated. I know all of you have way more experience with this than us. Thanks Very Happy
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UncleWill



Joined: 11 Dec 2012
Posts: 400
Location: WashDC area, ViennaVA


PostLink    Posted: Sun Feb 16, 2014 12:59 am    Post subject: Reply with quote

P.S.S. What the thread rating is for the bottom holes on the Marquee?
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mr_ro_co



Joined: 08 May 2006
Posts: 1643
Location: Santa Fe NM


PostLink    Posted: Sun Feb 16, 2014 4:44 pm    Post subject: Reply with quote

UncleWill wrote:
Didn't expect this much response Very Happy

I don't know all the proper terminology so will do the best I can to explain. We have wooden joists running from the back to the front of the house that hold up the ground level. Half way in between the entire basement, one steel I beam provides support to all the wooden joists. The house was built in 1983. Will post actual pictures later. My idea was to drill into the wooden joists like in the description here:

http://www.curtpalme.com/MountingMethods.shtm

Anyways, I ran the whole idea of mounting the Electrohome through my dad/landlord. He said no f**king way unless we got a professional to do it. Ugh. So today we went out to a video installer in Virginia. We explained everything and were told that the entire setup would be around $1,200. For the entire job, we could almost get a high end JVC that was just traded in. Coming to this realization, we began smiling and laughing out loud in the store. Then the CRT haters took full swing..

I explained to my dad that it really is not that heavy in comparison to all the furniture up above. Looks like it falling on deaf ears Sad

He wouldn't mind a chain mount on the I beam, but that would take some fancy footwork on my end. Plus it would be hanging a bit lower (enough to hit it with one's head) The projector's path would have to clear a lightbulb and an air vent just to reach the screen.

Any ideas or suggestions?


Even just one 2X8 or 2X12 floor joist will support the Marquee, as long as you securely attached to it at multiple points with either cross bolts through the joist or lag screws threaded directly into it. Even a single 3/8" 6" lag screw properly engaging a quality traditional wood joist (but not an engineered wood i-beam due to modest flange thickness) could easily support the entire weight of the Marquee, at least with a static load. No one would ever do this - it's just for sake of illustration. Given the option, some of us (including you, apparently) would rather use machine bolts that go through the joists crosswise, then connect to those bolts somehow, such as with right angle brackets, or as in your original suggestion, eye bolts/screws that you would then attach chains to. If done right, the cross-through bolt approach is stronger than a lag screw threading directly into the wood joist. It just tends to be more trouble than simply screwing lag bolts directly into the joists.

Regardless of which way the joists are laid out relative to the desired orientation of the projector/screen axis, with typical joist spacing, you should be able to capture at least (2) joists if your layout is inline with them or more if perpendicular to them. Either way, using either through bolt or lag screw, if supported at (4) or more points properly, it will be several times stronger than needed to support the Marquee.

If you use (2) sections of strut as the main support, you can do anything you want after that with a second pair of strut perpendicular to the first pair for full X-Y adjustment capability (recommended). The first pair of strut should be long enough to span (3) joists if oriented perpendicular to the joists. 60" usually gets it. Regardless of the joist orientation, mount each strut to the joist(s) at (3) points, either using through bolts or lag screws. This will give you a total of (6) widely spaced support points into the joists for the first pair of strut, which will be total overkill for your needs. All the hardware you need to mount this projector will cost you less than $100. Of course, if you just use your eyebolt/chain idea directly into the joists, even cheaper, but with less adjustment capability.

A note on lag screws: It's all about the pilot hole. Too small, joist will split, poor load support. Too big, inferior thread engagement, poor load support. Do your homework to determine what the largest lag screw is you can use (both diameter and length), then use the correct bit to drill the correct diameter pilot for the type of material you are screwing into. Very important.

Finally, you keep asking about the load rating of the Marquee mounting threads. I'm assuming you are referring to the (4) 3/8 coarse thread .5" aluminum blocks on the chassis. Without being facetious: A lot. Between the four of them, they were selected with plenty of margin to support the Marquee. They are not an issue.

Best,

Steve

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UncleWill



Joined: 11 Dec 2012
Posts: 400
Location: WashDC area, ViennaVA


PostLink    Posted: Sun Feb 16, 2014 10:09 pm    Post subject: Reply with quote

Quote:
Even just one 2X8 or 2X12 floor joist will support the Marquee, as long as you securely attached to it at multiple points with either cross bolts through the joist or lag screws threaded directly into it. Even a single 3/8" 6" lag screw properly engaging a quality traditional wood joist (but not an engineered wood i-beam due to modest flange thickness) could easily support the entire weight of the Marquee, at least with a static load. No one would ever do this - it's just for sake of illustration. Given the option, some of us (including you, apparently) would rather use machine bolts that go through the joists crosswise, then connect to those bolts somehow, such as with right angle brackets, or as in your original suggestion, eye bolts/screws that you would then attach chains to. If done right, the cross-through bolt approach is stronger than a lag screw threading directly into the wood joist. It just tends to be more trouble than simply screwing lag bolts directly into the joists.

Regardless of which way the joists are laid out relative to the desired orientation of the projector/screen axis, with typical joist spacing, you should be able to capture at least (2) joists if your layout is inline with them or more if perpendicular to them. Either way, using either through bolt or lag screw, if supported at (4) or more points properly, it will be several times stronger than needed to support the Marquee.

If you use (2) sections of strut as the main support, you can do anything you want after that with a second pair of strut perpendicular to the first pair for full X-Y adjustment capability (recommended). The first pair of strut should be long enough to span (3) joists if oriented perpendicular to the joists. 60" usually gets it. Regardless of the joist orientation, mount each strut to the joist(s) at (3) points, either using through bolts or lag screws. This will give you a total of (6) widely spaced support points into the joists for the first pair of strut, which will be total overkill for your needs. All the hardware you need to mount this projector will cost you less than $100. Of course, if you just use your eyebolt/chain idea directly into the joists, even cheaper, but with less adjustment capability.

A note on lag screws: It's all about the pilot hole. Too small, joist will split, poor load support. Too big, inferior thread engagement, poor load support. Do your homework to determine what the largest lag screw is you can use (both diameter and length), then use the correct bit to drill the correct diameter pilot for the type of material you are screwing into. Very important.


A very thorough response. Many thanks. Thumbs Up


Quote:
Finally, you keep asking about the load rating of the Marquee mounting threads. I'm assuming you are referring to the (4) 3/8 coarse thread .5" aluminum blocks on the chassis. Without being facetious: A lot. Between the four of them, they were selected with plenty of margin to support the Marquee. They are not an issue


No, I wasn't worried about them. Just wanted to know what the proper thread size was for when I bought everything Laughing
Clearly they were designed to support the thing so no concern there..
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nettwerkjohn



Joined: 08 Mar 2006
Posts: 887
Location: Nelson, sunshine capital of New Zealand


PostLink    Posted: Mon Feb 17, 2014 11:23 am    Post subject: Reply with quote

a note on chain:i had an ecp4501 straighten out first one, then shear another s-hook whilst it was being lifted. result:kee-rash! tinkle, tinkle, tinkle. no more ecp.
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UncleWill



Joined: 11 Dec 2012
Posts: 400
Location: WashDC area, ViennaVA


PostLink    Posted: Mon Feb 17, 2014 11:09 pm    Post subject: Reply with quote

Yikes! Point on the S-hooks duly noted. Hoping to use quick links on my setup. Most of those are rated from 500-2000lbs.
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