How to Install Stair Spindles

Question

How do I determine an equal size to cut each spacing block when figuring a maximum 4" between spindles? I want a 4" maximum spacer after the first post and before the last post, but no matter what I do I end up either short or long at the end!

Answer

I think what is happening in your case is you are measuring the slope of the handrail and the horizontal distance between spindles, which are two different measurements.

To clarify the building code: It is not just 4" between spindles that is necessary, but that a ball of 4" in diameter cannot pass between the spindles. (The 4" ball refers to a baby's head). If the spindles have deep turnings on them, you can see what the code is referring to.

What I do is instead of using 4" between posts is figure on 5" centers of spindles. This gives 3 1/2" between. Usually two spindles will work per tread. You not only have to have the spindles evenly spaced, but they should be the same placement on each tread. This requires a bit of fiddling.

Don't be too set on having the first and last spindle the same as your spacing between the spindles themselves. What is important is that the distance between the first and last spindle is the same and that it prevents a 4" ball from passing through the space. Rather than start at the ends, work from the center of the section each way.

On different length sections use the same spacing between spindles, but differ the spacing between the first and last spindle and the newel post or wall.

Another tip, if the spacing at the ends of the section are too close or too distant, change your center point on a space instead of a spindle or vice versa.

You will notice that figuring on 5" centers will be easier than figuring on a space. Rather than dry fitting everything, try laying out the location of the spindles on the handrail with painter's masking tape to mark on. Once the centers are determined, lay out the position of a few spindles to calculate your spacer blocks. The first and last will probably be different than the typical blocks between spindles.

Lay out all the sections before cutting anything to see if the spacing works for all of them. A slight adjustment may be needed to satisfy all the sections and to maintain your selected spacing between spindles.

Dave