. Carpenter. o-rary auxiliary structures on false workto support the voussoirs or parts ofstone, brick or concrete until the mor-tar or cement has hardened and becomeset and safe. These supports are termedcenters, and must be constructed ofcorrect geometrical shape, and in a way,both by nature of the form and material 44 THE CHRPBnTER employed to fully and safely carry thesuperincumbent weights which are to beplaced upon them. They must be fixed firmly in place, andyet, as they are for only temporary use,provision must be made for graduallylowering them in order to remove themwhen their missio
. Carpenter. o-rary auxiliary structures on false workto support the voussoirs or parts ofstone, brick or concrete until the mor-tar or cement has hardened and becomeset and safe. These supports are termedcenters, and must be constructed ofcorrect geometrical shape, and in a way,both by nature of the form and material 44 THE CHRPBnTER employed to fully and safely carry thesuperincumbent weights which are to beplaced upon them. They must be fixed firmly in place, andyet, as they are for only temporary use,provision must be made for graduallylowering them in order to remove themwhen their mission is fulfilled. There are many kinds of centers re-quired for different designs of arches,reaching from the simple brick lintel tocomplex groin—all of which demandcare, thought, and the most accurateworkmanship in their form and construc-tion. In an attempt to illustrate principleand show methods of construction, I willcommence at the simplest form, namelythat represented at Fig. 1, and while this SKEWEMCjj. Fig. 1.—Simple Fireplace Center. example may be considered elementaryand is certainly easy to comprehend, itinvolves the true system of view shows an open cavity, or fire-place, 2 feet 6 inches wide and three feethigh over which the bricklayer has tobuild an arch, or brick lintel. To con-struct the center necessary for this pur-pose, the carpenter would first use apiece of 2-inch or spruce or pinetwo inches longer than the width of theopening between the jambs and wouldjoint one of its edges. He would thensquare across both ends one-sixteenth CBOWHf Fig. 2.—Getting the Curve,inch shorter than the width of the open-ing, and draw a parallel line to and one inch from the jointed edge as shown inFig. 2. He would then divide this lengthinto two equal parts and square acrossthe division point. Then, laying theboard down on the bench and tacking itthere, he would drive three nails, one ateach springing where the curve cuts theparallel line, and one at
Size: 1917px × 1303px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, bookidcarpenter33u, bookyear1913
