Double Ended Lag - Handrailing Hardware Screw
A double ended lag screw can be used to attach balusters to the base of stair treads. You're probably not going to find these at your local home improvement center or hardware stores.
They come in different shapes and sizes and might need to be ordered from a stair supply warehouse. As a matter of fact, I haven't ever found them anyplace else. The invention of double ended lags has been a blessing to most stair building professionals.
Stairs / Stair Glossary
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