Installing Wooden Tapered Balusters
Mike5000
| Posted in Construction Techniques on
My new stairs are finished and the only thing left is to install the turned, wooden balusters. The bottoms have 3/4″ diameter tenons and they are round and tapered at the top.
The tenons are 3/4 to 1″ long. How much of the tenon do I need to leave before installing? This will determine how deep the mortises in the hand rail have to be, as the railing is already fixed.
What kind of glue is best; construction adhesive, polyurethane or yellow wood glue?
What size finish nails should I use to secure the balusters to the stair treads and ralings?
This is my first time doing this, so any tips you can provide are greatly appreciated.
Thanks,
Mike
Replies
If the railing is already in place, the holes in the rail will have to be drilled 3/4" deeper that what you would normally need for the top tenon. You'll have to put the top of each balluster in, raise it enough to let the bottom tenon in, then slide it back down to seat the bottom tenon in the treads. Usually, the top of the balluster is of an equal size for a few inches before it starts to taper. Often, you use two different length ballusters per tread to account for the difference created by the slope of the rail. You are going to have problems if you have to cut ballusters and get into the taper. If the top of the balluster reaches into the rail 1" or more, you should be fine. Traditionally, glue isn't used. A small finish nail, #3 is placed in the top of the balluster into the railing from the back, usually from the stair side, tucked in close to the top of the railing hole where it dosen't show. Predrill and set the nails. Toenails in the bottom will only go into the tenon and do nothing, you don't need any. No glue makes fixing or replacing parts much easier in the future. Glue won't hold with a round tenon in the face of a tread due to the movement of the tread expanding and contracting with humidity changes. Too many folks try to make things last forever and over do, making future repairs very difficult. Polyurethane glues foam up and can make a mess. Construction adhesive is too thick for these type of applications. If you must, use ordinary yellow glue on the bottom tenons.
Ordinarily, the railing is cut then turned end for end and placed upside down on the treads. This allows you to drill for the ballusters and helps keep the holes going plumb. Then, the rail and the ballusters are wrangled together as the railing falls into the proper place. With the rail in place, you will have to drill up into the rail while keeping the bit plumb in two directions, you'll also have to drill deeper as stated above. You can place a wrap of tape on the drill bit so you don't accidentally drill too deep and come out the top of the rail. If you don't drill plumb, the square above the bottom tenon won't fit correctly to the tread and you may have to bend the ballusters. A Speedbore, type bit with that flat, extended tip helps when starting the bore on a slope but you have to be careful that tip doesn't poke through. You don't want the holes too tight in the rail.
Drilling Handrail
Mike 5000,
You can't get a better reply than Hammer1's comments. He thoroughly lays out what needs to be done.
I'll add that making a simple drilling fixture set at the stair angle will greatly speed up the drilling process while increasing accuracy and consistancy. I make them by drilling the size hole you need through the end of a 2x4 block and then cut one end off at the stair angle with a miter box. Fasten a piece of plywood to this block so you can clamp it to the handrail at each balluster location then use a tape depth gauge as suggested.
Hope this helps... let me know if this doesn't make sense and I'll cover making the drilling block as a topic on The Digital Jobsite blog.