: Practical Stair Building and Handrailing By the square section and falling line system. by Wood W H - Stair building; Hand-railing

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PRACTICAL

STAIR BUILDING AND HANDRAILING.

Stairs are a succession of steps leading from one landing to another in a building. Each step comprises tread and riser, the tread being horizontal and the riser vertical. The side pieces supporting the ends of steps are called strings: that next to the wall, the wall string; the other, the front, outside, well, cut, open, or close string. When the steps are narrower one end than the other they are called winders. The landing is a platform between the floors, and it is sometimes arranged to give access to a door. A succession of steps between each landing is called a flight. It is not often that the stair builder is called upon to say how and where the stairs are to go, that being the work of the architect; but the former must do his best to carry out the wishes of the latter, who will leave to him the placing of risers, and all details necessarily belonging to the stair builder, who will make the best possible job, having all easings and falling lines as graceful as it is possible to make them. An easing that is too long is almost as objectionable as one that is too short.

He will take the dimensions off on to his rods, and from them set out the whole stairs, showing all doorways, landings, headroom, &c., to 1 1/2 inch scale if possible. All winders must be set out full size.

ELEMENTARY PROBLEMS.

Fig. 1. Draw a straight line, equal in length to the semicircle A B C. With A and C as centres, and for radius A C, strike the two arcs to intersect each other in S. Join S A and S C extended, to cut the line through B in D and E. Then, D E is the length of the required line, and if this was bent around the semicircle it would reach from A to C. This line throughout this work is termed the stretch-out of the semicircle.

Figs. 3, 4 and 5 show how to bisect any given angle. Let A B C be the given angle. With B as centre, strike the arc D D to any radius. With D D as centres, and for radius more than half the distance D D, describe arcs intersecting in E. Then, a line from B to E will bisect the angle.

Figs. 6, 7 and 8 show how to ease any given angle, that is to form a curve that will connect the two straight lines, from any two given points, on those lines. Let A B and B C be the two lines forming the given angle, and it is required to connect those lines from A to C. Divide A B and B C into any number of equal parts, connect those parts, and the curve will be formed if A B and B C has been divided into a sufficient number of parts.

Fig. 9 shows a semi-ellipse, A B being the semi-major axis, and B D the semi-minor axis. Let A B and D B, Fig. 10, equal A B and D B, Fig. 9. To strike the curve, move this rod around, keeping D on the major axis, and A on the minor axis, and mark off points at the end of the rod all round.

Fig. 11. Given a semi-ellipse, draw a normal tangent. Determine the foci of the ellipse F F. With D as centre, and for radius A B strike arcs of circles at F F. At any point on the curve, say at S, draw lines to F F and bisect the angle. Now draw through S, square to this line that bisects the angle for the required normal tangent.

CLOSE NEWELLED OR DOG-LEGGED STAIRS, THE SETTING OUT OF RODS, ETC.

Fig. 1 shows the plan of a dog-legged stair. The first thing to be done is to take off the sizes on a rod. First take the rod, marked Fig. 3. Cut this rod in between the brick walls, taking care to try it between the walls where the two flights come together at risers 12 and 13. Set off on each end of this rod the thickness of plaster; now set off the face of wall strings so that they will be flush with the face of the skirting. Then set back from face of the string half an inch, the depth of the housing, this will be the end of the treads and risers. Next set off the centre of the rod, draw the newel and string on the rod, half their thicknesses on each side of the centre line. Then set back towards the centre from each face of the centre string, half an inch, the depth of the housing. This gives the length of the treads and risers; and if ordinary care is taken in setting out this rod, and working to it, no mistake can be made.

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