How to prevent lag bolts from breaking
Installing three-inch lag screws to install hanging garage storage shelves is often a source of frustration for many people. They often experience breaking. In this article I will give tips on how to prevent this problem.
The tips listed here may be applicable to any type of lag bolt use, however, my experience originates from mounting ceiling mounts 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 must pass through the drywall plus the width of the mounting bracket.
The most important thing to avoid breaking the screws is always predrill the holes. Use a 3/16″ drill bit and drill to the full length of a screw. When you only partially drill, you will get significant resistance when driving the screw. I’ve heard some people have success drilling an extra hole into that 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 may force you to move your mounting point.
Second year of use shocking driver to drive the screws. The job can be difficult 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 have found that I need to use both hands and stand directly behind the drill in order to successfully drive 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 line up with the screw. This is particularly useful if I am on a ladder and need to reach the anchor point.
Another common problem is people over-tightening the lag screws. Do not overtighten the hardware. If you turn the head once the top of the lag screw is already flat against the drywall, you risk twisting the head and causing the threads to bind inside the stud. This could cause problems with your ceiling mount bracket connection because you could be installing through the studs, meaning you won’t be able to just slide the bracket a bit to make a new hole. Turn the screws until the head touches the ceiling bracket. It is not necessary to tighten the screws further.
Apply soap or wax on the threads could simplify screw driving. You’d be better off using candle wax if you can, because soap can cause the threads to rust over time.
If you work with poor quality screws, consider a visit to the hardware store for better quality screws. Tea grade and the material of the lag bolts are marked on the head. No markings means the lowest grade 2 and has the lowest tensile strength. Three radial lines signify grade 5, a quenched and tempered medium carbon steel. This grade must spin properly and not have regular breaks. The final and strongest classification of steel bolts have six radial marks and are therefore grade 8.
Stainless steel lag bolts would not have these standard markings, but would have an approximate tensile strength of grade 5; however, they may bend more easily; later we will talk about how it folds. Stainless steel will probably have something imprinted on the head, so you won’t mistake them for grade 2. Stainless steel is also non-magnetic.
I would not advise reusing lag bolts Once actuated, even if only partially, the screw is under tension. It is more likely to break when you try to use it again. Which also suggests that you shouldn’t drive a screw running back and forth into the wood to get it to the proper length. Lastly, a small amount of bending in the threads will prevent the hardware from turning and drilling into the stud properly.