Part 17 (1/2)

Puzzle Joints are not only interesting in themselves, but are often excellent studies in craftsmans.h.i.+p. The majority of them, if to be satisfactory as puzzles, call for very careful setting out and cutting, entailing the same degree of skill that is demanded for high-cla.s.s cabinet work. For this reason several examples may well find a place in a volume dealing with woodwork joints. As a rule, these puzzles should be made in hardwood, such as dark walnut or beech, as in whitewood the joints are soon liable to wear.

[Ill.u.s.tration: Fig. 369.--Sketch of the Completed Chinese Puzzle.]

CHINESE PUZZLE.--The ingenious puzzle of the Chinese type shown in Fig.

369 is probably older than many of us could guess, but as it is one that can be made by any woodworker we give full directions as to how it may be constructed. The complete article may be called, in form, a six-pointed pyramid. It is made up of twenty-one different pieces, each cut from wood 1/2 in. wide and 1/2 in. thick; 3/8 in. wood may be used if preferred.

For the purpose either sycamore or white maple is the most useful.

[Ill.u.s.tration: Fig. 370., Fig. 371., Fig. 372. The Three Cross Pieces.]

[Ill.u.s.tration: Fig. 373.--Key Piece.]

The pieces required are as follows:--

Fig. 370.--Six pieces, 3-1/2 ins. long, with a half slot cut in the centre as shown. This slot must be exactly the width of the wood's thickness, and cut exactly half way through, so that, if two pieces are placed across by means of the halved joint, their surfaces will be flush.

The slot must also be exactly in the centre.

Fig. 371.--Six pieces, size 2-1/2 ins. long, with a half-cut centre slot similar to that of Fig. 370.

Fig. 372.--Six required, these being 1-1/2 ins. in length, and with slots in the middle as before.

Fig. 373.--One of these last six requires special treatment, as it forms the key block of the puzzle. After its slot has been cut, one half of the narrow part must be sawn away, as shown in Fig. 373. The inner edge must also be gently rounded. The special use of this vital piece, which we will call the ”key,” will be fully explained presently.

Fig. 374.--Then, in addition to these, there are three central bars to make. Like the other parts they are 1/2 in. by 1/2 in., but are each 4-1/2 ins. long, and are cut as shown in Fig. 374. The end projections _a_ are 1/2 in. long, and the cut-away part is exactly half the depth of the wood. Two of the three pieces (X and Y in Fig. 374) are similar, but the slot _b_ of the third one (Z) is only 1/4 in. wide instead of 1/2 in.

As will be noticed, this 1/4-in. slot is _not_ in the centre, but corresponds with the right-hand half of the larger slots of X and Y.

[Ill.u.s.tration: Fig. 374.--The Central Bars.]

In making these twenty-one pieces, what should be borne in mind is that the different parts fit closely into each other. Consequently the slots, in width, must be cut so as to grip the thickness of the wood; in depth they must be exactly half this thickness.

FITTING THE PUZZLE.--The three central bars must first be joined, as those form the skeleton framework of the structure. Fig. 375 shows them in position, but as it is a puzzle in itself as to how they can be got thus some explanation is necessary.

[Ill.u.s.tration: Fig. 375.--The Three Central Bars in Position.]

[Ill.u.s.tration: Fig. 376.--How to Adjust the Bars. (Note position of projecting ends, _a_.)]

FIRST STAGE.--First take the bars X and Y (see Fig. 374) and arrange them as shown in Fig. 376. It is most important that the projections _a_ of X face upwards, and that the projections _a_ of Y face towards the centre.

Then take the bar Z and bring it flat into the slot of X. The little slot of Z, however, must remain _above_ the slot of X. Then slide the bar Y along to the centre, so that the part lettered _c_ slips into the little slot of bar Z.

This may seem confusing to read, but it is easy to follow when the pieces are in one's hand. The result of this rather clever arrangement is that the six arms of Fig. 375 are all exactly the same length, width, and thickness. They are also arranged so that in each arm may be clasped one piece each of Figs. 370, 371, and 372. The three central arms may, of course, be set up in a different order, and here we have merely chosen the way that is the most simple to describe and ill.u.s.trate.

[Ill.u.s.tration: Fig. 377.--Beginning to place on the Cross Pieces.]

[Ill.u.s.tration: Fig. 378.--Placing the Key Piece to overlap end projection of Central Bar.]

SECOND STAGE.--In the remaining part of the work the chief difficulty is to keep the puzzle from falling to pieces before the key finally locks it. Take the longer cross parts, Fig. 370, and clasp one to each arm. The six need not all be put on meanwhile, but only those which are most easily handled. The next size (Fig. 371) may then be put on.

In the ordinary course each arm could be completed with its three cross pieces till the sixth was attempted, and here the reader would find that, at the last moment, his attempt was frustrated. He could not get the last small piece in, as other bars lock the puzzle. Here it is that the ”key” comes in.