Wooden plugs are tapered, round pegs that can be used to conceal the countersunk hole used to join the wood. A professional woodworker installs the plug into the countersunk hole on the railing or at any place where screws are used to join wood. They will install the wood plug with glue aligning the wood grain of the plug in the same direction as the wood railing being plugged, so it does not affect the aesthetic appeal of the woodwork.

Wooden plugs are also used when stain grade material may cause a dilemma and using wood fillers to hide the holes may seem tough. Many carpenters install the wood railings with screws and nails – usually anchored to the post – by toe-nailing or by drilling screws at a certain angle. It is typically easy to fill the nail holes when 16-penny nails get installed by toe-nailing, but that might not that easy with screws.

When it comes to carpentry and woodworks, professionals will pre-trim wood dowels and plugs to get the desired shapes. However, wooden plugs can also be availed from a wood craft supplies store in pre-trimmed shapes. Apart from that, you will need to pre-drill the hole on the railing and install a fastener shaft to join the wood.

Drill half an inch deep hole in wood with a countersink drill and drill straight in by keeping the drill bit at a 90-degree angle to the material. Then drill a hole on the wood to join it with a drill bit of the same size as the fastener shaft diameter. If you are installing railings, then you may need to deepen the hole to an inch or more away from the end of the railing and at an angle in order to install the screw through the railing and into the post.

Once you are done with drilling the hole, place wood glue around the edge of the wooden plugs, install the same into the countersink hole, and align the plug grain with the wood grain on the railing. Tap the plug lightly into the hole with a hammer until it fastens and allows the glue to dry up. When doing so, make sure not to touch the countersunk rim with the drill chuck as that may damage the rim and make the plug visible after the work is done.