The handrail may be fixed using the traditional method of mortise and tenon. This entails shaping the end of the handrail to form a protrusion (the tenon) and removing material from the mating part to form the mortice. The two are then brought together, glued and mechanically fixed together using a tapered dowel pin.To use this system, insert the spigot part of the newels into the newel bases but do not fix yet. Place the handrail between the newel posts and set to the correct height. Use a clamp and timber offcuts to help you achieve this. Place the handrail into position so that the top of the handrail is at least 900mm from the pitch line/stair nosing and the same height at both ends.
Make vertical marks at each end of the handrail following the inside face of the newel posts. Continue the mark all the way around the handrail using a square.Mark a second line 75mm out from this (so that the handrail length will now be 150mm longer than the inside distance of the newel posts). Again, continue the line all the way around. Cut this outer line with a fine-toothed handsaw. Traditionally, the handrail would be fixed using a mortise & tenon joint. This involves cutting the end of the handrail to form a leg or protrusion known as a tenon.
This tenon then fits into a hole, known as the mortice, cut into the newel. The fit b etween the two should be a slight interference fit so that the tenon can be pushed or gently tapped into place.Using this method entails a little carpentry skills, but never-the-less, can be achieved if one takes their time. A mortise and tenon joint produces a strong joint and leaves no external holes that would require filling or covering.
Aluminum Handrail Posts
Check the fit of the tenon in the mortice and adjust as necessary. Repeat for the top newel.Once happy with the fit, the joints can be glued and fitted together, unless you choose to drill and dowel, which makes a strong joint. The joint will be pulled in really tight.To do this, remove the handrail and using a 12mm bit, drill the newel 20mm in from the mating face and central to the tenon/mortice - about 110mm down from the top of the newel. Drill as far through as you can without breaking through the opposite side of the newel. Re-insert the handrail tenon fully into the mortise. Using the same drill bit, drill just enough to make a slight mark on the tenon.
Remove handrail. Measure along 2mm from this mark and drill through the tenon. Re-insert assemble the joint. You should see that the hole in the tenon is offset in the direction of the handrail.
How To Install Newel Post
After gluing the joint, insert a dowel pin, slightly tapered and of the same material as the newel. Hammer in, drawing the handrail tight into the joint. Cut the dowel and finish flush with the newel.