This thread has been bothering me so much that i went out to the job i just finished and removed 2 of the 4 lag bolts i used just for spite. It still wont fall down.

Which two?

On on each side to keep things fair and balanced

Nice one!

ROTFLMAO!!!

I normally use these...At 60lbs capacity each, 2 are more than adequate for any modern LCD through 65":

[Link: walmart.com]

Kind of makes you think doesn't it. We argue about lags in plywood not being strong enough to hold a TV. I have worked in homes with artwork that costs 100 times what a TV does and have frames that probably weigh and must as a TV and this is what they are hung from in only drywall.

Ok, articulating mounts do not apply.

Working at a job a couple days ago, the interior designer was trying to hang a mirror on the wall that took two people to lift. She put two screws into the sheet rock. I looked at the homeowner and shook my head.

I think it's notable that there's an Engineering class called Strength of Materials. the title alone tells us that we don't understand what it takes to make things, and what's too strong or too weak.

For the unschooled, at one end, we have the mirrors hung as you described them. At the other end, again for the unschooled, we have the average ten-year-old boy's wood project which I once heard described as "likely to assay more than 60% steel, all in the form of nails."

Most of us appreciate that things must be strong but don't know it if we overbuild them. We certainly are not capable of designing them to be only as large and strong as absolutely necessary to get the job done. We tend to overbuild without really knowing we're doing it.

We're just looking at the other end of the scale of the folks who haven't taken that class.

Fixed it for ya.

When I took that class, it was called 'Statics and Strength of Materials', but was geared toward architectural engineers, not installers.

I worked for a dealer of home and car audio- one of the kids was in college for engineering and one of their assignments was to build a tower using a specific number of wooden toothpicks and Elmer's Glue- when they were done, they were to be tested for their weight-bearing ability. I asked a structural engineer for some ideas and he reminded me that a cylinder is an inherently strong form, so I relayed the information. Unfortunately, when the last toothpicks at the top were glued in place, he left the ends sticking up and that's what caused its failure. If he had clipped them, I think it would have held double and for the purposes of the class, ANY component failure was as good as total collapse. His held 180 lb.


On a related note, the Snap Togglers are great, if you can keep the plastic from breaking with minimal upward pressure. I broke several today, trying to install a projector mount and I wasn't using a powered driver. Pissed me off! The toggle fit through the holes easily, the ends were even when I clipped them and still, the stupid POS would break.


Better to over-build than have it fall on someone.

A friend who was an architect called them 'Interior Detonators'.

With all this discussion on what to use to anchor the TV, no one has addressed the statement of "plywood"! Who said it was plywood and how thick is it. 1" thick plywood is very rare, before I believe that it is 1 inch thick, I would want to confirm with a test. Also, what type of plywood is it, many people call all wood panels plywood. If it is in a cabinet, I would assume that it has a veneer covering to match the rest of the cabinet, BUT WHAT IS THE VENEER BONDED TO? It could be MDF, particle board, a weak low grade aisian plywood, or one would hope for fir veneer core plywood that is very strong.

Question the source of information regarding the material, get permission to drill a hole to check the thickness and the core materials. You may find that it is questionable in regard to its ability to hold the TV and that the cabinet will need to be pulled out and reinforced by the original builder or another cabinet maker before risking your reputation.

Post 1. Assuming "Ply" = Plywood


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This is why we installers generally don't know how strong things are and we overdo it... or we mess up and make things barely strong enough to be safe.



Used wrong tool. Didn't work. STUPID tool!


When I drill these -- with a POWER TOOL -- I deburr the front and back of the hole, and only one in twenty or so doesn't go in correctly.


Yes.


OP said it was plywood, we think, but this is A GREAT AND CRUCIAL POINT because he did not say it was plywood, he said it was ply wood.


OP, that's who. We can't question EVERYTHING about the description that the original poster gives, though I question everything that seems wrong or unclear!


He said it was 3/4" or 1."

Continued good questions. We very often need to back up from the question that is asked so we can verify why the question is asked. More than once we've been asked how to implement a squirrely solution based on a misunderstanding of the situation.


I just mounted a 65" Sony on tile above a fireplace; this tile was mounted over thin flagstone. This was successful because we opened the flagstone, built in several pieces of 2x wood, then faced the whole area off with plywood (really, plywood, in this case 3/4" + 1/2") flush with the flagstone; the contractor understood that his tile could not be mounted with ANY voids in the grout or cement or whatever.

Before hanging the TV, we pulled the mount out 24" and one of us hung on it.

Be sure you know what your material is and reinforce the holy living crap out of it.