Son of a... Two different lag bolts broke during wall mount install

[DisgruntledVirus]

Picked up a Sanus VMDD26B wall mount for my Kuro 5080 so I could use it again (my ex had it and was using it because I didn't have place for it in my new apt unless I wall mounted). This thing is one heavy thing. I have no question that it will hold the tv. However from the start I was questioning the lag bolts. They seemed questionable, especially after seeing others saying they snapped on them. Decided to use them anyways. First one snapped almost all the way in. Managed to get the bolt out, and started agin with 3 bolts (and pickup a 4th after work today). Well another one busted. Ugh...

So anybody else have lag bolts break during install?

 

[MagnusTheBrewer]

How are you installing the lag bolts and what tool are you using?

 

[DisgruntledVirus]

Following the manual. Using a 3/16 bit to drill a pilot hole into the studs. Then using a ratchet on the hex heads to tighten. They weren't even all the way to the wall plate when they broke so it wasn't from tightening them too much.

 

[NutBucket]

Did you drill deep enough?

 

[DisgruntledVirus]

Did you drill deep enough?

Drilled as deep as the lag bolt was in length.

 

[TwiceOver]

Ignore what the instructions say. Something tells me your pilot holes are too small. I usually go slightly smaller than the shaft of the lag bolt.

EDIT: Or the bolts themselves suck.

 

[Matt1970]

I am thinking the lag bolts suck.

 

[Howard]

Uh, the bolts broke as you tightened them into the studs? And they weren't even all the way in?

What were these made of, foamy cast aluminum? Go to the hardware store and get some Grade 5/8 and set yourself straight.

 

[Doppel]

My money is on the lag bolts sucking. Lag bolts are thick hard metal, if you were breaking the actual head off the bolt you'd be having to put enough torque through that anybody would wonder what's going on. And as the head is the weakest point on a fastener when putting it in if anything else broke it's even worse.

FWIW I doubt it was incorrect pilot hole, but a pilot hole should be approximately the width of the interior diameter of the screw so that the threads of the screw alone are displacing wood. If I can't get one that exact size I typically err by making it very slightly smaller to snug nicely around the rest of the shaft. Ugh, don't read the second half of that sentence again.

 

[CubanlB]

Lag bolts that come with cheap mounts (or really any mounts) can be pretty sucky. But they shouldn't be snapping like that. Did if feel like you hit a knot in the stud while predrilling? lag bolts compress the wood in the stud where they are installed quite a bit and knots just wreck them.

That being said, as an AV installer for almost 4 years, we basically never used the bolts that cam with the mounts. 1/2" drive head lag bolts ftw.

Also, I have snapped quite a few lab bolts off but it can happen for a variety of reasons, but usually it has more to do with using a drill and not quite the right size socket, or not being lined up on the bolt properly.

If the TV is up you should be fine, but if you're concerned, some store bought bolts are cheap peace of mind.

 

[Exterous]

+1 for avoiding the bolts/screws that come with the kits. I have seen too many cheap screws/bolts that just aren't worth the time and hassel to deal with - especially with projector mounts. I generally have a pretty good selection of fasteners available and I just match up the sizes

 

[DisgruntledVirus]

It is a Sanus mount, which I trust the company and the mount. However these lags were shit. The two bolts that broke were in two different studs, so I find it hard to imagine that *both* studs had knots at the exact spot I placed the lags.

Neither Lowes nor Home Depot sell grade 5/8 lags. I will most likely order some online. Unfortunately the wall mount won't happen now at my current place due to other circumstances. So wall mount will basically be stored until I move again and can install this. I'll be getting some grade 8 lags that are 3/8 diameter and 3-3.5 inches long though for when I finally get to mount this.

 

[CubanlB]

It is a Sanus mount, which I trust the company and the mount. However these lags were shit. The two bolts that broke were in two different studs, so I find it hard to imagine that *both* studs had knots at the exact spot I placed the lags.

Neither Lowes nor Home Depot sell grade 5/8 lags. I will most likely order some online. Unfortunately the wall mount won't happen now at my current place due to other circumstances. So wall mount will basically be stored until I move again and can install this. I'll be getting some grade 8 lags that are 3/8 diameter and 3-3.5 inches long though for when I finally get to mount this.

Sanus makes great mounts and I was disappointed when my previous employer decided to drop them and go strictly omnimount. (which was idiotic because at the time that meant that we had no mount that would fit a 65" Panasonic Plasma)

I totally agree that the knot thing was reaching, but it can be an issue. The bulk lag bolts at homedepot or lowes should be fine, and much higher quality than anything that is coming with a mount.

Good luck getting it put up in the future.

 

[kornphlake]

You can lubricate the threads of a lag bolt with a bar of soap, it will make it a bit easier to turn the bolt without breaking off the head.

 

[Binky]

Crappy Chinese drywall, now crappy Chinese lag bolts!

 

[Doppel]

Neither Lowes nor Home Depot sell grade 5/8 lags.

Did you check the external hardware--the galvanized bolts? The strength on any of those regardless of grade should be magnitudes more than it needs to be to support a flat screen on a mount.

 

[Modelworks]

That isn't surprising,you can tell the grade of a bolt by looking on the head. For US sizes you want a bolt with 6 diagonal lines, if it doesn't have any at all it is the lowest grade. Any hardware store should have those bolts in stock as they are used on everything from lawn mowers to playground equipment. Also get coarse threads not fine threads for wood work.

If your hardware store doesn't have them then go to an auto parts store , they will have some .

A grade 6 bolt shouldn't break off when hitting a knot, piece of steel or concrete. You are likely to break the socket before the bolt.

 

[kornphlake]

Lag bolts most likely aren't graded since they are typically threaded into wood studs. Graded hardware typically has machine threads.

 

[vi edit]

Soap + socket hooked up to an impact driver. Should bury it like a knife through hot butter.

 

[DisgruntledVirus]

Did you check the external hardware--the galvanized bolts? The strength on any of those regardless of grade should be magnitudes more than it needs to be to support a flat screen on a mount.

There were galvanized lags at one of the stores, but I forget which one. Regardless I'm going to be taking the lags I picked up back and ordering some grade 8 lags online. Anybody know where to go for that?

That isn't surprising,you can tell the grade of a bolt by looking on the head. For US sizes you want a bolt with 6 diagonal lines, if it doesn't have any at all it is the lowest grade. Any hardware store should have those bolts in stock as they are used on everything from lawn mowers to playground equipment. Also get coarse threads not fine threads for wood work.

If your hardware store doesn't have them then go to an auto parts store , they will have some .

A grade 6 bolt shouldn't break off when hitting a knot, piece of steel or concrete. You are likely to break the socket before the bolt.

I will check the included lags when I get home. Lags that had fine machine heads were all over, but coarse threaded ones for the wood use are *not* easy to find in anything better than just stainless steel at Lowes/HD. As I said, one did have galvanized at least.

Soap + socket hooked up to an impact driver. Should bury it like a knife through hot butter.

Don't have impact driver unfortunately. I will keep the soap idea in mind though.

 

[Modelworks]

I will check the included lags when I get home. Lags that had fine machine heads were all over, but coarse threaded ones for the wood use are *not* easy to find in anything better than just stainless steel at Lowes/HD. As I said, one did have galvanized at least.

If you can't find coarse threads you could drill out the holes and use lag shields installed in the holes, then use fine thread bolts inside the shield.Lag shields expand when you insert the bolt, normally used for concrete but I have seen them used on wood too, it virtually creates a nut inside the wood for the bolt. If you ever need to remove the screws and put them back in you will not weaken the holding strength. With wood screws you lose holding power when you remove and re-use the same hole.

 

[ericlp]

go to home depot or lowes they have the lag bolt you are looking for and you won't even need to drill a pilot hole tho, I would just so you don't split the wood.

Sometimes I'll just use a deck screw as a pilot hole, sink it in, then back it out. No need to drill. I'd never trust cheap lag bolts esp if one snapped. Never had a lag bolt ever snap on me from lowes.

 

[QuantumPion]

I had a lag bolt break when I was installing a mount for my projector screen too! Luckily the head broke off when the bolt was mostly in so I just left it as is. No idea how I'd ever remove that thing when I sell the house though, lol.

 

[DisgruntledVirus]

I had a lag bolt break when I was installing a mount for my projector screen too! Luckily the head broke off when the bolt was mostly in so I just left it as is. No idea how I'd ever remove that thing when I sell the house though, lol.

We used vice grips. It marred up the wall (it was so close to it), so it might take some touch up work after... but wasn't too hard to remove them

 

[roguerower]

I just hung my Kuro Pro101FD on a Monoprice mount, no issues what-so-ever. Lag bolts all went in with an adjustable wrench (cant find my socket set).