HOW TO: bolt safe to floor


February 13, 2008, 04:30 PM
how deep do the holes need to be drilled? can someone point me to a how to or provide a simple description of correctly securing a small safe?

If you enjoyed reading about "HOW TO: bolt safe to floor" here in archive, you'll LOVE our community. Come join today for the full version!
February 13, 2008, 04:32 PM
Are you drilling into concrete?

We usually drill about 3/4" lower than the anchor length.

February 13, 2008, 04:40 PM
its into concrete. do you drill the same diameter as the anchors or a size smaller? how deep should i go as a minimum(dont have anchors yet)? im concerned about pipes and what ever else might be in the foundation.

February 13, 2008, 06:32 PM
It may vary where you are at, but around here, there's never any pipes or wiring in the floor (unless it's a heated floor). It's also very rare to have anything encased in a foundation wall.

We use mostly 3/8" and 1/2" wedge anchors at least 2.75" in length. You drill the hole using the same size bit, and drive the anchor in with a hammer. After it's driven in, you tighten the nut(s) and you're done.

If you're bolting a gun safe, you can usually drill the holes from inside the safe without having to move it back and forth. If you're bolting a smaller safe, you will probably have to place the safe, mark the hole, move the safe, drill the holes, and then move the safe back into place.

February 13, 2008, 06:36 PM
I went through the same concerns last year. I ended up just going for it. I broke a cheap, generic hammer drill in about 20 seconds, without so much as a dent to show for it. After buying a big name hammer drill (thing must weigh 20 pounds), I got two 1/2" holes approx 3-4" deep in a half hour, or so. I kept a cup of water nearby to cool the bit down, every so often. IIFRC, the labelled diameter of the masonry drill bit you use will be the same as that of the security bolts. I clearly recall a huge PITA of getting the bolts to line up correctly. It's rather impossible to drill a hole perfectly str8 into concrete, unless there's a trick I don't know about. It must of taken me 3 or 4 hours to get the thing installed, in all.

I think it would be pretty bad luck to hit a conduit if you are drilling only a few inches, but I really don't know. Maybe I got really lucky.

February 13, 2008, 06:55 PM
Just skip the holes... secure it with a boogeytrap instead ;-) you get those things that looks like a firealarm, filled with pepper and CS gas. they react to movements. it makes it impossible to stay in the room.

February 13, 2008, 07:15 PM
I've ruined plenty of hammer drills/rotary hammers. Try this. Forget the consumer level hammer drills. I bought a Hilti (brand), that drilled literally hundreds of holes up to 3/4" in all types and ages of concrete and rock. They are expensive. I recommend that unless you think you'll be making a LOT of holes, go to your local tool rental place (you know, the place that rents rolling hydraulic lifts, motorized sewer cleaners, jack-hammers, etc.) and rent one for an hour or two. Buy the Hilti brand fasteners, they're a couple bucks apiece, and are worth 10 times the price. You'll pull the bottom out of your safe (or pull up large pieces of concrete) before they pull out of the floor; and forget shoving the safe along the floor to shear the bolts, their shear strength per 1/2" bolt is somewhere around 90,000 lbs each. The Hilti (even the smaller models) will drive a 1/2" hole about 3"/minute... mostly let the drill do the work; you don't need but a pound or two pressure on the handle.
I don't work for Hilti or any other tool company. But I did many types of carpentry for 18+ years, and learned what works well, and what isn't worth crap.
Best regards,

February 13, 2008, 07:19 PM
One more thing, to keep the bit from walking around/wandering when you're starting the hole (not much problem with the Hilti), first drill through a 2x4 about 18" long. Slide the 2x4 up to the chuck and place the bit where you want it, then slide the 2x4 down to the floor. Stand on the 2x4, and start drilling.

February 14, 2008, 12:13 AM
I work for a General Contractor, and the bulk of my trade experience is in concrete. I have also worked as a code inspector.

My advice is to rent a good-quality hammer drill from Home Depot or Lowes (if the one in your area rents) along with a drill bit and epoxy-set anchor bolts (from Fastenal). Epoxy set anchor bolts allow you to oversize the hole and still get a secure hold (they are the most error-proof system). I would then set the safe, and mark the drill holes with a sharpie on the concrete. Then pull the safe off the concrete and drill the holes. The slab-on-grade in most houses is almost never over 4 inches, and frequently less due to shoddy construction. If you drill all the way through the slab, it will actually make for an inferior anchor connection, and your adhesive will drain away into the stone drainage area beneath. If this does happen, fill the hole with cheap painter's caulk and proceed, hoping you'll still get a decent connection.

using the biggest diameter anchor you can find that will fit in the safe hole
(1/2" or 5/8" should be fine) drill the hole 1/8" in diameter greater. In other words, if you are using a 1/2" anchor bolt, use a 5/8" drill bit. drill into the slab about 3", or more ONLY if you are confident the concrete is thicker.

MAKE SURE the hammer drill is on the "hammer drill" setting. It will probably be a little icon of a hammer, with sloped lines on it. If there are no sloped lines on the hammer, it is probably the "chipping hammer" setting. wrong. If there are just sloped lines on the icon, it is the "drill" setting, which may be what you were using if you drilled for an eternity with no progress.

As you drill the hole, drill a short distance and while the drill is running, push it in and out of the hole to remove concrete dust while drilling. this should be a familiar motion. when you are done drilling, blow the hole out with a compressor or vacuum it with a shop vac. don't blow into the hole with your mouth, you will get a faceful of dust and your eyes will hurt like heck from the lime in the concrete (no experience here!).

Then put the safe in place. Using a caulk gun, fill the hole 1/3 of the way with anchor adhesive (should be available where you bought the bolts, Fastenal is a good supplier if they are in your area). then stick the bolt in the hole, and hold it there for 30 seconds to allow it to seat. Otherwise it will push back out. Wipe up the residue and wait one day to install the washers and nuts. Crank on the nuts about 1/2 turn past snug, no need to kill them. If you crank on ANY anchor bolts too much, it will grind out the concrete and you'll have no anchor connection of any value.

February 14, 2008, 12:19 AM
- Rent a hammer drill
- Buy some bits for concrete
- Drill holes
- Clean the dust and crap out of the holes
- Tap anchors into holes
- Bolt down safe

February 14, 2008, 08:46 AM
I called a Locksmith. He came with all of the proper toold and equipment. Moved the save to the ideal position. Drilled and anchored the safe with anchor bolts and cleaned up his mess. Took about 45 minutes and cost $85.00. Couldn't have done it that cheap myself.

February 19, 2008, 09:15 PM
My refurbished Dewalt SDS Hammerdrill will put a 1/2" hole 6" deep in hard concrete faster than you can drill through a 2x4 with a good wood bit. Be sure to use stainless anchor bolts. I'd drill the holes as deep as possible, in case you ever want to move it, you can knock the bolts further down in the holes and plug 'em - they ain't coming out the top. Some say don't drill all the way through the slab (if you have that much bit), but I would if I could, and just waterproof the hole first. That way you can knock the bolt all the way out and put another behind it if you ever need to.

February 19, 2008, 10:14 PM
I used 3/8" wedge anchors, although drop in anchors are good too. Make sure to torque to the right amount and no more! I can't believe that it took 30 minutes to drill a couple holes with a hilti. It took less than 10 including setup to do the same with a rotary hammer I borrowed from a guy at work.

March 20, 2010, 11:12 PM
I have a Bosch Model 11210.7 hammer-drill that must be twenty years old, and I've drilled hundreds, if not thousands, of holes with it in standard 4000# psi concrete pads, using carbide-tipped bits, anchoring machines, pallet racks, (and a safe or two) with various styles of wedge-anchors, usually Thunderstuds. I'm posting only to counter-balance those posts that opine that hammer-drills are inherently prone to failure. Not mine. I'm guessing it cost me $400 or so, way back when. Surely you know someone you could borrow a decent hammer-drill from (?).


If you enjoyed reading about "HOW TO: bolt safe to floor" here in archive, you'll LOVE our community. Come join today for the full version!