How to Replace a Railing Spindle on Stairs

With any luck, you have a couple of leftover spindles from the original installation hiding in your storage area. But if not, before removing anything, take precise measurements of your current spindle to ensure you purchase the correct replacement. Measure the railing height, including the length from the bottom of the top rail to the top of the bottom rail or stair tread. Also, measure the diameter or width of the spindle, as they come in various sizes. 

Take note of the spindle's style and material—whether it's wood, metal, or composite—and any decorative details that need to match your existing railing design. This is also a good time to inspect the surrounding railings for any other damage that may need attention, so you can address everything at once.

Take your measurements and a photo of your existing railing to your local home improvement store. Most stores carry standard spindle sizes and styles, but you may need to special order if you have an unusual design. Consider buying an extra spindle or two in case you need to make future repairs. If it’s an outdoor staircase, ensure it meets local railing requirements for decks and building codes.

Put on safety glasses and work gloves before beginning removal. Most spindles are secured with screws from underneath the top rail and into the bottom rail or tread. Use your drill to carefully remove these screws, keeping track of their size and length for reinstallation. If the spindle is glued in place, you may need to gently work it loose with a chisel and hammer. For spindles that are dadoed (set into grooves), which is more common in older or custom wood railings, you might need to cut them out with a hacksaw, being careful not to damage the surrounding railings.

Once the old spindle is removed, clean out any debris, old glue, or wood shavings from the mounting area. Sand any rough edges smooth with 120-grit sandpaper to ensure a clean fit for the new one.

Before permanently installing your replacement, do a test run to make sure everything aligns properly. The spindle should fit snugly between the top and bottom rails without forcing it into place. Check that it's plumb using your level, and verify that the spacing matches the existing spindles on either side. If the fit is too tight, lightly sand the ends of the spindle to achieve a better fit. If it's too loose, you may need to add shims or use a slightly larger spindle.

Pre-drill pilot holes to prevent the wood from splitting, especially if you're working with hardwood spindles. Apply a small amount of wood glue to the contact points where the spindle will meet the rails. Position the spindle carefully and secure it with screws from underneath the top rail and into the bottom rail. Make sure the spindle is perfectly vertical before fully tightening the screws.

If your new spindle doesn't exactly match the color or finish of your existing railing, you'll need to apply stain or paint to blend it in. Clean the spindle with a cloth to remove any dust, then apply your chosen finish according to the manufacturer's instructions. For best results, consider touching up or painting the stair railing in its entirety to ensure a uniform appearance. If the entire staircase is in rough shape, consider refinishing the stair railings all the way up. Allow the finish to dry completely before letting kiddos or pets run up the stairs.