The old doorknobs you saved or collected aren't doing much good in a drawer or a box. But they could be holding up your jackets, coats, umbrellas and bags in the hall or mudroom if you mount them on a board or decorative piece of molding. No matter what kind of posts your doorknobs are mounted on, you can secure them in place for a stylish and economical coat rack.
Find dummy spindles that are small enough for the hollow doorknob posts to slip over snugly. Or, look for spindles that will screw into the posts -- you might get lucky and find a match. Get one dummy spindle for each doorknob.
Select and prepare a wood backing for the coat rack knobs -- a piece of decorative molding, a weathered barn board, a distressed length of wood. Try out the doorknobs on the front of the backing to determine spacing.
Measure and mark the vertical and horizontal position for each knob on the backing board. Center a dummy spindle over the point where the two lines meet. Screw the spindle firmly to the wood board.
Place a decorative metal rosette or backplate over each spindle and screw it to the board. The decorative cover hides the base of the dummy spindle. The spindle itself sticks up through the hole in the rosette or backplate.
Apply silicone adhesive to the spindle and slip or screw the doorknob onto it. Allow the glue to dry completely before hanging or bolting the coat rack on the wall.
Prepare the backing board and measure to mark the places where you plan to attach the doorknobs.
Remove the old spindles from the doorknobs. Square spindles and other odd shapes that are secured with a side screw are simple to remove -- and you can't fix the knob to the backing board with them.
Tape over the small hole in the side of the doorknob post; turn the knob upside-down, and fill the hollow post to the rim with liquid resin. Let the resin dry according to the manufacturer's instructions.
Drill a hole in the hardened resin, just a bit smaller in circumference than the hanger bolts. Insert a hanger bolt into the hole in each resin-filled doorknob post. Grab the bolt with a locking pliers and screw it into the resin, leaving enough of the bolt sticking up to screw into the wood backing.
Screw the doorknobs to the wood backing bar at the marks and hang the bar or secure it directly to the wall with wood or plaster screws, ideally at the wall studs.