Wood craft forms a major part of a home's interior. The upward steepness of a staircase in a colonial-style home, for instance, will give the impression of both height and space. However, broken or damaged wood spindles will interrupt the flow of the mortise and tenon staircases.

You need to repair or replace the damaged wooden spindles from the staircase as soon as you notice them. First, remove the portion of the stair tread on the outside of the spindle, which is the stairs’ end cap. For that, chisel the seal in between the end cap and the tread with a small pry bar. Once the top is free, loosen the bottom of the spindle with your hands. When you remove the spindle, go slowly and take care not to damage the handrail or surrounding wood spindles.

Now prepare the staircase by putting the end cap back on the stair tread and measure from this point to where the spindle will meet the handrail on the stairs. Mark down the measurements somewhere you can easily retrieve the information. Once you get the model you need from a wood craft store, measure the bottom edge of the spindle and cut the top edge for matching the slant of the handrail.

Hold a T-bevel under the handrail and affix its nut to secure the angle. Now line up the inside corner of the angle as per the noted measurements. In addition, mark the angle with pencil and cut the top of the spindle with meter saw – this step may take time; you can call a wood turner to get perfection, if you want.

Put the small tenon into the mortise, and line up the top in the middle of the underside of the handrail. If the tenon is smaller, wrap around the underside of the handrail, glue it tightly, and use a level to ensure that it stays upright. Additionally, make sure that its angle matches the rest of the spindles to install the top of the spindle.

Note that when replacing wood spindles on a mortise and tenon staircase, you need to have the exact design as the one before. You will also need to affix the wood spindles on the handrail with a mortise and tenon joint at the bottom with nails at the top.