Woodwork Joints Part 5

Fig. 111 is a "Combing or corner locking" joint, a method of making boxes by means of a continuous use of tongues and grooves instead of dovetails.

This type of joint is generally machine made. The amateur, however, who is not proficient to undertake a dovetailed box frequently uses this method.

[Ill.u.s.tration: Fig. 110.--Corner of Barred Door.]

[Ill.u.s.tration: Fig. 111.--Combing or Locking Joint.]

[Ill.u.s.tration: Fig. 112.--Single Loose Tongue and Double-tongue Joint.]

CORNER JOINTS.--Fig. 112 shows both a single loose tongue and a double solid tongue. Both are methods used to connect circular cornered work, such as a counter end, to the front framing.

Fig. 113 indicates a tongued and grooved joint suitable for edge or end jointing, such as fitting matchboarding round a chimney breast, making small jewel drawers, etc.

Fig. 114 is a tongued and grooved joint with a bead worked on same to hide the joint, sometimes called a staff-bead. It would be used in positions such as boarding around an upright iron pillar, etc., the bead giving a neat finish at each corner.

Fig. 115 is a similar joint, but at an obtuse angle. An example of its use is in fixing boarding around an octagonal column of brickwork.

[Ill.u.s.tration: Fig. 113., Fig. 114., Fig. 115. Examples of Tongued and Grooved Corner Joints.]

Fig. 116 shows a tongued and grooved mitre as used for strengthening the corners of cabinet work, such as tea caddies, small boxes, plinths, etc.

Two pieces of wood are glued in position and allowed to set prior to glueing and cramping the joint proper. These pieces are afterwards planed away, thus leaving a clear surface to the box sides.

Fig. 117 shows the method of working the groove in the above joints. The pieces are turned back to back, the mitres thus making a right angle. The guide on the grooving plane thus works against each face of the joint, and this ensures correct jointing.

Fig. 118 is somewhat similar to Fig. 113, but with a quarter circle mould to hide the joint.

Fig. 119 indicates the building up of a double skirting mould. C represents the brickwork, A the oak-framed panelling, and B the packing and fixing block. A wide skirting of this type is made in two portions for convenience in working the moulding and to prevent undue shrinkage.

[Ill.u.s.tration: Fig. 116.--Cramping a Tongued and Grooved Mitre.]

[Ill.u.s.tration: Fig. 117.--Working a Groove.]

[Ill.u.s.tration: Fig. 118.--Corner Joint with Corner Mould.]

Fig. 120 ill.u.s.trates the use of a tongued and grooved joint for fixing together the sides of a corner bracket, and the same method holds good when jointing a corner cupboard. A capping mould or top shelf will conceal the joint; it then has the appearance of a glued b.u.t.t joint, but is of course considerably stronger. No screws or nails are required if this joint be used.

PLOUGHING.--When grooves have to be worked in the edge or face of a board to receive tongues, the process is generally called ploughing, and it is usually accomplished by a special tool called a plough (or, as it is occasionally spelt, "plow"). When a plough plane is bought it is usual to procure eight plough bits or blades of various sizes to fit the plane. In Fig. 121 is given the sketch of a plough plane with the names of the various parts lettered thereon.

[Ill.u.s.tration: Fig. 119.--Double Skirting Mould.]

[Ill.u.s.tration: Fig. 120.--Joint for Corner Bracket or Cupboard.]

The board or boards which it is desired to groove are first planed straight and true, exactly as though it were desired to make a glued or b.u.t.t joint. One of the boards is now placed edge way up in the vice and with the face side to the worker.

Take the plough plane and select a suitably-sized blade; fix it in the plane in the usual way, allowing the cutting edge to project beyond the steel skate about 1/32 in., and securely drive up the wedge. Next loosen the small boxwood wedges at the side of each stem, and adjust the plane by tapping the stems with a hammer until the cutting iron is in the desired position; then knock up the small wedges nice and tight. When setting the fence to or from the blade it is a wise precaution to measure the distance from the fence to the skate at each end of the plane; this will ensure the skate being parallel to the fence. The neglect of this is a source of annoyance to many amateurs. Now adjust the depth stop by turning the screw at the top of the plane, measuring the depth of the required groove from the edge of the blade to the stop, and carefully lock the screw which adjusts this stop.

[Ill.u.s.tration: Fig. 121.--The Plough Plane and its Parts.]

The plane is now ready for use. Hold the fence close up to the side of the timber, the hands in position as shown at Fig. 122, the position of the body being that generally a.s.sumed in planing. Move the plane backwards and forwards in the usual manner, beginning the cut at the end of the board nearest to the vice jaws (the front), and proceed with the planing until the depth stop is in contact with the wood. Then take a step backwards and repeat the process until the whole length of the groove is ploughed. Care must be taken to force the fence up to the board with the left hand, whilst the right hand thrusts the plane backwards and forwards, and the plane must be kept vertical.

[Ill.u.s.tration: Fig. 122.--Method of using the Plough Plane.]

TONGUEING.--The grooves having been completed, the tongues have to be made. Fig. 123 shows a sketch of a board and the method of marking out cross tongues (A) and feather tongues (B). The usual procedure for making cross tongues is to plane the end of the board and use a cutting gauge to give a line the required distance from the end (see sketch). The board is sawn with a tenon or panel saw, and the piece of timber for the tongue is thus procured. If a feather tongue is to be used it is cut diagonally from the board (B) and the ends cut square as shown by the dotted line.

[Ill.u.s.tration: Fig. 123.--Method of Marking Out for Cross Tongues and Feather Tongues.]

Feather tongues can be obtained in fairly long lengths out of narrow boards, whilst on the other hand cross tongues are limited by the width of the board. After cutting off the tongues, they require planing with nicety to fit the grooves, and the advantage of a grooved board (Fig.

105) will be appreciated. A glue spoon similar to a plumber's ladle is generally used to pour the glue into the grooves, and it is customary to glue the tongue into one board first; after allowing this to set, the joint is completed in the usual manner.

TONGUEING PLANES.--Fig. 124 shows the end view of a tongueing plane for working matched joints out of the solid. The method of holding and using the plane is similar to the directions given for using the plough. The part lettered F (in front) represents the fence, which in this case is not adjustable.

[Ill.u.s.tration: Fig. 124., Fig. 125. End Views of Tongueing and Grooving Planes.]

In description Fig. 125 is similar to Fig. 124. The steel skate runs in the groove and supports the cutting blade similar to that in the plough plane, and provided a grooving plane of this type is of suitable width it may be used for making grooves for loose tongues. There is on the market a metal plane which is specially designed with handles at both ends.

This plane carries a grooving iron on one side and a tongueing iron on the other side; thus with one plane both the tongue and the groove can be worked.

[Ill.u.s.tration: Fig. 126.--Tongueing Shoulders of Tenons.]

Fig. 126 shows the method of tongueing the shoulders of tenons as used in thick timber which is to be veneered on the face. A temporary piece of wood (A) is put between the tenon cheek and the saw, thus forming a guide for the latter. After cutting one saw kerf a thicker piece is made and a second saw kerf cut; the waste between the saw kerfs is now removed with an 1/8 in. chisel and this completes the groove. A tongue of this type acts as an extra tenon and prevents the joint from "lipping" (becoming uneven) on the face side.

THE MORTISE AND TENON JOINT

A mortise and tenon joint is the method of joining timber by working a solid rectangular projection in the one piece and cutting a corresponding cavity to receive it in the adjoining piece. The projection is called the tenon, and the cavity the mortise. Joints of this type are secured in various ways. Small wedges, wooden dowels, metal dowel pins, glue and paint are frequently used, and prior to the introduction of glue we have examples of Egyptian furniture in which the mortise and tenon joints were united by a composition of cheese.

[Ill.u.s.tration: Fig. 127.--Barefaced Tenon Joint.]

[Ill.u.s.tration: Fig. 128.--Stub Tenon.]

BAREFACED TENONS.--Fig. 127 ill.u.s.trates the joint in its simplest form and shows a tenon having only one shoulder. This is called a barefaced tenon, and it will be noticed that the portion which carries the mortise is thicker than the rail on which the tenon is cut. The joint is therefore level (or flush as it is called) on one side only, and it should never be used at the corner of a frame. It is a useful interior joint for framing that has to be covered on the back side with matchboarding, and allows the work to finish level at the back when the boarding has been applied (see plan, Fig. 127).

STUB OR STUMP TENON (Fig. 128; also occasionally called a joggle tenon).--The ill.u.s.tration shows a tenon as used in the interior of a frame. The tenon is not allowed to run through the stile, and unsightliness on the edge is thus avoided. This type of tenon is often used at the corner of a frame, and it then requires to be haunched. A good workshop method of gauging the depth of the mortise for a stub tenon is shown in Fig. 129; a piece of gummed stamp paper is stuck on the side of the mortise chisel, indicating the desired depth of the mortise. This greatly facilitates the work, as it is not necessary to be constantly measuring.

A HAUNCHED TENON as used at the end of a door frame is shown at Fig.

130.--In this case it will be seen that the width of the tenon is reduced, so that sufficient timber will be left at the end of the stile to resist the pressure of the tenon when the joint is driven together.

The short portion (A) which is left on the tenon is called the haunch, and the cavity it engages is termed the haunching. The haunch and haunching prevent the two pieces of timber lipping, or becoming uneven on the face side, as would be the result if it were cut away entirely up to the shoulder.

Fig. 131 shows the type of tenon and haunch used when the stile or upright rail is grooved to receive a panel. In this and similar cases the haunch is made the same width and the same depth as the groove; the groove therefore acts as the haunching. An application of this joint is shown in the top rail of the door frame, Fig. 132.

[Ill.u.s.tration: Fig. 129.--Method of Gauging for depth of Tenon.]

[Ill.u.s.tration: Fig. 130.--Haunched Tenon used at end of Door Frame.]

[Ill.u.s.tration: Fig. 131.--Haunched Tenon used when Stile is Grooved for Panel.]

[Ill.u.s.tration: Fig. 132.--Application of Haunched Tenon Joint to Door Frame.]