Step 46 - Traditional mortise and tenon fixing
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 mortise. 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.
Step 47 - Traditional mortise and tenon
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.
Step 48 - Mark newel post for bolt fix method
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 mortise, cut into the newel. The fit between 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.
Step 49 - Prepare bottom newel
Find and mark the vertical centreline of the post on the bottom newel.
Mark a horizontal line, 125mm down from the top face using a square. Measure up 50mm from this and make another horizontal line.
Mark a vertical line 12.5mm from the centre, and a second line 25mm from that. This will give the outline of the mortise.
Step 50 - Cut out mortise
Mark a hole position 90mm from the top of the newel and a second one 22mm down from this (1). Set an adjustable bevel to the pitch of the stairs. Using a 20mm auger bit drill a hole, 35mm deep, at the same angle as the stairs, using the bevel as a guide (2). Drill a second hole vertically to a depth of 25mm (3).
Using a hammer and chisel, carefully remove the remaining material (4).
Step 51 - Mark out the tenon
Mark out the tenon on the handrail. Start by marking the centre, then mark two lines either side of this, 25mm apart. Mark a horizontal line 10mm down from the top of the rail, and along the top to the original mark.
Step 52 - Cut the tenon
With a fine cut tenon saw, cut along the two vertical lines forming the width of the tenon. Cut the horizontal line that forms the top of the tenon.
Carefully cut around the original mark to meet the tenon and remove the waste. Finally, cut the bottom of the tenon so it sits horizontally.
Step 53 - Check fit
Check the fit of the tenon in the mortise and adjust as necessary. Repeat for the top newel.
Once happy with the fit, the joints can be glued and fitted together, unless…....
For a really good joint, drill and dowel. 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/mortise - 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.
Step 54 - Fix handrail plate to handrail
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 the handrail. Measure along 2mm from this mark and drill through the tenon. Re-insert and assemble the joint. You should see that the hole in the tenon is offset in the direction of the handrail. 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.
