Wooden dowel pins are used in construction, furniture making and craft projects to join two pieces of wood together in place of more noticeable fasteners, such as screws or nails. Over time, it is possible for dowel pins to loosen or for the hole they rest in to round out slightly and allow the pin to slip. In this case, packing the hole tightly and using wood glue makes the bond tighter. Repair takes only a few minutes and returns the bond back to its original hold.
Remove the pin from the hole and lightly rub it with fine-grit sandpaper to take off any dried glue or other items stuck to it.
Roll up a strip of sandpaper the same size as the hole and insert it into it. Slowly rotate the rolled sandpaper to remove anything in the hole that doesn't belong in it.
Test the fit of the dowel into the hole and examine it to see how loose the dowel is. Break a flat wooden toothpick so it is the same length as the dowel. Break more than one toothpick if the dowel requires it to make a tight fit.
Apply a few drops of wood glue into the hole and use another toothpick to smear some up onto the sides of the hole.
Insert the dowel and toothpick pieces into the hole and use a light duty hammer to gently tap it down all the way into the hole. Use a utility knife to trim away any toothpick pieces that extend out of the hole.
If a dowel is very loose, cutting a new pin to fit the hole using a larger diameter dowel also works.
Don't trust the wood glue only. In most cases, whichever bond the glue gives breaks down in a short time if there is not more holding the dowel in place.