Attaching three-inch lag screws to install hanging garage storage shelves is often a source of frustration for many people. They often experience them breaking. In this article I will give tips on how to prevent this problem.
The tips listed here can be applied to any type of lag screw use, however my experience originates in mounting ceiling brackets for ceiling mounted garage storage racks. These types of shelves require a 2 “insert into the stud. Most of these shelves include 3” lag screws as they need to pass through the drywall plus the width of the mounting bracket.
The most important thing to do to prevent screws from breaking is always pre-drill the holes. Use a 3/16 “bit and drill to the full length of a screw. When drilling just one part, you will get significant resistance while driving the screw. I have heard that some people have had success drilling an additional hole inside with a Drill Bit. 15/16 “, but only drill to the smooth area of the lag screw. Understand that wood is a natural product, therefore there is a chance that you will come across a knot inside the wood. These areas generally do not accept a screw well and therefore can force it to move its mounting point.
Second, use a shocking driver to drive the screws. The job can be tricky with a socket wrench. A cordless drill with the socket bit will do the job. However, by far the simplest solution is to use an impact driver. I found that I need to use both hands and stand behind the drill in order to successfully operate them with a rechargeable drill. However, if I use an impact driver, I can install the screws with one hand and I don’t have to align with the screw. This is particularly useful if I am on a ladder and need to reach out to the anchor point.
Another common problem is that people over-tighten the lag screws. Not to do tighten too much the hardware. Turning the head after the top of the lag screw is already flat against the drywall may cause the head to become twisted and the threads to jam inside the stud. This could cause problems with connecting your ceiling mount bracket because you may be installing through the studs, which means you won’t be able to just slide the bracket a little bit to make a new hole. Turn the screws until the head snaps into the ceiling mount. It is no longer necessary to tighten the screws.
Apply gold soap wax over threads could simplify screw placement. You’d better use candle wax if you can, because soap can rust the threads over time.
If you are working with poor quality screws, consider visiting the hardware store for better quality screws. Tea qualification and the material of the lag screws are marked on the head. No markings means the lowest grade 2 and has the lowest tensile strength. Three radial lines mean grade 5, a quenched and tempered medium carbon steel. This grade must rotate properly and have no regular breaks. The final and strongest grade of steel bolts has six radial marks and is therefore grade 8.
Stainless steel lag screws would not have these standard markings, but would have the approximate tensile strength of grade 5, however they can bend more easily, more when bending later. Stainless steel will probably have something printed on the head, so you won’t confuse them with grade 2. Stainless steel is not magnetic either.
I would not advise reusing lag screws. Once actuated, even if only partially, the screw is put under tension. There is a greater chance that it will break when you try to use it again. Which also suggests that you shouldn’t install a screw running back and forth in the wood to bring it to length. Lastly, a small amount of bend in the threads will prevent the hardware from rotating and drilling properly into the bolt.
