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Eight
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Posted: 12/21/2005 8:23:05 PM
[Last Edit: 12/21/2005 8:23:28 PM by Eight]
I want to anchor my safe to the concrete foundation. I originally bought some lag bolts/anchors for concrete rated at 300 lbs tensile, 450 lbs sheer from Lowes. The hole I drilled for each anchor was 1/2". As I was drilling, I thought the bolts were way too small, especially based on the size of the holes in the bottom of my safe. Anyway, I ended up breaking one of the bolts as I was tightening it. I think it was because I didn't clean the holes out good enough. I could see some of the concrete dust inside the anchor after pounding them in.

The three that remained left the safe wobbly. The safe is on carpet/pad. I cut through the carpet and pad around each hole before I started drilling into the concrete. I didn't try, but it almost felt like I could rip the safe out of the floor if I wanted. I didn't want to tighten the bolts too much as not to break them. Obviuosly that's not the way to set it up to be secure. So I was able to get all the anchors out of the holes along with the broken bolt.

I want to be able to have the safe solid and not have to worry about someone getting leverage and ripping the anchors out of the floor by pulling on the safe. What's the best type of anchor to use for this application? It looks like the kit that is sold (at a huge mark-up) by the makers of my safe includes drop-in anchors with the set tool. If nothing else, I at least plan on getting the biggest size available of the same type I already bought.

Any help is appreciated. Thanks.
Troy
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Posted: 12/21/2005 8:32:21 PM
What size bolts were you using? You want at LEAST 5/16" bolts (will have 1/2" head). These are the largest bolts that you are likely to find that fit readily-available anchors, but I'm sure you can special-order larger ones (Google is your friend).

Standard hardware store bolts are Grade 2, and break pretty easily. They are cheap and do okay for low-stress stuff. Look for some Grade 8 (or at least Grade 5) bolts for this application.

-Troy
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Retched_Rick
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Posted: 12/21/2005 8:39:16 PM
I would use either a stud or all-thread set in epoxy. That shit never pulls out.

We use it in work all the time and structural engineers allow it to be used to correct and set anchor bolts for steel columns that were are screwed up because they were set wrong in the concrete. Check the Hilti website. They probably sell a generic brand at Lowes or the Depot.

I work for a construction company.
ironoxbows
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Posted: 12/21/2005 8:39:26 PM
I think Dzl-Benz is a structural engineer...might wanna IM him
broncobisley1
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Posted: 12/21/2005 8:55:11 PM
[Last Edit: 12/21/2005 9:00:30 PM by broncobisley1]
As you found the lag bolt anchors don't work very well. Home Depot does sell the product you need but I can't think of the name (drop in anchors?). Basically they are steel or aluminum and use bolts not lag bolts. As you tighten the bolt it will bottom out on a plug inside the drop in anchor which flares out the blottom of the anchor (has vertical slots cut in it) into the concrete. It's strength depends on which grade of bolts you use and the stength of the concrete. The only problem with using them is that you have to drill the correct size hole (not a sloppy hole) or the anchor willl want to spin before it starts expanding. Also you have to have the hole drilled out fairly exact depth wise(if not you can buy a bolt to long and use a hacksaw to cut it to the correct length). They come in many sizes.
angry_walkin_dude
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Posted: 12/21/2005 9:12:50 PM

Originally Posted By Retched_Rick:
I would use either a stud or all-thread set in epoxy. That shit never pulls out.

We use it in work all the time and structural engineers allow it to be used to correct and set anchor bolts for steel columns that were are screwed up because they were set wrong in the concrete. Check the Hilti website. They probably sell a generic brand at Lowes or the Depot.

I work for a construction company.



+1 They make a kit, but I can't remember the brand.

Air Liquide uses these to anchor most of there large tanks such as liquid oxygen or argon.
Cougar8045
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Posted: 12/21/2005 9:28:45 PM

Originally Posted By broncobisley1:
As you found the lag bolt anchors don't work very well. Home Depot does sell the product you need but I can't think of the name (drop in anchors?).



Wedge anchors

I've bolted down many many houses with them. 1/2"x4" or 1/2"x5" should do the trick. They're easy to put in and if someone wants to steal your safe, they're going to have to take the concrete slab with them.
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snarfbatt
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Posted: 12/21/2005 10:38:49 PM
Check with the Hiti company , they have an anchor system that has epoxy and anchors. I am sorry I don't rememeber the hilti number but it uses 3/8 or 1/2 inch hardened rods and anchors. If they wrap a chain around the safe they will break the safe before the anchors.
Specop_007
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Posted: 12/21/2005 10:40:59 PM

Originally Posted By Troy:
What size bolts were you using? You want at LEAST 5/16" bolts (will have 1/2" head). These are the largest bolts that you are likely to find that fit readily-available anchors, but I'm sure you can special-order larger ones (Google is your friend).

Standard hardware store bolts are Grade 2, and break pretty easily. They are cheap and do okay for low-stress stuff. Look for some Grade 8 (or at least Grade 5) bolts for this application.

-Troy



Grade 8 bolts are the shizznizzle.
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Troy
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Posted: 12/21/2005 10:53:48 PM

Originally Posted By Specop_007:
Grade 8 bolts are the shizznizzle.



I've been accused of "overengineering" things more than once. For example, it was recommended to me that I use four 1/4" bolts to secure the camper shell to my truck's bed. I ended up using EIGHT 5/16" bolts, Grade 5 to be exact. If I could have gotten some Grade 8's easily, that's what I'd have used.

I *hate* to do a job TWICE.

-Troy
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zoom
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Posted: 12/21/2005 11:29:40 PM

450 lbs sheer from Lowes...I ended up breaking one of the bolts as I was tightening it.

About 20 years ago 20/20 did a story where they claimed the Chinese were trying to destroy the US economy by shipping inferior fasteners that were sold in US chains like Lowe's and Wal-Mart. They gave examples of buildings, bridges, and several mechanical items including lawn mowers and cars that had killed people due to screws and bolts that had failed when they shouldn't. The more bolts I break and the more screws I strip from Lowe's and Home Depot, the more I believe them. I don't understand how they get away with claiming something is a certain strength when it isn't. The last grade 5 1/2" bolts I bought from Lowe's broke with about 100 ft-lbs of torque on the wrench. I broke one by accident then intentionally broke a couple more just because I couldn't believe they were such junk. I bought replacement ones from NAPA, and I could not break them even when I tried even though both sets were grade 5. With the rated strength you quoted, you shouldn't have been able to break them.

In this age of law suits, I don't understand why Lowe's and Home Depot haven't been punished for this.z
thebeekeeper1
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Posted: 12/21/2005 11:36:09 PM
I wouldn't put carpet under it--perhaps heavy visqueen if moisture is a problem. I would use "Hilti bolts"--aka wedge anchors, as mentioned above--in 1/2"X4" (depending on depth of concrete pad).

Use a hammer drill to drill a 1/2" hole--clean it out with air--pound that bad boy in, then put a big washer on it, then tighten it down good. Four of them, near each corner, will hold it adequately. They will NOT pull out. If possible, find the Hilti brand, but the generic "Red Head" brand will suffice.
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krpind
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Posted: 12/21/2005 11:42:23 PM

Originally Posted By zoom:

450 lbs sheer from Lowes...I ended up breaking one of the bolts as I was tightening it.

About 20 years ago 20/20 did a story where they claimed the Chinese were trying to destroy the US economy by shipping inferior fasteners that were sold in US chains like Lowe's and Wal-Mart. They gave examples of buildings, bridges, and several mechanical items including lawn mowers and cars that had killed people due to screws and bolts that had failed when they shouldn't. The more bolts I break and the more screws I strip from Lowe's and Home Depot, the more I believe them. I don't understand how they get away with claiming something is a certain strength when it isn't. The last grade 5 1/2" bolts I bought from Lowe's broke with about 100 ft-lbs of torque on the wrench. I broke one by accident then intentionally broke a couple more just because I couldn't believe they were such junk. I bought replacement ones from NAPA, and I could not break them even when I tried even though both sets were grade 5. With the rated strength you quoted, you shouldn't have been able to break them.

In this age of law suits, I don't understand why Lowe's and Home Depot haven't been punished for this.z



In my experience the harder the bolt, the easier it is to break by over torqueing it.

Now shearing it is another story all together.
EricTheHun
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Posted: 12/21/2005 11:45:13 PM
I wouldn't ask Scott Peterson this question.

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Posted: 12/21/2005 11:47:38 PM

Originally Posted By Retched_Rick:
I would use either a stud or all-thread set in epoxy. That shit never pulls out.

We use it in work all the time and structural engineers allow it to be used to correct and set anchor bolts for steel columns that were are screwed up because they were set wrong in the concrete. Check the Hilti website. They probably sell a generic brand at Lowes or the Depot.

I work for a construction company.



I use "Hilti's" everyday, can't beat them.

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krpind
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Posted: 12/21/2005 11:50:17 PM

Originally Posted By EricTheHun:
I wouldn't ask Scott Peterson this question.

Eric The(TrueCrimes)Hun



I should not find that funny......but DAMN it is!
sandboxmedic
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Posted: 12/21/2005 11:51:49 PM
If you use the epoxy, be sure to blow the dust out of the hole well in order for it to set up properly.
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Eight
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Posted: 12/22/2005 7:45:35 AM
Thanks for all the suggestions. I was using lag bolts that were 5/16". Whatever grade they were, I don't want them holding my safe down.

My safe is on the carpet just because that's what's on the floor. I'm pretty sure my wife doesn't want me cutting all the carpet up off the floor around the safe. While I agree that it would be more sturdy, it's not an option for me.

What exactly am I looking for on the Hilti website? They have too much stuff. I did a search for wedge anchor and came up with 5 pages of results. They all look the same, though. Any place to buy other than their website? I guess I could call them for a price, since they don't list any.
BillLumberg
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Posted: 12/22/2005 7:56:15 AM
I'd use an epoxy based anchor. Hilti makes them and should be available at a home depot or similiar type store. Basically the same thing where you drill your hole. infuse it with the epoxy set your bolt let it dry (dries pretty quick) set your safe and crank down the nuts. We use them all the time for setting floor systems off ledger boards.
Helldog40
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Posted: 12/22/2005 8:01:08 AM
Hilti "Drop Ins" in the appropriate size or use Rawl "Chem Studs" to set threaded rods in...this stuff is expensive but easy to use. I've put three story columns up with it plenty of times when the installed anchors were wrong...
Cleatus
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Posted: 12/22/2005 8:17:57 AM
[Last Edit: 12/22/2005 8:19:51 AM by Cleatus]
lag bolts are teh suxxor I was just using them for putting shelves up in the garage and I cant remember how many snapped off when i was using my drill to install them (pre-drilled holes too!!!) I could not believe how little torque it took to snap them

IF you use lags- use the heaviest size you can reasonalbly use- I am not a expert on the concrete fastners so some of the above would prob work great.

Alos if i recall- a few year back I think they passed some sort of "fastner accountibility act" or some damn thing- all fasteners must be traceabl back to the company with head staps or something- will maybe look it up if i can- bu i though i heard of something like this- maybe modern fastners are stonger/more reliable.


found it:
FQA fastner quality act
wildearp
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Posted: 12/22/2005 8:24:00 AM
Homey Depot sells "Redheads" I have used these a lot. They are wedge type expansion bolts and are high quality. 1/2" or larger!!!!
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Eight
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Posted: 12/22/2005 8:32:16 AM
Okay, one thing I didn't think of was ease of install. Something with a separate anchor and bolt would be preferable.

After looking at the wedge anchors, it looks like they would have to be installed, and then the safe set in place. I'm not sure how I would be able to lift the safe and drop it down exactly in the right place on the rods sticking up out of the concrete. With a 2 piece system, I can slide the safe into place and view the anchors from the holes in the safe, slightly adjusting it until all the holes line up. Then drop the bolts in.

I don't have any experience with the epoxy anchors. Maybe after the holes are drilled, I could fill them with the epoxy, slide the safe into place, then drop the threaded rods down in from the top and wait for them to dry. Only problem is if I ever needed to move it, I'd run into the same problem as with the wedge anchors.
fizassist
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Posted: 12/22/2005 8:37:37 AM
Tag for good info. I'm moving into my first house, and I'm finally going to get the safe bolted down. Thanks, guys!
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Kharn
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Posted: 12/22/2005 8:48:14 AM
[Last Edit: 12/22/2005 8:52:11 AM by Kharn]
Tip #1: Measure the depth of the concrete after drilling when you buy the Red Heads, you want the anchor SHORTER than the depth of the concrete, as you lose strength if the anchor pokes out the bottom of the concrete. Or just buy ~3.5" long ones, most concrete slabs are 4" thick.

Tip #2: There are no "test runs" with Red Heads to check for depth, once you start it in the hole, you can only push it further in, you cant pull it out. Mark your drill bit for the depth you must drill.

Tip #3: Buy the largest diameter ones you can, measure the holes in the bottom of your safe and get the biggest size that will fit.

Kharn
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Posted: 12/22/2005 8:53:04 AM
I just used 4 - 1/4" Tapcons. You don't need that much. Damn if i could put the thing over.
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SPTiger
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Posted: 12/22/2005 8:56:51 AM

Originally Posted By wildearp:
Homey Depot sells "Redheads" I have used these a lot. They are wedge type expansion bolts and are high quality. 1/2" or larger!!!!



I'm glad someone else mentioned Redheads, I was beginning to think I had made it up. I used them to hold an outboard motor mount to the wall that I built. At work we keep out outboard motor inside when no in use so I had to find somewhere to put it.

I would bet that MSC or McMaster-Carr would have a good selection of anchors to choose from.
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