Attaching steel or wood to concrete is rarely as simple as it ought to be. There are all sorts of fasteners available for the job—lead shield anchors, expanding bolts, wedge bolts, drive-pin anchors, and drop-in anchors, to name a few. What most of these fasteners have in common is that they can be unpredictable and unreliable when it matters most. Fasteners that don’t work as planned cost both time and money.
I’ve just come across a great concrete fastener called a Large Diameter Tapcon anchor, or LDT, from ITW’s Red Head brand. No special bits or sockets are required—I use a hammer drill/driver with standard masonry bits and sockets. The bolt actually cuts threads into the concrete, and you can thread them in and out several times without affecting their holding power. That makes it easy to shim or make other adjustments. For best results, be careful to engage the threads when reinserting the anchor, just as you would with any machine bolt.
I mostly use 3/8-inch anchors, but ½-, 5/8-, and ¾-inch LDTs are also available. Another nice feature is that these anchors have a textured finish that will accept a powder coating to match the finish on whatever you’re fastening. But the best thing about them is that it’s drill, drive, done.
Matt Jackson, aka, the Timber Tailor, is a master carpenter, remodeler, and Sketchup pro in Rapid City, S.D.