the work. To make this quite clear: the architrave moulding shown in section at top of Fig. 4, and in detail at Fig. 5. contains, in its finished state, eleven arrises, which require eleven lines on the rod to indicate them. Now all that is required to draw the moulds are four lines, the inner and outer edges of each piece. When the stuff is cut to this shape, the machinist will automatically produce all the others with correctness, by working the face edge against the " spindle," therefore these extra lines are not only useless on the rod, they are confusing, also when the work man is trying the moulds on, he requires to keep following the path of such lines around, to make sure he is dealing with the right one.
To set the Rod out.—Draw the springing line and a centre line at right angles to it, squaring from lower edge of board. Draw in the frieze rails and stiles, also section of the architrave 011 one side exactly as they occur on the width rod. Strike the door head with a beam compass, also the curved panels; mark in the radial joint line. Next consider what is required in the way of moulds. There will be, in the present case, one each for back architrave M; bed mould B ; ground G ; solid rebate E ; soffit stile or head I.; and panel of same, also one for panel of door; this latter is shown in the second line on right side of door. The various moulds are indicated by the above letters in the example, and the same letters are used on the enlarged section for reference. To avoid confusion, the soffit is shown separately in Fig. f>, but as the lines would not be so close together when set out full size, this could be superposed on the same rod.
It is considered somewhat infra dig. by most joiners to have the various constructive joints shown on the rod, as they are presumed to know the rudiments of their trade, but as the correct size and disposition of tenons, etc., is of more importance in circular work than in square, it is very usual to set these out 011 the rod. The tenon on the left of Fig. 3 is the w"aynot to do it; that on the right the correct way.
i8f? SETTING-OUT FOR BRICKLAYERS
In the first ease, probably half the tenon would break off in the wedging up, through being cut across the grain. The joints in the door head would be grooved and cross-tongued and handrail-bolted ; those of the architrave, dovetail-keyed; the grounds, half-lapped and screwed ; and those between soffit and jambs, dowelled.
Bricklayers" Setting out.—Circle-on-eirc.le work, Figs. I and 2, page i8q, show the half elevation ami half plan of a semicircular arch in a circular wall, the jambs, reveals and soffits of the opening being perpendicular to the chord line of the arc, or, as it is more usually described in the trade, an opening with parallel jambs and soffit level at the crown.
These arches are invariably made, in gauged or cut work, ami the usual practice is for the carpenter to make a true " centre " to fit the required opening exactly in both plan and elevation, and the bricklayer, having first made an elevation on his bench board full size, applies the centre to the drawing and marks the intrados spacing of the arch on each face in turn and then joins up the points across the soffit with a straight edge, thus obtaining the shape of each brick on the soffit. This method has its drawbacks, as each brick must be scribed to the faces of the " centre," and it is necessary for the carpenter to make a. " centre " with compound curves, which is much more expensive than an ordinary barrel centre with which the job coidd be done equally well by the method of set ling out now to be described.
To set out the Elevation.—Draw the springing line, parallel to the edge of setting-out board, and far enough upwards to get the plan underneath as shown in the example. It is usual to strike the entire arch, but one half is really sufficient. Draw a centre line with the square, and at the intersection as centre and the " trammel rod " set to the required radius, strike the intrados and extrados of the arch, set out the springers and the key brick, the first on the springing line and the second equally on each side
oi centre line, then space out the extrados equally, with the compasses set to the thickness of a brick, ami, if the arc will not divide equally with this, reduce, the space until an equal division can be obtained, then draw the joints radiating from the centre to the division points. 1 his will give size of templet for the faces, to which the cutting box should be made.
Next, strike out the plan on the same centre line, and square the reveals and jambs from edge of board. 1 )raw in the plans of the bed joints by moving the square around the soffit successively, as shown by the numbers on Fig. i and indicated by dotted projector at joint No. 13. This gives the soffit joints or end shape of the bricks in plan oalyfl but not their real size; to obtain this a stretch-out of the soffit as shown in Fig. 3 is required. To obtain this, make the line a'-a equal in length to the curve line S-C, Fig. 1, and this can be done accurately enough by setting the compasses to the thickness of a brick on the soffit as seen in the elevation, and stepping it along the line the number of times there are bricks in the arch. (Only one-hall is shown, and this is usually sufficient.) Next draw perpendiculars from the division points of indefinite length, with the square. Then draw a line; tangent to the plan curve—-i.e. parallel with the springing line- -and carry the joints across to it, as shown by dotted projectors. Number each set as shown, then, measuring across each joint with the compasses 'from the tangent line, transfer the lengths to the stretch out line upon the corresponding number thereon, and so obtain a scries of points tlirough which the curves can be drawn, by bending a lath to lit them. Now we have the soffit as it would appear if stretched out flat, but as the arch is curved, this does not really give the accurate angles of each individual brick, and we must bend this stretch-out over the centre before we can get the true shapes. The best way to do this is to trace off the stretch-out on a strip of tracing linen, then to fasten this upon the " centre " with tacks keeping the crown at its proper projection beyond circle-on-circlk work
Was this article helpful?