Building a staircase

[vati]

Hello,

I'm trying to model a staircase.. haven't done anything like it in solidworks before. I drew the steps and everything, to know where everything should be at and then went on to draw the frame, which will be made out out 2mm sheet metal. The frame's dimensions all through are 240x240mm.. all is good and fun until I get to the bend..
I've tried lofting it... sweep.. everything I could possibly imagine.. but only with the help of 3D Sketch splines do I get anywhere close to the desired end product.
I need the form to be continously unchanged shape of 240x240mm.. otherwise, when I flatten the surfaces - it comes out all wumbo-jumbo.. thus making all of this moot, because that's the thing i need most -the flattened shape of the bend for fabrication.

I hope someone can help me please!

Thank you!!

 

[Cadasio]

I cannot open your file as I don't have 2019, ut on first glance I would try to do a sheet metal lofted bend between two 3d sketches (perhaps do a fit spline on what you currently have), one of the inside and one for the outside as indicated by my highly detailed and accurate image...





The loftedbend will mean its uniform thickness and allow it to flatten you can then look at putting the slots in