Accurate Holes in Concrete? (Slightly Bogus Metal Content)

did this a month ago in my garage in the concrete block wall. used a nail to put an indent in the wall then drilled, mounted and reused the nails in the other holes for a spot for the drills worked fine

It helps to turn the hammer function OFF to start the hole. This keeps the bit from traveling so much. A steel template to guide the bit would also help. That's a bit of extra work but "it takes what it takes" to get it done right.

-- Gary Brady Austin, TX

Starting with a small bit - *and light pressure* should get you the accuracy you need. Lots of people really lay into the drill when using a hammer drill - and it's not necessary. If these brackets are pretty much going to be permanent - you could always use a "bang stick" and anchor them to the wall - just not easy to remove if you have to. Ken.

Use a small rotohammer instead of a hammer drill. I had a Milwaukee, and it was so sweet. There is something about the percussion that is different than a hammer drill. You don't have to get a big monster that is hard to hold up there vertical. They are made in smaller sizes. It might help to drill a small diameter pilot hole, too. A rotohammer is as much better than a hammer drill as is a hammer drill is to a regular drill.

Steve

PS: I would use sleeve anchors rather than the plastic thinguses. Drill your holes deep enough so if you want to abandon the bracket, you can pound them in and put some concrete patch in the hole.

Steve

Steve

Use a 3/16 drill as a pilot bit. Then go to full sized.

And use metal expanding anchors. The plastic ones will pull out over time. Often, in a very short time.

Gunner

"In my humble opinion, the petty carping levied against Bush by the Democrats proves again, it is better to have your eye plucked out by an eagle than to be nibbled to death by ducks." - Norman Liebmann

An awkward pain every time I piddle with this stuff too... same deal getting clean holes in plaster, stucco tile and brick too.

Miserable materials to work with in my book...

Erik

*Please* tell me you are going to hang the ladder using the metal hooks and plastic expansion anchors for storage, and not for structural support while climbing the ladder...

(For climbing support, you need something seriously beefy and reasonably bombproof like 1/2" expansion bolts or sleeve anchors of some sort. 1/4" plastic sleeves and #10x1" screws won't cut it.)

1/8" carbide pilot bit carefully drilled in to start the hole as close to the desired center as you can get it, and then a single pass to your finished hole size. No matter WHAT you do the bit will want to wander with the aggregate - and it's really going to wander badly if they used quartz gravel that's harder than heck, so plan on making one or two holes in the bracket a bit oversized or oval to accommodate. Or punch a new hole if it moved a mile.

If you are ever making a big roof access ladder or other big steel structure, don't weld the mounting tabs permanently until after all the anchor holes for the mounting are drilled - if the hole wants to wander while drilling you don't fight it, you simply modify the bolt tab location to match where the anchor ended up...

"Don't raise the drawbridge, Lower the river." ;-)

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My trick with stuff like this is to just drill big and fill the hole with epoxy to fix the oversized hole and get the fitting where I really want it to be. The cheap and dirty is to drill the holes in the part to be mounted later.

-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works every time it is tried!

I made a center punch by welding a blob of #6 Stellite ont the end of a piece of rebar and machining (carbite cutter) an appropriately shaped point. I've center punched quite a number of starters in concrete with this. For just three holes, a piece of drill rod hardened and tempered should do.

Those plastic thingies are junk. Epoxy a piece of threaded rod into slightly oversize holes (e.g. 9/16" hole for 1/2" threaded rod). This is far stronger (and cheaper) than expansion fittings.

Ted

A couple folks have mentioned using metal anchors. I'm familiar with the lead expansion anchors, and Rawl plugs (?), which will take a bolt, but also require a specific depth hole. I also have used concrete screws, but because my holes usually end up oversized, they never seem to hold very well.

The weight of the ladder will mostly be perpendicular to the fasteners, so as long as they don't vibrate loose, there isn't a lot of force being applied that would pull them out.

Doug White

If it really really concrete, use Powers brand Wedge Bolts:

These require a special high tolerance drill bit for the lead hole and suggest an impact gun for installation. Excellent anchor.

Pull out values here:

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