Winding Stair Stringer Issue

[robindemey]

That's the problem. When I extrude the line (the helix), I can give a height. But this number 1 in my drawing and that's not what I need.

[SLW210]

A² + B² = C²

 

Height 2² + Height 2² = Height 1²

[SLW210]

Maybe you can just depict what your final result would be?

[robindemey]

Final result should be something like that: http://www.cadtutor.net/forum/showthread.php?65439-Winding-Stair-Stringer-Issue&p=447002&viewfull=1#post447002

But I'd like it to be smooth.

 

Your pythagoras isn't correct, because I only know 1 side (height 2=300). The angle of the stringer is'nt easy to know, because it's a helix.

[Bill Tillman]

... Do you know that when you extrude a line it creates a surface and that surface can then be given a thickness? That is basically what was done for the stringer in Bill's original drawing.

 

Yes, but with all due respect, recall that this method will only produce a drawing for presentation. It may not geometrically represent what it takes to fabricate a curved stringer. This is the quandry with curved stringers. You go to a great deal of trouble to lay it out and then the guys who make just wing it. It's very difficult to do 3D layouts in reality (not AutoCAD) when dealing with a 144" high run and the stringer has a 96" or larger diameter, plus the darn thing weighs 400 lbs.

[SEANT]

It requires some pre-processing before applying the Pythagorean theorem. The attached DWG is based on an arbitrary turn count, rise, and radius. I did base the stringer width on 300.

Example.dwg

[ReMark]

I think of couple of you guys underestimate what a good fabrication shop can do. Heck, these kinds of problems were being tackled long before computers we even invented.

[stevsmith]

I find it easier to draw a spiral stair for manufacturing using plain 2d and manually working out the development.

I think you'll find thats why it could be tackled long before computers.

[Bill Tillman]

I think of couple of you guys underestimate what a good fabrication shop can do. Heck, these kinds of problems were being tackled long before computers we even invented.

 

Yes, and some of these guys are true masters of their crafts....but I also see them getting by with 1/4" and sometimes 3/4" shim as required space. One thing I learned early in my drafting days doing oil field equipment in Kilgore, TX was to apply these notes to all drawings:

 

1. Cut to fit

2. Weld to hold

3. Grind smooth

4. Paint to match

[SLW210]

You are not going to fabricate the stringer in one piece, so why draw it in one piece. Like stevsmith stated, for fabrication drawing, work out the development in 2D or you can 3D this, but in the same manner as constructed.

 

It can be fabricated in one piece, if you have the equipment and material.

 

I would make it so the pieces were less than 50 lbs.