Bookshelf design: Because I am not a professional craftsman, there are many restrictions on materials and processing methods. At the same time, the cost should not be too high, otherwise it is better to buy ready-made ones directly. These limitations make the conceptual design process more complicated. 1, plate selection. If the bookcase is full of books, the bottom plate will bear great pressure, even if it can bear it temporarily, but if the plate is not good, it may creep. In addition, my bookcase is not a ready-made plate, so try to be consistent in length and width, which is convenient for cutting. First go to the building materials city. The boards are all 4 square meters, not for retail. One piece is nearly 100, and I only want three pieces of 80cm X 25cm. Occasionally, scraps will be left, but they are all made of sawdust and glue, and the bearing capacity cannot be guaranteed. So I went to the home supermarket, and there were ready-made wooden floors with suitable length and width. Just some of them could be sold one by one, but the cheapest one, 19 yuan, was too expensive ... Finally I went to Yishan Road and found a shop selling wooden boards. There happened to be a 25cm X 242cm wooden board together, and he had a chainsaw there. It was successfully sawed into three pieces and cost 28 yuan (. 2. Suspension mode. There are several schemes: 1, drilling holes in the corner of the board, wearing a rope, tying a knot on the rope to block the board; 2. Use two parallel ropes, fix a stick perpendicular to the rope between the two ropes, make a ladder sample, and use two ladders to hang the board; 3. Replace the rope in Scheme [2] with an iron chain. Scheme 1 has simple structure and convenient installation. However, when drilling holes at the edge of the plate, there will be great stress concentration at the edge of the hole, and the hole is close to the edge of the plate and easy to break. In addition, without drilling tools, it is impossible to accurately ensure the position of the knot. The advantage of the second scheme is that the board is simple to place, but it can move left and right and needs to be fixed separately. In addition, the accuracy of knot fixing is not high, and whether it slides under great pressure cannot be guaranteed. The advantage of the third scheme is that the chain has high bearing capacity, the vertical bar is easy to fix, and there is no problem of loose knot and slip knot. However, there is no place to sell foreign chains. Finally, I rode to a section selling hardware equipment near Zhongjiang Road, and found that there was wire for sale, which was the kind in the brake line of bicycles, only thicker than that on bicycles, and there was also this wire fastening device for sale. I took a look and came out to think for half an hour on the nearby bridge. I thought it was very operable, so I bought15m wire and 16 fastener. I bargained with my boss, wire 1 yuan/meter, fastener 60 points/piece. I gave him a total of 22 yuan, plus the board, a total of 50 yuan. It was already five o'clock in the afternoon when I came back after I installed and bought the wire. After eating in a hurry, I borrowed a hammer and pliers from the mechanic and began to install my bookshelf. I can't understand the specific process without video recording, but I always feel it. "Learning from practice" is not only a horse's indoctrination, but also a viewpoint in western management theory, which I deeply realized in the process of installing bookshelves. Although the university has studied mechanical drawing and has certain three-dimensional thinking ability, it still cannot fully consider possible problems. The original scheme exposed huge problems in the specific operation process, so that a completely different suspension scheme was adopted. Solving practical problems does not need to be too precise in mathematics. "Practicality" and "ability to solve problems" are the highest standards. Because the bookshelf needs to lean against the wall (the back and forth shaking is limited, and the friction generated after the wall is pressed by the bookshelf can limit the bookshelf from shaking left and right), the iron wire is not perpendicular to the horizontal plane, and there is no tool to accurately measure the specific angle, which makes me think completely from the perspective of statics and fall into a dead end, and I can't find a horizontal plane to put the board. Finally, it was solved in this way. Brother Duoguang pressed the board with his hand, visually reached the level and fixed it, which was the datum plane. Finally, it took one night to install two boards at 1 1: 30. The next morning, it took an hour to install the last board, and my bookshelf was completed:)