Splice stringer

[Fixarjon]

Planning to build a longer staircase on a slope. Thinking of buying pre-made stringers. But need to splice two together. What's the best way to do this? One idea was to just attach a plank on the inside and screw it together. Do you think this would work?

 

[Peter787]

Going to build a longer staircase on a slope. Was thinking of buying ready-made stringers. But need to splice two together. What's the best way to do this?
One thought was to put a beam on the inside and just screw it. Does this work you think?

It's easy to make your own stringers; the picture from Beijer clearly shows the parts.
The advantage of making the stringers yourself is that the staircase can follow the slope; otherwise, ready-made stringers usually have the same angle, slightly lower than 45°.
Otherwise, a beam on the inside or outside works well as you yourself suggest.