The King Post Bridge.
The other bridge on the Schreiner property was built in the following summer, just before we started on our second expedition to Willow Clump Island. It spanned the brook at the gorge, and was therefore a more difficult engineering feat. Mr. Schreiner himself asked us to build it, and we felt greatly honored by the request. A search was made in the Van Syckel library for a suitable type. At last we found one that seemed properly suited to the requirements. It was called a “king post truss,” and was very similar to the king rod bridge. While the design of the bridge was simple, yet it required some ingenuity to put it together. In setting up the other bridge the scow had been anchored in the center of the stream and used as a working platform, from which it had been an easy matter to put the various parts together. In this case our scow was obviously of no use, so we laid a couple of long logs across the chasm, and a few slats were nailed across them to provide a temporary bridge or working platform. The platform sagged considerably at the center, because the span was fully eighteen feet; but the logs were large, and we knew they were strong enough to support our weight. However, as an extra precaution, we tied the ends to stakes driven in the ground, so that they could not possibly slip off the banks.
First we set about constructing the king posts, which were made as shown in Fig. 101. Two stout posts 7 feet long were connected at the top by a tie stick, which spaced them 4 feet apart. To make a secure fastening they were notched
Fig. 101. The King Post Frame. together and strengthened with diagonal braces. Each king post was notched on opposite sides, at about thirty inches from the top. A temporary tie piece was also nailed across the lower ends of the king posts. The frame thus formed was set up at the center of the span and temporarily held by nailing the lower tie piece to the working platform. Four stout spars were now cut, each about fifteen feet long. Taking a pair at a time, we planted their lower ends firmly in the opposite banks and sawed off their upper
Fig. 102. The King Posts Set in Position. ends until they could just be hammered into the notches in the king post. This required careful fitting, but by making the spars a little too long to start with, and then shaving them down with a draw-knife, we managed to make fairly good joints. A couple of long wire nails in each spar made the structure perfectly secure. The king posts were now sawed off just above the temporary tie piece, and the permanent cross beam was fastened to these ends with straps of heavy wire wound tightly about them. The working platform sagged so much that we were able to lay this cross beam above it. From the ends of the cross beam diagonal braces extended to the king posts (Fig. 103). Our working
Fig. 103. The Permanent Cross Beam Made Fast. platform was now removed and replaced with the permanent floor beams, which were firmly nailed to the center cross beam and to the inclined spars at the shore ends. The floor beams were quite heavy and needed no support between the king posts and shore. A rustic floor was made of small logs sawed in two at Mr. Schreiner’s sawmill. Light poles were nailed to the flooring along each edge, giving a finish to the bridge. We also provided a rustic railing for the bridge of light poles nailed to the king posts and the diagonal spars.