Torx Lag Screws

Whoever came up with the idea for these things deserves some kind of “Hardware Award”.  Maybe even a Nobel Prize.  Serious.

For years and years, when building decks and other construction assemblies, it was not uncommon to have to use lag bolts to hold one thing to another.  Lags did the job fine for then, but now with these Torx Lags, the job has gotten much easier, faster, and in many ways, better.

When you used to have to use a lag bolt, a hole was often predrilled, the lag inserted and set with a hammer, and then finished off with a box wrench, socket wrench, or an impact driver.  It was hard to do in tighter spaces and after 20 of these connections, your arms and shoulders were letting you know exactly how much fun it was to build today.

I came across these in 2006 and tried a bunch on a job where we had to attach a second story deck ledger to the outside wall of a house.   The ledger was 32 feet long, and required a fastener every 16 inches.    The Torx lags were used and we had the ledger installed in less than 15 minutes!  With the lags, it would have been at least twice that if not more.  Plus, I feel we did a better job since they were installed with such little effort that we actually used more of them than was required.  And, because of the self drilling tip on the screw, the wood splits less if at all.

To explain the screw a bit, there is a #30 Torx driver tip that I use in my 18 volt DeWalt cordless impact driver to run the screws in.  This tool is great for these as it is lightweight and easily handles with one hand.  With traditional lag screws, I had to use a ½” electric drill with a stabilizer handle, the associated extension cords, and both hands.

The screws are plated for outdoor use, and also have a self cutting tip with engineered teeth in the screw ridges to make long cuts into solid wood with minimal effort.  I have run 10” and 12” versions of these screws into solid beams with no more effort than a one handed impact driver requires.  Very easy to use.

It is also interesting to be able to use these for temporary assemblies rather than nails or spikes.  The Torx head makes for a positive tip to fastener connection so removing the screws is just as easy as putting them in and they can be reused multiple times.

Since discovering these screws, I have pretty much completely discontinued the use of hex head lag screws.  I stock 5/16” diameter versions in 3”, 4” 5” 6” and 8” lengths  at all times on my tool trailer.  They have been used in cabinet installations, fireplace mantles, carports and decks, railings, gutters, shelving, and even door hanging.

To say that I am impressed with this fastener is an understatement.  Going back to “the way it was” will never happen.   The fastener industry realizes the increased popularity of this type of hardware and have come up with several variations including  thinner diameters, longer lengths, and different head configurations.

Next time you need to attach something with a lag screw, Forget About It, and try these Torx Lags instead.  You will be hooked and will never go back.


1 thought on “Torx Lag Screws”

  1. I am building a half dozen “Maloof style” barstools for a client but am having a hard time finding torx lags. There are many smaller torx screws used in these chairs (#10 X 3 1/2″)but the ones fastening the lower rungs and foot rest to the chairs are, in my opinion, too small in diameter. I need to remove these temporary smaller screws and replace them with a normal 1/4″ X 3 1/2″ lag bolt with a good shoulder; with one exception. The head!

    The barstool legs are counter sunk so that the head of the screw will be covered by a wooden plug. The counter sink holes are only 1/2″ in diameter. A normal 1/4″ lag bolt has a hex head that is too large to allow the coresponding driver fit inside the 1/2″ counter sink hole. The only solution is either a Torx or Allen wrench driven head. If those heads are slightly larger than 1/2″ diameter, no problem. I can grind down the O.D. until it fits.

    Thanks, Philip Greene,
    Wood Song Canoes
    (843) 835-8137

    425 Jessie Lane
    Round O, SC 29474

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