STAIRS AND STAIRWAYS

Many sets call for mutliple levels, which call for stairways.

Stairs consist of several parts:
	Treads- what you walk on
	Risers- the "step up"
	Carriages- Sides of the stairs, supports the treads

Carriages come is two forms.
Open carriage typically found onstage stairs.
	* May be made of boards
		+ Need additional support, legs, etc.
	* May be made of plywood
		+ Self-supporting, take more storage room.
Closed carriage typically used for escape stairs.
	* Usually built of all boards

There two general ways to describe stairs according to their support:
Independant- hold themselves up w/o attachment to platform
Dependant- held up by adjacent platform.

Long strairways rarely used; instead:

Landings
      * Platform part way down stairway
Rounders
      * Steps that go around corner   

Don't make the rounders too small.
Should be wide enough for your feet to fit in the center,
    i.e. center width of rounders should be same as rest of the treads.

Laying out carriages.

Calculating Rise to Run of Stairways
      * Rule of 18 Rise + Run = 18 (approx.)
               6" + 12" = 18"
      * Rule of 25 2xRise + Run = 25 (approx.)
              (2 x 6") + 12" = 24"
      * Rule of 75 Rise x Run = 75 (approx.)
               6" x 12" = 72


Stringers:
      Open "carriage" placed midway under treads.      

Tressle stairs
      * Flat frame gates used to support treads, somewhat like tressle legs.

Circular stairs
Tressle stairs are probably best way to make circular stairs.
	* Circular stairs quite tricky to build even as permanent structure.
	* Tressles strongest, most practical approach if don't need full circle.
        Tressles work fine up to 3/4 circle.

Fully circular stairs are difficult. 
If you must do full circle, may need more advanced techniques or 
a commercal solution, rather than a shop built one.

Ramps
      * May be built like platforms, with slanted tressle legs, 
        or like a house floor with plywood over joists.