This section is from the book "A Practical Treatise On The Joints Made And Used By Builders", by Wyvill J. Christy. Also available from Amazon: Practical treatise on the joints made and used by builders.
Brace Joint is one connecting a brace to the timber or element it helps to confine. As a brace is either a strut or tie, the connection will accordingly be either in compression or tension, and both conditions are respectively noticed under Strut Joint and Tie Joint.
Bridle Joint, Sometimes Called Notch And Bridle
This is the name given in carpentry to a joint in which the mortise is supplanted by a tongued notch, and the tenon by a grooved abutment to correspond. The tongue which stands up across the middle of the breadth of the notch, as in Fig. 29, is called the bridle, and is about 1/5 the breadth in thickness. This joint has the advantage of being more easily got at and inspected throughout all its parts, and consequently of being more likely to be accurately fitted than a mortise and tenon, whose parts are concealed and not unfrequently suspected of being cut without the fulness and nicety essential to an exact fit. Fig. 29 represents a principal rafter about to be united to a tie-beam according to this plan, but a similar kind of joint can be equally well used between upright and horizontal timbers. Butt or Butting Joint. - This has been generally explained under Abutting Joint, and it remains only to add that butt refers usually to a square plain joint between two plain surfaces.
A facetious name given to a joint in carpentry worked from a centre, and somewhat of the nature of a rule joint as well as that of a dovetail, and useful so far as it accommodates itself in some situations to settlement. It is not considered effective, the reason for which is apparent from a glance at Fig. 30, which shows how prone the joint is to become loose through shrinkage.
There are four varieties of this joint which occur in carpenter's work, though perhaps the first is not actually made by this artificer. It is formed (1) when rendering timber work water-tight by driving tarred spun yarn or some similar stuffing into the joints or seams of planking, sheet piling, etc, and is executed by means of a hammer and caulking iron or chisel, the threads being driven in one after another into the seams, which are previously opened out or reamed with the chisel. After the yarn is well compressed and compacted into a dense watertight mass, it is payed over with a coating of hot pitch. Caissons, bridge timber-platforms, cofferdams, etc, are thus generally caulked. To this class may be added those instances in which pipe sockets are filled with wood wedges and the joints in cast iron tanks made sound with wood slips. (2.) When letting the corkings or caulkings of ironwork into timber, as, for example, when securing with coach screws or staples, the caulked ends of twisted dog irons to joists and wall-plates respectively. (3.) In connecting tie-beams with wall-plates, etc. This kind is made by cutting in the lower timber a notch with a cog left across it, as in Fig. 31, flush with the top surface, and in the under surface of the upper timber a notch to correspond with, and exactly fit, this cog, by which means the two are prevented from drawing away from each other. Odd as it may seem, this form of junction is called with apparent reason either a caulked, cauked, calked, cocked, cogged, or corked joint. (4.) This variety not only enjoys, according to association or taste, the whole string of aliases just enumerated, but in addition the term keyed. It occurs in built beams, and consists in cutting shallow transverse notches at regular intervals on the upper and lower edges respectively of the two timbers about to be uited, which are then bolted through or strapped together with the notches opposite, and when thus well secured they are kept from sliding by driving pairs of cogs or folding keys through, the holes so left between them.