Handrail:  There are two types of handrail to choose from depending on what style or type of baluster or spindle is chosen.  The first type is handrail that has a groove or plow on the bottom, the same size as the square top of the baluster.  This type is called plowed or ploughed handrail and is most often used in a post to post stair system, and may be used with shoe rail in the case of knee wall construction.  The second type is handrail that is smooth on the bottom and has to be drilled to accept the tapered top baluster.  This is called solid handrail and is most often used in an over the post or post to post with fittings stair system.  Wall rail and bending handrails are other categories of railings that are used in stair construction.  Wall rails are attached to building walls to enable the user of the stair system more stability in their climb or descent.  Bending rail and bending rail moulding are used by skilled carpenters in very special projects with sweeping staircases.