Part 1 (1/2)
Woodwork Joints.
by William Fairham.
EDITORIAL FOREWORD
To be successful in woodwork construction the possession of two secrets is essential--to know the right joint to use, and to know how to make that joint in the right way. The woodwork structure or the piece of cabinet-work that endures is the one on which skilful hands have combined to carry out what the constructive mind planned. And it is just here that the present Volume will help, not alone the beginner who wishes preliminary instruction, but also the expert who desires guidance over ground hitherto unexplored by him.
In the preparation of this new edition the Publishers have secured the services of Mr. William Fairham, by whom the chapters have been carefully revised and re-ill.u.s.trated. Although intended for the practical man, and not professing to be a graded course of ”educational woodwork,” the Volume is one which Handicraft Instructors will find of the greatest value in conducting woodwork cla.s.ses. No book hitherto published contains such a variety of ill.u.s.trations of joints, almost all of which will form suitable exercises of practical educational importance in a woodworking course.
J. C. S. B.
THE GLUED JOINT
The glued joint in its various forms is in use in every country in the world, and is frequently met with in mummy cases and other examples of ancient woodwork. Alternative names under which it is known are the b.u.t.t joint, the rubbed joint, the slipped joint, whilst in certain localities it is known as the slaped (p.r.o.nounced _slayped_) joint.
[Ill.u.s.tration: Fig. 1.--Simplest Form of Glued or Rubbed Joint.]
The glued joint is made by planing two pieces of timber so that when placed together they are in contact with each other at every point; they are then usually united with glue. Fig. 1 shows a sketch of a b.u.t.t joint in its simplest form. In Fig. 2 is indicated the method of holding the joint whilst being glued; the upright portion is held rigid in the bench vice, thus leaving the left hand to hold the piece which is to be jointed, whilst the right hand operates the glue brush. The pieces of wood which form a b.u.t.t joint may be glued together with or without the aid of cramps or artificial pressure. If the joint is to be made without cramping, the two surfaces of the timber are warmed so as not to chill the glue. The surfaces are then glued and put together and rubbed backwards and forwards so as to get rid of the superfluous glue. They are then put aside to dry.
GLUEING.--The better the glue penetrates into the pores of the wood, the stronger the joint will be; for this reason timber of the loose-fibred variety, such as pine, etc., will hold up at the joint better than hardwoods like teak and rosewood. The glue used for jointing should be neither too thick nor too thin; the consistency of cream will be found suitable for most purposes. It should be nice and hot, and be rapidly spread over the surface of the wood.
[Ill.u.s.tration: Fig. 2.--How the Wood is held whilst Glueing.]
If light-coloured woods, such as pine, satinwood, sycamore, etc., have to be jointed, a little flake white should be procured and mixed into the liquid glue. This will prevent the glue showing a thin black line on the joint.
Broad surfaces of close-grained hardwood having a s.h.i.+ny surface are usually carefully roughened with a fine toothing plane blade previous to glueing.
SUPPORTING THE JOINT.--The jointed boards should not be reared up against a ”bench leg” or wall without having any support in the centre, as dotted line at Fig. 5, because in all probability they will fracture before the glue has time to set; and, when we go to take them up to renew working operations, we shall be annoyed to find that they have a.s.sumed a position similar to that at Fig. 5 (shown exaggerated), and this will, of course, necessitate re-jointing.
[Ill.u.s.tration: Fig. 3.--Correct Jointing.]
[Ill.u.s.tration: Fig. 4.--Faulty Jointing.]
[Ill.u.s.tration: Fig. 5.--Boards unsupported.]
[Ill.u.s.tration: Fig. 6.--Boards supported.]
[Ill.u.s.tration: Fig. 7.--(A) Glued Slip, (B) Glued Moulding.]
[Ill.u.s.tration: Fig. 8.--Grain alternating.]
A correct method to adopt is seen at Fig. 6. Here we have supported the joint by rearing up against the wall a couple of pieces of batten, one at each end of the board, thus supporting it throughout its entire width until the glue is thoroughly set. The two or more pieces of timber in a b.u.t.t joint adhere by crystallisation of the glue and atmospheric pressure. A well-fitted joint made with good quality glue is so strong that, when boards of 3 feet and upwards are jointed together by this method, the timber in most cases will break with the grain sooner than part at the joint.
b.u.t.t joints may be cramped up, if desired, and it is customary to warm them as previously stated. In the absence of the usual iron cramp, the amateur may make an excellent wooden arrangement out of any odd pieces of timber that happen to be handy. Two blocks of hardwood are screwed on the base board at a suitable distance for the work in hand; the boards to be jointed are glued and placed in position between the blocks; and the two hardwood wedges are inserted and hammered in opposite directions to each other, thus exerting the desired pressure. An example of this method of cramping is shown in Fig. 25, which also indicates the use of iron ”dogs.”
When jointing, care should be taken to first plane up the boards true on one side--_i.e._, take them out of winding. The method of testing for this is shown at Fig. 9, and it may with advantage be used when jointing the edges of the boards. Two laths or strips of wood are planed up to exactly the same width, having their edges straight and parallel. One edge of each lath may, if desired, be bevelled a little. The method of using these ”twist sticks” or ”winding laths” is to put them on the board as indicated, and sight along their top edges. The winding laths, being much longer than the width of the board, show up the irregularity greatly p.r.o.nounced.
THE TOOLS generally used for making the b.u.t.t joints are:--