Flush Bolt - Stair Construction And Handrails
A flush bolt would be any bolt that was countersunk into a piece of wood and doesn't protrude above the finished surface of wood. Sometimes these bolts can sit below the surface of the wood and still be considered flush bolts.
If you look at the drawing above, you will notice that
the black arrow is pointing to the top of a flush bolt, but the bottom
of the bolt, wasn't countersunk into the wood and is therefore sticking
out, well beyond the finished surface.
It all depends upon the design of your stairway, whether or not you're going to use a flush bolt (top of picture, above), countersunk bolt with a wood plug covering it or leaving the head of the bolt, on the outside of the finished board (bottom of picture, above).
Try to avoid over drilling flush bolts on boards that aren't very thick. One time I watched a stair builder drill a 3/4" deep hole for the flush bolt in a board that was only an inch and a half thick.
I'm not going to go into all the details, but the stairway and handrail needed to be remodeled by someone else.
Stairs / Stair Glossary
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z