JOINERY. 



of wood upon the back of it, clofely fitted to its furface, and 

 the other joints to each ocher, the fibres of the blocks cor- 

 rcfponding with thofe of the veneer. 



A tliird method is to make a cradle and place the 

 veneers upon it, confining one end of them i'pread in the glue 

 between the veneers with a brudi, and fix a bridle acrofs, con- 

 fining the ends of this bridle either by nsils or by fcrews ; 

 open the veeners again, and put in glue a fecond time be- 

 tween eacli two, and fix another bridle acrofs them : pro- 

 ceed in this manner to the other extremity. 



A fourth method is to run a number of equi-diftant 

 grooves acrofs the back of the board at right angles to its 

 edges, leaving only a fmall thicknefs towards the face, let 

 this be bent round a craddle or templet made oh purpofe ; 

 and let the grooves be filled with flips of wood, which, 

 after the glue is quite dry, are to be planed down to the 

 furface of the cylindric board, which may be lliffened with 

 canvas glued acrofs the back. 



Inilead of ufing a grooving plane, workmen frequently 

 make kerfs with the faw ; but this is not fo ftrong when 

 finifhed, as it is very difficult to infert the flips, and very 

 uncertain as to the depth of each of the kerfs, which will 

 occafion a very unequal bending of the board, if not to a 

 regular depth. 



To knd a board, fo as to form the fruftum of a (one, or 

 ant fgmental portion of the frujlum of a cone, fuch as the fofjit 

 of the head of an aperture. — Find the form of the covering 

 according to the geometrical principles of carpentry ; 

 cut out a board to this form, and run a number of equi- 

 dillant grooves acrofs it tending to the centre : this being 

 fixed to a templet made to the furface of a cone, proceed 

 and fini(h it in the fame manner as in the lad method fliewn 

 fcr a cylinder. 



To lend hoards fo as to form a fpheric furface.'—yid.'ke a 

 mould to the covering of a given portion of the fphere 

 in piano, according to the geometrical principles of car- 

 pentry ; complete the number of ftaves by this mould ; 

 make a templet or mould to a great circle of the fpher; j 

 groove each of the ftaves acrofs at right__ angles to a 

 line paffing through the middle, a^^l tend it round the 

 templet ; put flips in the groir.cj; kftly, ihoot the edges of 

 the ftaves, fo as to be in ^(affes tending to the centre of the 

 fphere : thefe ftavc; being glued together will form a fpheric 

 furface. 



To glue vp the fiaft of a column. — Defcribe two circles of 

 diameters, equal to tlioie of the fuperior and inferior ends of 

 the fliaft. 



Circumfcribe thefe by polygons, confifting of the fame 

 number of regular fides as the column is to confift of ftaves. 

 From the angles draw lines to the centre, which will give 

 the bevels for working the edges of the ftaves. In this pro- 

 cefs, after two pieces are glued together, and dried, pro- 

 ceed to glue a third piece in the fame manner and fo on to 

 the laft but one. The laft, previous to being glued, the 

 blocks fliould be fixed upon it, and then the whole may be 

 clofed in. N. B. The number of ftaves fliould be eight or 

 twelve, otherwife the joint will fall in the middle of the 

 ilutes, which fliould not be in the cafe. It is a very good 

 method to diminilh the ftaves, previous to their being glued 

 together, as otherwife the wafte of ftiiff^ v.ould be very 

 great. 



To glue up the bafe of a column in f-oeral horizontal courfes, 

 or rings, in order to be turned in a lathe. — Confider the num- 

 ber of horizontal or bevel joints, which are belt made at the 

 internal angles of mouldings ; prepare a board, fo as to have 

 a plain furiace ; let a circle be dcfcribed on the plane of a 



diameter, equal to the diameter of the greateft circle in the 

 heiglit of the courfc, and circumfcribe an equilateral poly- 

 gon about the circle, with as many fides as there are to be 

 pieces in a courfe, and from the angles draw lines towards 

 the centre: then any radial line, and one of the adjoining 

 fides of the polygon, will form the angle by which the ends 

 of every two pieces that are to form the courfe will meet, fo 

 as to make their planes coincide. The geometrical part 

 being thus finiflied, prepare the pieces each in length equal 

 to the fide of the polygon, with an acute angle at each end 

 from the outer fide, equal to the aforefaid angle on the 

 board, fo that each piece will thus have a longer and a 

 fliortcr fide : apply the longer fide of each piece to the poly- 

 gon, the fliorter lide being next ts the centre, fo that one 

 of the ends may coincide with a radial ; then the other end 

 «ill alfo coincide, and thus the whole will meet together, if 

 the work be true. But as this is difScult, it is common to 

 allow the pieces to be a fmall matter longer, in order ti> 

 plane them, fo as to make clofe work : for thou^ih the 

 methods be true, the workman, though ever fo careful, can- 

 not work to geometrical exactnefs ; even the thicknefs of 

 fliaving, or the fmallell degree of twift in the board, will 

 fpoil the work. Suppofe the courfe completely jointed, 

 take the wliole to pieces, and glue the furfaces which are to 

 meet each other, and rub each two adjacent pieces to 

 a-joint, until the whole ring or courfe is firmly clofed. 

 When the glue is dry, plane the upper fide truly ; take the 

 radius of the greateft projeding member in the next courfe, 

 and defcribe a circle upon the top of the courfe, on the fame 

 axis with the centre of the lower circle ; and with the centre 

 of this circle, in the plane of the top of the courfe, bifeft 

 any one of the arcs comprehended between two adjacent 

 joints ; and from the point of bifedtion, divide the circum- 

 ference into as many equal parts as there arc pieces in the 

 under rourle, and draw radiating lines towards the centre : 

 join every two neareft points in the circumference, and thus 

 an infcribed polygon will be formed: draw Ji;;^:' io.Uui-U 

 the circurrf::^-,,^^ pnr-irel to the fides of the infcribed poly- 

 gon, and thus a polygon will be made to circumfcribe the 

 circle : produce the radiating lines, until they meet the 

 angles of the circumfcribing polygon ; then the fides of the 

 circumlcribing polygon will be the fituations of the bottom 

 edge of the vertical outer fides of the fecond courfe, and the 

 radiations the fituations of the joints. Proceed, as in the 

 firft courfe, to adapt the pieces to their refpeitive fituations, 

 making clofe work : glue each piece to its place on the 

 lower courfe, and likewife the joints ; and when the glue of 

 this courfe is dry, its upper fide may be planed true. Pro- 

 ceed with the uppermoft courfe in the like manner, making 

 the joints fall in the middle of the lengths of the pieces of 

 the lower courfc ; and when finiftied, the work may be fent 

 to the turner. 



To glut up the Ionic and Corinthian capitals for carving — 

 The abacus muft be glued in parts, fuch that their joints 

 may be in vertical planes. The leaves and caulicoles of the 

 Corinthian capital may be firft made of rettangular blocks, 

 and fixed to the vans. 



To make a cornice round a cylindric body out of the leaji 

 quantity of wood, wlicn the body is greater than a half cylinder, 

 and concave, and -when the members -will nearly touch a right 

 line applied tranfverfiy. — Draw a fcftion of the cylinder 

 through its axis, and let the fedlion of the cornice be reprc- 

 fented upon the cylindric leflion. Draw a tranfverle line 

 touching the two extreme members of the cornice : parallel 

 to this line draw another hue within, at fuch a diftance from 

 the former as may be found necefTary for lliicknefs of ftufi"; 

 produce this laft line, until it meet the line reprcfeiiting the 

 Y y 2 axis 



