Stringer newel – Determine the stringer shoulder line.

How to determine the stringer shoulder line.

When fitting the stringer to the newel you will need to know where to set the shoulder line on the stringer; to allow the handrail and spindles to sit in the correct position when running across the landing. This is done by first figuring out the position of the trimmer face on the landing. once again we are back to knowing the centre line of the spindles and offset this by half a spindles width. The last riser face from the flight of stairs will align with the trimmer face.
Determine the stringer shoulder line.

Determine the stringer shoulder line.

Choose your spindle
Before we can do anything we need to know the spindle size, we can then set the spindle central to the newel post and offset by half the spindles width to get the fascia position, the fascia position will align with the face of the last riser in the flight. using a thinner spindle will allow the use of a smaller newel without the nosing from the treads and landings protruding outside off the post in an awkward looking manner. This is of course if you use traditional nosings that project in front of the riser by the thickness of the nosing.
With a 35mm or 1 3/8" spindle we can use an ex 4" or 100mm newel comfortably, when using a 1 3/4" or 44mm spindle the nosing will project in outside the newel post by about 1/4" or 6mm, this leaves a small bit of nosing that just looks odd. In this diagram you can see how the newel aligns when setting out for: 1 3/8" - 35mm spindle.
1 1/8" - 28mm Tread.
ex 4" - 100mm Newel post.
You can see here that the nosing stays within the newel post.
The newel alignment with 35mm spindle.

Aligning the newel over the stringer 35mm spindle.

Newel post with larger spindles

With the larger spindle the newel moves farther into the landing and therefore the newel face also moves farther into the landing area. In this image you can see how the nosing protrudes outside of the newel when we use a larger spindle, in this situation, it is generally better to use a larger newel post to keep the spindle within the newel area. In this diagram we have changed to:
1 3/4" - 45mm spindle.
1 1/8" - 28mm Tread.
ex 4" - 100mm Newel post. This would be farther exagerated if we were to use a 35mm or 1 3/8" tread thickness as this would increase the nosing projection by a farther 16mm or 5/8".
The newel alignment with 44mm spindle.

Aligning the newel over the stringer 44mm spindle.

The stringer shoulder cut and tenon formed

In the example I have used the 35mm spindle set up. Here you can see the end of the stringer with the shoulder cut and the tenon formed.
Stringer with shoulders cut and tenon formed.

Stringer with shoulders cut and tenon formed.

The stringer shoulder at the starting newel


The tenon and shoulder line are formed in the same way at the starting newel post, when this post is on the ground floor you do not need to worry about the position of the landing fascia, it is, therefore, possible to select a position that ensures the nosing is sitting comfortably within the newel post, unless the post is being set back one going to allow for a feature tread to be set in front of the newel.
When choosing a position for the tread it is advisable to keep in mind the position of the draw dowel that will be behind the first riser, it is also good practice to allow room for the riser wedge to be cut into the newel, should this not be practical then the bottom riser may be screwed through the back and into the newel at an angle to ensure it does not come through the face of the riser or break out through the face of the newel post itself.
Stringer with newel fitted.

Stringer with newel fitted.

The bottom stringer shoulder at a landing newel


When the newel is set on a landing, the tread position will be determined as at the top of the flight, these are not individual flights but one continuous flight with the landing being thought of as a large tread, without this in mind the stairs may not connect properly. In this diagram, you can see the setting out for the landing nosing and the first tread of the upper flight.
From this information you can determine the stringer shoulder line. In this example we will be using;
1 3/8" - 35mm spindle.
1 1/8" - 28mm Tread.
ex 4" - 100mm Newel post.
Landing nosing and bottom tread position.

Landing nosing and bottom tread position.