Lag Screws - Building Hardware
A lag screw has the head of a bolt on it, but has the threads of a screw. In the picture below, the black arrow is pointing to three lag screws that will be used to attach the angle stair tread bracket to the stair stringer.
Lag screws come in different shapes and sizes and are made from different metals.
Lag Screw Shopping Advice
If you're going to attach a galvanized stair tread bracket or other
angled brackets, that are used for stair building, make sure that you
purchase matching lag screws. A good example of this would be the
picture above, we're using a galvanized metal stair tread bracket and
galvanized lag screws.
Some metals don't work well together and if it's possible, try to find
compatible bolts, nuts, screws and lag screws to make the necessary
connection.
What Size Lag Screws Should I Purchase?
The best thing I could do is give you an example, using the picture above. I'm going to attach an angle bracket that had three 5/16" wide holes. I was going to install the bracket on to a 2 x 12 that was 1 1/2 inches wide so I purchased 1 1/2 inch long by 5/16" in diameter, lag screws and they worked fine.
Measuring Problems
Over the years, I have had problems measuring lag screws and bolts, when
ordering them for my construction projects. It wouldn't be a bad idea to
measure these bolts, before purchasing them.
Sometimes an 1 1/2 inch lag screw isn't 1 1/2 inches long. For instance
the overall measurement of one type of lag screw, from the bottom tip of
the screw to the top of the head of the lag screw head, is 1 1/2 inches
long. There have been other times where I have measured the bottom tip
of the lag screw to the bottom of the lag screw head and came up with
the same measurement.
This could create a problem, especially if your measurements are
incorrect, causing every one of the tips of your lag screws to stick out
of the outside stair stringer.
Stairs / Stair Glossary
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