Fig. 264-2 Fished
No 3. In a fished joint keys are often inserted between the fish-plate and beam at right angles to the bolts in order to lessen the strain that comes upon the bolts when the joint is subjected to tension. In wide pieces and for extra strength, as in bridge work, the bolts may be staggered.
Fig. 264-3 Fished and keyed
Nos. 4, 5, 6 and 7. A scarf or spliced joint is made by joining together with flush surfaces the ends of two timbers in such a way as to enable them to resist compression, as in No. 4; tension, as in No. 5; both, as in No. 6, where the scarf is tabled; or cross strain as in No. 7. No. 4 is used in house sills and in splicing out short posts, Nos. 5 and 6 in open frame work. No. 7 with or without the fish-plate, is used in boats and canoes, and is sometimes called a boat-builder's joint, to distinguish it from No. 4, a carpenter's joint. A joint to resist cross strain is stronger when scarfed in the direction of the strain than across it. No. 7 is the plan, not elevation, of a joint to receive vertical cross strain.
Fig. 264-4 Spliced for compression