Ellsworth M. Longfield

“ Problems on the Rise of the Miter Line.—An elbow is always measured by the degrees of the angle formed by straight lines drawn from its extremities to the center of the elbow, Fig. 77. Since all backsets in the same elbow are equal, the value of the backset can be expressed in degrees. A five-piece elbow has 8 backsets. A five-piece 90° elbow would have each backset equal to 90°÷8 or 111⁄4°. The first piece of any elbow contains one backset, the last piece one, and every other piece contains two. ”

“ The distinction between a rake moulding and a raked or raking moulding should be noted:
A rake moulding is simply a moulding that is inclined to the horizontal. It has the same profile as the horizontal moulding to which it is joined.
A raked or raking moulding is an inclined moulding that joins a horizontal or other moulding that does not lie in the same plane. It does not have the same profile as does the moulding to which it is joined. It takes its name from the fact that its profile must be altered or raked in order to join with the other moulding. ”

“ The practice of assuming a section, common to some drafting rooms, results in a more or less distorted fitting, according to the experience the draftsman has had in designing such fittings. The workman in forming and assembling the fitting has difficulty in that he must compel the assembly to take an unnatural shape.
The plan, Fig. 301, is first drawn according to the dimensions taken at the job. The profiles are then divided into the same number of equal spaces. After the order of triangulation has been determined, base lines are carried to the corners M and N of the rectangle. ”

“ The Boat Pump.—A boat pump consists of a straight piece of pipe called the barrel, to which is attached a frustum of a cone (the funnel) . A tapering spout is riveted and soldered over an opening in the pump barrel. Into the lower end of the pump barrel a "lower box" is soldered. The "lower and upper boxes" may be obtained from almost any supply house. The upper box is threaded to receive the pump rod. The pump rod has an oval handle formed upon its upper end. ”

“ The diagram of triangles and sections, Fig. 319, is now constructed by taking the base lines from Fig. 317. The triangles have a common altitude equal to lines 6–A of Fig. 315. One of the perpendiculars in each section also has this altitude, but the altitudes of points O, N, M, K, and H are made to correspond to the altitudes of similar points in the true section, Fig. 316. The pattern, Fig. 321, is started by placing upon any vertical line a distance equal to the true length line 6–A. The development proceeds in the usual manner until completed. ”

“ Since the pattern for all pieces can be laid out from the pattern of the first piece, it follows that all necessary information can be obtained from an elevation of the first two pieces of an elbow. A draftsman rarely draws more than two pieces of the elevation and divides the arc of the throat instead of the arc of the back. ”

“ Square Return Miter.—Figure 245 shows the profile of a moulding. Mouldings are seldom of standard design, although the architect builds up a given design from standardized parts or members. In the profile shown, the compound curve is known as an ogee. This shape is encountered more frequently in mouldings than any of the others. Line 9–10 of Fig. 245 is often referred to as a "fascia," which is a plain band or surface below a moulding. Line 10–11 of Fig. 245 forms the drip of the moulding since it compels the water, flowing down the surface of the moulding, to drop off. ”

“ The most accurate method of obtaining the cost of material entering into their manufacture is to lay out a full size pattern, arrange the several pieces so as to produce a minimum of waste, and compute the area of the rectangle thus obtained. ”