Woodwork Joints Part 6

[Ill.u.s.tration: Fig. 133.--Occasional Stump Tenon.]

This type of joint is also used to connect the rail to the leg of an ordinary kitchen table (see Fig. 167).

Fig. 133 is a variation of the stump tenon, occasionally used where the work in hand demands a thin tenon and a stout stump to take heavy strains.

[Ill.u.s.tration: Fig. 134.--Joint for Inside Framing.]

[Ill.u.s.tration: Fig. 135.--Haunched Barefaced Tenon.]

A joint used for inside framing is seen at Fig. 134. The rails may be used as shown, but in the case of a door frame (as Fig. 132) they would have the inside edges grooved to receive the panels; the tenons would therefore be slightly narrower than shown, owing to the groove at each edge.

A HAUNCHED BAREFACED TENON, used in similar positions to Fig. 131, is shown at Fig. 135. The door or frame in this case would be made of matchboarding nailed on the back as shown in the plan at Fig. 127.

WEDGES.--Fig. 136 shows the method of cutting wedges which are to be used to wedge the tenons; this avoids waste of material. Some workers cut the wedges from the pieces left out of the haunching of the lock rail, or the bottom rail.

[Ill.u.s.tration: Fig. 136.--Cutting Wedges from Waste of Haunching.]

[Ill.u.s.tration: Fig. 137.--Stile and Cross Rail with Horn.]

A STILE AND CROSS RAIL, framed together, are shown at Fig. 137. The portion above the rail is called the horn, and it is usual to leave sufficient length of stile to project above and below the cross rails, so that there will be no tendency for the stile to burst out at the end whilst the cramping and wedging of the frame is in progress. On completing the framing the horn is cut away.

In Fig. 138 we have a type of joint frequently used for garden gates. The ill.u.s.tration shows the method of tenoning the three pieces to the top rail, barefaced tenons being employed.

[Ill.u.s.tration: Fig. 138.--Joint used for Garden Gates.]

[Ill.u.s.tration: Fig. 139.--Sprocket Wheel.]

[Ill.u.s.tration: Fig. 140.--Boring Tool.]

SPROCKET WHEEL.--At Fig. 139 are shown the guide bar and chain of a chain-mortising machine, two enlarged links of the chain being indicated at A. The chain is similar in construction to the driving chain of a bicycle, with the exception that it is provided with teeth which cut away the timber as the chain revolves. When using a chain mortiser the portion of the machine carrying the chain is fed downwards into the timber, thus cutting a clean and true mortise. If, however, a stump mortise is required it is necessary to pare away a certain amount of timber by hand, because the machine obviously leaves a semicircular bottom to the mortise. To overcome this difficulty the latest types of mortising machines have a square hole-boring attachment fixed alongside the chain. This tool, the working portion of which is ill.u.s.trated in Fig.

140, consists of a square hollow chisel (E), which is sharpened from the inside, and a revolving twist bit (D) fitted with spurs or nickers, but without a point (one spur can be seen at the bottom of the ill.u.s.tration).

This bit revolves inside the sh.e.l.l like a chisel, and bores away the superfluous timber, whilst the pressure exerted on the chisel causes the corners to be cut away dead square. A mortise 3/8 in. square by 6 ins. in depth may thus be cut. The portion marked A is the shank of the chisel (Fig. 140), where it is fixed into the body of the machine, and the hole at E allows the boring bit to free itself.

[Ill.u.s.tration: Fig. 141.--Method of Fitting an Interior Table Leg.]

[Ill.u.s.tration: Fig. 142.--Haunched Tenon for Skylight or Garden Frame.]

[Ill.u.s.tration: Fig 143.--Long and Short Shouldered Tenon.]

Fig. 141 indicates the method of fixing an interior leg to a table having a circular or straight top rail. The inlaid leg in this case is stump-tenoned into the top rail, and the inlaid portion of the leg is allowed to run through the rail, thus giving continuity of design.

Fig. 142 shows the application of the haunched tenon (Fig. 135) to the making of a skylight or garden frame. In this and similar cases the side rails are rebated as shown in the section, and the bottom rail is thinner than the side rails to allow the gla.s.s to finish level upon it.

LONG AND SHORT SHOULDERED JOINT.--Fig. 143 shows a haunched mortise and tenon joint having a long and short shoulder. This is a fairly common joint in framed part.i.tions for offices, framing for greenhouses, tool sheds, etc., and is a frequent source of annoyance to the amateur. It is necessary to use this joint when both the stiles and uprights are rebated, and it calls for accurate marking out and great care in the making.

[Ill.u.s.tration: Fig. 144.--Joint for Fencing.]

[Ill.u.s.tration: Fig. 145.--Example of Faulty Tenon.]

Fig. 144 shows the upright and rails of common garden or field fencing.

The tenons are bevelled to fit and wedge each other in the mortise. The ill.u.s.tration gives both cross rails as shouldered, but in many cases shoulders are omitted when the rails are not thick enough to carry them.

Fig. 145 indicates faulty methods of working a tenon. At A the saw has been allowed to run too far when cutting the shoulder, thus greatly weakening the tenon. At B faulty sawing has again occurred, and to remedy this defect the worker has resorted to paring the shoulder with a chisel.

Had the chisel been used vertically an undercut shoulder (as at B) would not have occurred. The trouble now is that the slightest amount of shrinkage in the width of the stile will show an open joint. The result will be the same if it is necessary to remove a shaving or two when planing or levelling up the face of the frame.

[Ill.u.s.tration: Fig. 146.--Self-wedging j.a.panese Tenon Joint.]

[Ill.u.s.tration: Fig. 147.--Tenoned and Scribed Joint.]

[Ill.u.s.tration: Fig. 148.--Mitred and Moulded Tenon Joint.]

[Ill.u.s.tration: Fig. 149.--Twin Tenons.]

A j.a.pANESE TENONED JOINT, little known and rarely used in this country, is shown at Fig. 146. For clearness the two parts are here shown separate. The joint is self-wedging and will be of interest to Handicraft Instructors.

A TENONED AND SCRIBED JOINT is seen at Fig. 147. The cross rail is cut at the shoulder, so as to fit the moulding which is worked on the stile.

This is a good joint in everyday use.

MITRED AND MOULDED JOINT.--Fig. 148 shows a type of joint largely used in light cabinet work. The method of mitreing the moulding and tenoning the stile to rail is indicated.

TWIN TENONS (Fig. 149).--The method of tenoning the bearers which carry the drawers, or the midfeather between two drawers, in a dressing table or similar carcase is here shown. On completion, the tenons on the midfeather are wedged diagonally.

[Ill.u.s.tration: Fig 150.--Method of Pinning.]

[Ill.u.s.tration: Fig. 151.--Joining Top Rails to Upright Post.]

PINNING.--Fig. 150 shows the tenoning of the inside end of a wardrobe to the top of the carcase. This is also called pinning. The tenons should be wedged diagonally. The tenons and the distance between the tenons are more satisfactory if made equidistant, because if slight shrinkage occurs this is partially equalised. The width between the tenons should in no case exceed 3 ins.

TOP RAILS.--At Fig. 151 is shown the method of joining the top rails to the post of a tool shed or similar outhouse. The two rails, which are at right angles to each other, are half-lapped and mortised; the tenon on the post runs entirely through them.

A TUSK TENON JOINT, with wedge, as used to secure the binder to the girder when making floors, is indicated at Fig. 153. The tenon here is narrow and engages the mortise, which is situated in the compressional fibres immediately adjoining the neutral layer. Fig. 152 shows a tusk tenon furnished with a drawbore pin.

[Ill.u.s.tration: Fig. 152.--Tusk Tenon.]

[Ill.u.s.tration: Fig. 153.--Wedged Tusk Tenon.]

Fig. 154 is a variation of Fig. 152.

Fig. 155 shows tusk and wedged tenons as used when making a portable book or medicine cabinet. The shelf is housed into the end, and the tenons run through the end and are secured by wedges. This allows the article to be quickly and easily taken to pieces for removal or re-polishing. The dotted line in Fig. 155 indicates that the shelf may be shaped if desired.

[Ill.u.s.tration: Fig. 154.--Another Type of Tusk Tenon.]

[Ill.u.s.tration: Fig. 155.--Tusk Tenon and Wedge.]

[Ill.u.s.tration: Fig. 156.--Wheelwright's Self-wedging Tenon Joint.]

In Fig. 156 a self-wedging mortise and tenon joint used by wheelwrights is shown. The dotted line (left-hand diagram) will indicate the amount of taper given to the mortise.